INTRODUCTION
Malformations or defects resulting from disturbance of growth and development are known as developmental anomalies. A large number of such developmental anomalies, which involve the body in general and oral structures in particular can occur during the embryonic life. Manifestations of these defects are evident either at birth or sometimes after birth. These anomalies often have some serious implications on the further growth process of the involved organ in the later phases of life.
Moreover, developmental anomalies affecting the teeth are seen more often then any other defects in the oral cavity.
These disorders of development of teeth may be due to abnormalities in the differentiation of the dental lamina and the tooth germs (abnormal morphodifferentiation) resulting in defects in the number, size and form of teeth.
Besides this, abnormalities in histodifferentiation may cause defective formation of dental hard tissues, resulting in the disturbance of tooth structure. Abnormalities of his to differentiation occur at a later stage during development than abnormalities of morphodifferentiation.
Types of Developmental Anomalies
- Congenital anomalies The defects, which are present at birth or before birth during the intra-uterine life, are known as congenital anomalies.
- Hereditary developmental anomalies When certain defects are inherited by the offspring from either of his parents, it is called hereditary anomaly. Such types of anomalies are always transmitted through genes.
- Acquired anomalies Acquired anomalies develop during intra-uterine life due to some pathological environmental conditions. They are not transmitted through genes.
- Hamartomatous anomalies A hamartoma can be defined as an excessive, focal over growth of mature, normal calls and tissues, which are native to that particular location.Developmental abnormalities occurring due to such hamartomatous change in the tissue are known as hamartomatous developmental anomalies.
- Idiopathic anomalies Developmental abnormalities of unknown cause are called idiopathic anomalies.
DEVELOPMENTAL ANOMALIES OF ORAL SOFT TISSUES
ANOMALIES OF LIPS AND PALATE
LIP PITS AND FISTULAS
Definition
Lip pits are congenital invaginations which can either involve the paramedial portion of the vermilion border of lower and upper lips or the labial commissural area.2
Origin
Both the lip pits and the commissural pits are developmental malformations, which appear to be inherited as autosomal dominant traits.
Clinical Features
- The lip pits can be either unilateral or bilateral and are more commonly seen on the lower lip.
- These pits can be up to 3–4 mm in diameter and may have a depth of up to 2 cm. Often they communicate with an underlying minor salivary gland.
- Lip pits often show a female predilection and their frequency ranges from 1: 75000 to 1: 100000 among Caucasians.
- Congenital lip pits may occur either as an isolated finding or they may be associated with cleft lip or cleft palate (van der Woude's syndrome).
- Mucous secretion is visible at the opening of those pits, which communicate with underlying salivary gland.
- The commissural pits measure from 1 to 4 mm in diameter, are found either bilaterally or unilaterally and often they have a familial tendency.
- Commissural pits can occur in association with multiple preauricular pits.
- Unlike lip pits, the commissural pits are more frequent among males and black people are affected more often than whites.
- In both the cases of lip pits and commissural pits, there is no sign of inflammation or ulceration and the conditions are harmless.
Treatment
While commissural pits require no treatment, the lip pits are sometimes surgically excised for cosmetic reasons.
DOUBLE LIP
Double lip is an anomaly characterized by a horizontal fold of redundant mucosal tissue, which is usually located on the inner aspect upper lip, although the lower lip can also be occasionally involved.
Clinical Features
- Double lip can be either a congenital defect or an acquired defect. The condition is visible as a “cupid's bow” when the lip is tense but not when the lip is at rest.
- The defect can occur alone or in association with other anomalies.
- The double lip in association with blepharo-chalasis (dropping of the upper eye lid) and non-toxic thyroid enlargement, are known as Ascher's Syndrome.
Treatment
Although it is excised sometimes for cosmetic reasons, double lip mostly requires no treatment.
FRENAL TAG
Definition
Frenal tag is a redundant piece of mucosal tissue, which projects from the maxillary labial frenum.
Clinical Features
- It is a familial condition and seems to be inherited as autosomal dominant trait.
- The shape and size of frenal tag varies from patient to patient and is clinically asymptomatic.
- Sometimes the condition is mistaken for a fibrous hyperplasia caused by local injury or irritation.
Histology
Histologically frenal tag consists of normal oral epithelium and connective tissue.
Treatment
No treatment is required.
HEREDITARY INTESTINAL POLYPOSIS (PEUTZ-JEGHERS) SYNDROME
Definition
Peutz-Jegher's syndrome is a hereditary condition characterized by mucocutaneous pigmentation and gastrointestinal polyposis.3
The disease is transmitted through an autosomal dominant gene. It is a developmental condition and the primary disorder is not of the melanocyte system.
Clinical Features
- Peutz-Jegher's syndrome begins in infancy and there is no sex predilection.
- There is multifocal melanin pigmentations in the perioral locations, which often manifest as discrete, brown to bluish-black macules on the skin, (size varies from 1 to 5 cm in diameter).
- The macules often group around the oral, nasal and orbital orifaces.
- The pigmentation is most intense at the vermilion border of the lower lip and it often extends to the facial skin as well as the oral mucosa.
- Buccal mucosa is the most frequently involved intra oral site, followed by the palate and gingival, etc. Tongue and floor of the mouth are rarely involved. Sometimes the macules can be seen over the hands and feet.
- The skin pigmentation tends to fade away in adult life, while the mucosal pigmentation persists.
- Besides melanotic pigmentations, Peutz-Jegher's syndrome has the other very important features, which include—intestinal polyposis. The polyps occur throughout the intestine but are more common in the small intesatine (jegunum).
- Presence of these polyps can cause abdominal pain, rectal bleeding and diarrhea.
- Occasionally intussusception and obstruction may cause (even) death.
- The polyps occur either as a hamartomatous growth or as an inflammatory lesion and they may have a very limited neoplastic potential.
Histopathology
Histologic examinations of the oral macular lesions exhibit excessive accumulation of melanin granules in the basal cell layer.
Differential Diagnosis
- Perioral location is unique and often diagnostic.
- Radiographic examinations can be useful for detection of intestinal polyps.
- Genetic counseling.
- Familial history of the diseases also helps in making diagnosis.
Treatment
No treatment is required for these oral and perioral melanotic macules. However, surgical intervention may be required for the intestinal polyps causing intussusception.
ORAL MELANOTIC MACULE (EPHELIS)
Definition
Oral melanotic macule is an idiopathic condition characterized by focal pigmented lesions involving the mucosa.
Clinical Features
- Oral melanotic macule presents a small, flat, brown or brown black asymptomatic lesion. There is no specific age group for their occurrence,
- It is seen commonly on top of the lip (mostly lower lip) near the midline.
- Intraorally gingiva, buccal mucosa and palate are the most frequently involved sites.
- The conditions are asymptomatic and have no malignant potential.
Histopathology
- Microscopically, oral melanolic macules present diffuse accumulation of melanin granules in the basal keratinocytes.
- The lesion does not evolve from proliferation of melanocytes, therefore, they remain normal with no atypia.
- Occasionally, melanin incontinence is observed with pigmented granules being seen in sub epithelial melanophages.
Differential Diagnosis
- Superficial melanoma.
- Blue nevi,
- Amalgam tattoo.
- Addison's disease.
- Peutz-Jegher's syndrome etc.
Treatment
The persistent, innocuous looking lesions do not require any treatment however; biopsy is mandatory for a definitive diagnosis of the condition.
UVULA ELONGATA
Definition
Uvula enlongata is the abnormally long uvula, which touches or hangs lower than the base of the tongue.
Clinical Features
- The condition is usually seen at birth and sometimes it has a familial tendency. It is seen more frequently among females.
- Although it is mostly asymptomatic, some sensitive patients may cough or gag when the elongated uvula touches the epiglottis or the base of the tongue.
- Acquired cases of uvula elongata, may occur as a result of chronic pharyngitis due to cola nut chewing.
Differential Diagnosis
Neoplasm of the uvula.
Treatment
In most of the cases, no treatment is required. However, in symptomatic cases, astringents can be used which will contract the uvula. In more severe cases, amputation is recommended.
CHEILITIS GLANDULARIS
Definition
Cheilitis Glandularis is an uncommon developmental anomaly of the lip characterized by chronic enlargement of the labial salivary glands.
Etiology
- Chronic exposure to sun, wind and dust.
- Use of tobacco.
- Emotional stress.
- Heredity.
Recent investigations indicate that overexposure to sun with superimposed bacterial infection may give rise to this condition.
Clinical Features
- Cheilitis glandularis commonly occurs among middle aged or elderly adults and often there is a male predilection.
- Inflammatory enlargement of the superficial or deep minor salivary glands of the lip often cause multi nodular swelling.
- Lower lip is involved more often than the upper lip and the vermilion border as well as the mucosa can be of normal color.
- However in many cases, the lip shows diffuse keratosis with scaling of the surface.
- The lip is often everted due to swelling of the glands and its surface often reveals multiple pits or fistulas representing dialated and inflamed minor salivary duct openings.
- Exudates may be expressed from these salivary duct openings.
- Few cases of cheilitis glandularis may be transformed into carcinoma of the lip.
Types
Clinically cheilitis glandularis can be of three basic types-
- The simple type
- The superficial suppurative type and
- The deep suppurative type.
The simple type presents multiple, painless, pinhead size lesions on the lip with central depression.
The superficial suppurative type of cheilitis glandularis presents painless swelling of the lip with induration and areas of ulcerations.
The deep suppurtive type is characterized by abscess formation in the lip with fistulas tracts. The disease heals by scarring.5
Histopathology
- The surface epithelium can be either normal or hyperkeratotic.
- The underlying salivary gland tissue shows hypertrophy and inflammation.
- Dysplastic changes can be noticed in some cases.
Treatment
Biopsy is mandatory especially in suspected cases where the lip shows excessive keratosis or ulcerations.
Lesions with premalignant changes should be treated by surgical stripping of the lip without involving the vermillion border to save the esthetics.
CHEILITIS GRANULOMATOSA
Cheilitis granulomatosa is an atypical granulomatous disease of the lip, the origin of which is not clearly understood.
Pathogenesis
The exact cause of cheilitis granulomatosa is not known. Some investigators believe it as a regional form of sarcoidosis. While others suggest it as a granulomatous lesion of allergic origine. The disease may also occur due to hypersensitivity to bacterial toxins in a chronic focus of infection in another nearby location.
Clinical Features
- Children and young adults commonly develop this disease (median age 25 years) and usually there is a female predominance.
- Either upper, lower or both lips show a diffuse, nodular enlargement, which involves the entire lip.
- Generally the lower lip is enlarged on a more regular basis.
- The swelling is usually painless, firm and exhibits no pitting upon pressure.
- There is no sign of inflammation or ulceration on the surface of involved lips.
- Enlarged lips often create some cosmetic problems besides that the patient may also have difficulties during eating, drinking or speaking.
- Few lesions may be present with scaling, fissuring, vesicle or pustule formation at the vermilion border.
- Cheilitis granulomatosa in association with facial paralysis and fissured tongue constitutes the Melkersson – Rosenthal Syndrome.
- Besides lip lesions few other oral lesions can possibly occur like nodular or papillary tumor on the tongue and multinodular lesions or redish or bluish plaques on the buccal mucosa or palate.
Histopathological Features
- Microscopically cheilitis granulomatosa shows granulomatous inflammation with infiltration by chronic inflammatory cells chiefly lymphocytes, plasma cells and histiocytes.
- These noncaseating granulomas often simulate sarcoidosis and these lesions replace the minor salivary glands.
- Generalized edema and dilated blood vessels are present throughout the connective tissue.
Differential Diagnosis
- Sarcoidosis
- Angioneurotic edema
- Edema and cheilitis subsequent to odontogenic infections.
Treatment
- Intralesional injection of steroid (Triamcinolone) may result in reduction in the size of the lesion.
- Surgical excision of the granulomas may be effective but often there is reoccurrence.
- Elimination of odontogenic and periodontal infections may produce reduction in the sign and symptoms of the disease.
ANOMALIES OF THE ORAL MUCOSA
FORDYCE'S GRANULES
Definition
Fordyce's granules are ectopic collections of sebaceous glands, which occur in various locations within the oral cavity.
Clinical Features
- Fordyce's granules are seen at any age and there is no sex predilection.
- They are commonly seen in the upper lip; buccal mucosa, gingiva, anterior pillars of fauces and the lesion usually have a bilaterally symmetrical distribution. Fordyce's granules may occur rarely in the lower lip.
- These glands can also be present in the esophagus, genitalia, nipples, palms and the parotid glands.
- Normally these glands are present in the 60–70 % of adult population but their number varies widely between individuals.
- The number of Fordyce's granules in the upper lip increases during puberty while there is an increase in the number of these glands in the buccal mucosa in the later stages of life.
- Fordyce's granules clinically appear as multiple, small, discrete, milia-like, yellowish structures, which measure about 1 to 2 mm in diameter.
- On occasions, clusters of numerous sebaceous glands may form slightly raised confluent plaques.
Histopathology
- Histologically Fordyce's granules of the oral mucosa are identical to the normal sebaceous glands found in the skin, except the fact that they are not associated with hair.
- These glands are located superficially and are composed of 1 to 5 lobules. They empty into a duct, which opens directly on to the mucosal surface. The duct may show keratin plugging.
- The peripheral cells of the Fordyce's granules are flat and darkly stained, where as the inner cells are lipid rich and pale in appearance.
Differential Diagnosis
The smaller size, multiplicity and typical yellow color are characteristic of the Fordyce's granules and are unlikely to be confused with any other mucosal lesions.
Treatment
No treatment is required for this condition. However, on rare occasions, sebaceous cysts or adenomas may develop from the pre-existing Fordyce's granules.
FOCAL EPITHELIAL HYPERPLASIA
Definition
Focal epithelial hyperplasia (commonly known as Heck's disease) is a condition characterized by multiple papillary or sessile areas of epithelial hyperplasia in the oral mucosa.
Etiology and Pathogenesis
- The disease is specifically found among native American, Indians, Northern native people and other ethnic groups in Europe and Africa.
- The exact etiology of Heck's disease is not known but it is probably caused by the Human Papilloma Virus (HIV) type 13 and 32.
- Similar appearing lesions may also be encountered among HIV-seropositive homosexual males.
Clinical Features
- The disease commonly occurs among children between the ages of 3 to 18 years and there is no sex predilection.
- Clinically focal epithelial hyperplasia presents multiple, small, pedunculated, polypoid or nodular soft tissue growths on the oral cavity.
- Buccal and labial mucosa are the most common sites. However, the disease can also involve the tongue, gingiva and anterior faucial pillars etc.
- Individual lesions measure about 1 to 5 mm in diameter and are either white or pink in color.
- Most of the lesions regress spontaneously after about 4 to 6 months and occasionally few lesions can racur.
Histopathology
- Focal epithelial hyperplasia histologically shows hyperparakeratosis of the covering epithelium with extensive acanthosis (increased thickening of the spinus cell layer).
- The epithelial cells of the upper spinus layer show enlarged nuclei and vacuolated clear cytoplasms (koilocytes).
- Deeper layer of epithelium reveals thickening, elongation and even fusion of the rate-pegs.
- Basal cell layer of the epithelium exhibit increased mitotic activity.
- Occasionally focal areas of liquefaction degeneration of the basal layer may be found.
- The underlying connective tissue is loose, well-vascularized and exhibit variable infiltrates of lymphocytes.
Treatment
Since focal epithelial hyperplasia is a harmless, self-regressing condition, it usually requires no treatment.
WHITE SPONGE NEVUS
Definition
White sponge nevus is a congenital mucosal abnormality, which occurs as an autosomal dominant hereditary disorder and manifests as a white lesion of the oral mucosa.
Pathogenesis
- This condition is transmitted as an autosomal dominant trait with incomplete penetrance and variable expressivities.
- Mutations in the genes coding for keratins 4 and 13 (the pair of keratins expressed by epithelial cells in the mucosa affected by the disorder) have been identified, suggesting the disorder occurs due to a hereditary keratin defect.
- The heaping up of cells on the surface of the epithelium also suggests the possibility of an impaired normal desquamation process of the superficial strata of cells.
Clinical Features
- White sponge nevus has its onset mostly during childhood. Some lesions are congenital and are present at birth while some lesions may even initiate during the adolescent period.
- There is no sex predilection.
- The intraoral lesions are almost always bilateral and are mostly found over the buccal mucosa and tongue. Vestibular mucosa is also sometimes affected.
- Besides oral mucosa, white sponge nevus can be seen on the conjuctivital, oesophageal, nasal and ano-genital mucosa.
- Clinically white sponge nevus presents an asymptomatic, deeply folded white or gray lesion, which affects several mucosal sites.
- The surface of the lesion is soft, uneven and have a shaggy appearance with a spongy consistency.
- The lesions of white sponge nevus can affect several members of the same family.
- The lesions can be either diffuse or patchy and have a translucent opalescence similar to that of leukodema.
- The disease can sometimes present ragged white areas which can be peeled off by gentle rubbing without any ensuing bleeding.
Histopathology
- White sponge nevus histologically shows marked thickening of the epithelium with mild to moderate hyperparakeratinization, acanthosis and spongiosis.
- Marked intracellular edema of the spinus and parakeratinized cell layer of the epithelium is an important characteristic feature of the disease.
- The cells with intracellular edema show vacuolated cytoplasms and shrunken (pyknotic) nuclei.
- Intrestingly under microscope only the cell walls and the pyknotic nuclei at the centers of the cells are visible, which often gives rise to a so called “basket weave” appearance.
- Parakeratin plugging is another important finding in white sponge nevus, which runs from the surface and extends deep into the spinus layer.
- Individual cell kearatinization may be seen in spinus cell layer.
- The basal cells are intact and the lamina propria shows no inflammatory changes.
- There is no evidence that this lesion undergoes malignant transformation.
Electron Microscopic Study
Ultra structural studies of white sponge nevus reveals that some cells of the spinus layer differentiate early and become enriched with tonofilaments.
Differential Diagnosis
Thick, corrugated, diffuse white lesion in the mouth, with history of involvement of several members of the same family is usually suggestive of white sponge nevus.
However the following diseases are to be considered in the differential diagnosis of white sponge nevus.
- Hereditary intra epithelial dyskeratosis.
- Lichen planus.
- Candidiasis.
- Leukodema.
Treatment
DEVELOPMENTAL DEFECTS OF THE GINGIVA
FIBROMATOSIS GINGIVAE
Definition
Fibromatosis gingivae are benign diffuse infiltrative proliferations of fibroblasts and mature collagen fibers within the gingival tissue.
It is a hereditary condition, which is transmitted as an autosomal dominant trait. The disease is probably the result of a developmental abnormality of the fibroblast function.
Clinical Features
- Clinically the disease is characterized by localized or generalized fibrous enlargement of the gingiva.
- The enlargement mostly appears in young children but may be present at birth or even may not be noticed until adult life.
- Both sexes are equally affected by gingival fibromatosis.
- The gingiva shows multinodular enlargements especially in the inter dental papilla regions.
- The gingival tissue changes become obvious soon after the eruption of the deciduous teeth.
- The hyperplastic tissue is firm, painless and retains the normal coral pink color of gingiva.
- Sometimes the markedly enlarged gingiva may cover the entire crown of the erupted teeth. The eruption of teeth is normal.
- Elimination of dental plaque does not make any significant reduction in the severity of the disease.
- Occasionally, the condition is associated with hypertrichosis, epilepsy and mental retardation.
- Gingival fibromatosis can also be associated with other syndromes, e.g. Cowden's syndrome and Rutherfords Syndrome (features of individual syndrome are given in the relevant chapter dealing with syndromes.)
- Moreover, gingival fibromatosis can be a feature of “Laband Syndrome” which is characterized by splenomegaly, enlarged nasal and external ear soft tissue, shortened terminal phalanges, hypermobility of joints and hypoplasia of nails.
- Sometimes symmetrical fibrous overgrowths may occur bilaterally in the maxillary tuberosity region and few of such cases are possibly related to gingival fibromatosis.
Histopathology
Histopathologically gingival fibromatosis presents the following features:
- The covering epithelium is hyperplastic and often exhibits thin elongated rete-pegs.
- The fibrous connective tissue consists mainly of course bundles of collagen fibers with scattered mature spindle shaped fibroblasts few of which are multinucleated.
- Mucoid changes in the gingival connective tissue may occur due to the accumulation of excessive amount of ground substances.
- There is significant number of mast cells associated with the fibroblastic proliferation.
- Histologically, hereditary gingival fibromatosis is indistinguishable from other forms of gingival enlargements including those associated with medications.
Differential Diagnosis
- Phenytonin sodium induced gingival hyperplasia
- Generalized hyperplastic gingivitis.
- Leukemic infiltration of the gingiva.
History of familial involvement is extremely important in making the diagnosis of the disease.
Treatment
Periodic gingivectomy with placement of gingival acrylic splints for cosmetic and functional reasons.
RETROCUSPID PAPILLA
Retrocuspid papilla is a slightly raised area of mandibular alveolar mucosa, which as the name implies, is commonly located lingual to the cuspids.10
- This structure measures about 2 to 4 mm and is often present bilaterally between the marginal gingiva and the mucogingival junctions.
- Retrocuspid papilla is more common among children and it has structural resemblance to the incisive papilla.
- Histologically the papilla represents a focus of fibro-vascular tissue with an orthokeratinized or parakeratinized surface and it usually covers an osseous foramen of a nutrient blood vessel.
DEVELOPMENTAL ANOMALIES INVOLVING THE JAWBONE
AGNATHIA
Agnathia refers to the complete failure of development of the jawbone, involving either maxilla or mandible or even both the jaws. Agnathia is an extremely rare condition, however, often a portion of the jawbone, e.g. premaxilla, condyle, or ramus, etc. can be developmentally missing.
MICROGNATHIA
Micrognathia is an orofacial anomaly characterized by development of jawbone, which are smaller than normal.
Types of Micrognathia
Micrognathia can be of two types
- Pseudo-micrognathia
- True micrognathia
Pseudomicrognathia It is a condition where normal sized jawbone appears to look smaller when compared with the opposing jaw. A jawbone of standard size may appear smaller if the opposite jaw is larger than normal or if it is positioned more posteriorly in relation to the skull.
True micrognathia It is the condition where the jawbone is really smaller than normal and it can be either a congenital or an acquired problem.
The congenital micrognathia may follow a hereditary pattern and it often occurs in association with other congenital diseases such as Pierre Robin Syndrome or congenital heart disease, etc.
Congentially missing premaxilla often leads to maxillary micrognathia and patients with this anomaly shows retracted middle third of the face.
Congenital mandibular micrognathia may occur due to posterior positioning of the condyle in relation to the skull.
Acquired micrognathia mostly occurs due to trauma, severe infections in the orofacial region especially in younger age.
Ankylosis of the temporomandibular joint in young individuals often leads to mandibular micrognathia with retruded chin.
MACROGNATHIA
Macrognathia is a developmental anomaly characterized by an abnomally large jaw. The condition can affect both the jaws at a time but more often it involves either maxilla or mandible.
Types of Macrognathia
True macrognathia When the jawbone is abnormally large in size, in true sense it is called true macrgnathia.
Pseudognathia A normal sized jaw may look larger when the opposing jaw is smaller than normal. This condition is known as pseudo – macrognathia.
Common Causes of True Macrognathia
- Pituitary gigantism It is often associated with abnormally large jawbones. Both jaws are affected in gigantism and the bony overgrowth is proportionate to the generalized increase in the size of the skeleton.
- Paget's disease of bone Paget's disease often causes increase in the size of maxilla, which is directly related to the generalized overgrowth of the cranium.
- Acromegaly Progressive increase in the size of mandible occurs in cases of acromegally.
- Leontasis ossea It is a form of fibrous dysplasia of bone and the disease is often associated with enlargement of maxilla.
- Hereditary causes Mandibular prognathism often occurs hereditarily.
Mandibular prognathism may occur due to anterior positioning of the lower jawbone in relation to the cranium, even though the exact size of the jaw is normal.
However, there are certain factors, which cause mandibular prognathism and thereby resulting in an appearance of mandibular macrognathia.
These factors are as follows:
- Increased height of the ramus.
- Increased length of the body of mandible.
- Increased gonian angle.
- Decreased maxillary length.
- Posterior positioning of the maxilla in relation to the cranium.
- Prominent chin button.
- Varying soft tissue contours.
In case of macrognathia surgical correction (osteotomy) of the abnormally large jaw is often performed for both functional and aesthetic reasons.
FACIAL HEMIHYPERTROPHY
Definition
Facial hemihypertrophy is a developmental condition characterized by significant unilateral enlargement of the face.
Although most humans exhibit some degrees of facial asymmetry only few individuals actually develop facial hemihypertrophy.
Etiology
Although a number of factors have been proposed to explain this condition, the most important one appears to be an increased neurovascular supply to the affected side of the face. Other possible factors include the following:
- Hormonal imbalance.
- Incomplete twining
- Chromosomal abnormality.
- Defective intra-uterine development.
- Lymphatic abnormalities.
Clinical Features
Facial hemihypertrophy clinically exhibits the following features:
- Unilateral enlargement of the facial soft tissues, bones and teeth.
- Either side of the face can be affected and there is a slight female predilection.
- The asymmetry is more specifically noticed in the frontal bone, maxillae, palate, mandible, alveolar process, condyles and the associated soft tissues.
- The skin is thick and coarse on the affected side and also there is presence of thick and abundant hair (hypertrichosis).
- The sebaceous and sweat glands on the affected side show excessive secreations.
- The ear and eye on the affected side may also be enlarged.
- Unilateral enlargement of the cerebral hemispheres may cause mental retardation and seizure in about 15% to 20% cases in patients with facial hemihypertrophy.
- There can be an increased incidence of certain visceral tumors, particularly Wilms tumor of the kidney.
- On rare occasions, the hypertrophy may extend beyond the face and include the limbs or even the entire side of the body.
Oral Manifestations
- Unilateral macroglossia with an increase in the size of the fungiform papilla is often seen.
- On the affected side, the crowns and roots of the teeth, especially the permanent teeth are often enlarged and they may erupt prematurely.
- The jawbone proper is larger and wider on the affected side and because of the osseous and dental asymmetries, melocclusion in common.
- The buccal mucosa on the affected side appears pendulus and velvety.
Differential Diagnosis
- Neurofibromatosis.
- Fibrous dysplasia is of bone.
- Arteriovenous malformations of jaws.
Treatment
No treatment is usually required for facial hemihypertrophy. However selective surgical treatments may be performed to improve functional and cosmetic status wherever necessary.
FACIAL HEMIATROPHY
Definition
Facial hemiatrophy is a developmental anomaly characterized by progressive decrease in the size of one side of the face due to atrophy of the facial structures.
Etiology
The exact etiology of the disease is not known however certain possible factors have been identified which can precipitate the condition. These factors include the following:
- Peripheral nerve dysfunction.
- Trauma
- Heredity
- Peripheral trigeminal neuritis.
- Infection
- Regional systematic sclerosis.
Clinical Features
- The condition usually begins in the first or second decade of life. Many cases may be present since birth.
- Initially a slightly depressed vertical furrow or line is noticed at the midline of the forhead and eyebrow.
- As the condition progresses, facial tissue on the affected side including the skin, subcutaneous tissue, muscle and bone etc become atrophic resulting in facial deformity.
- Usually the left side of the face is involved more often than the other side and the affected side of the face shows hyperpigmentation of skin with loss of hair.
- Severe cases may often result in hollowing of the cheek and depressed eye in the orbit.
- Other features, which may accompany facial hemiatrophy, include Trigeminal neuralgia, contralateral Jacksonian epilepsy and ocular changes.
- The cartilage of the ear, nose and larynx, etc. may be affected.
- Occasionally the disease may affect other parts of the body.
Oral Manifestations
- Delayed development of the jawbone and roots of teeth on the affected side.
- Tooth eruption on the affected side may also be retarded.
Treatment
There is no effective treatment for facial hemiatrophy. Progression of the condition ceases after certain age and it remains static thereafter for the remaining part of life.
CLEFT LIP AND CLEFT PALATE
Definition
Cleft lip It is a developmental anomaly characterized by a wedge-shaped defect resulting from the failure of two parts of the lip to fuse into a single structure. This defect is more commonly seen in relation to the upper lip.
Cleft palate It is a developmental defect of the palate characterized by a lack of complete fusion of the two lateral halves of the palate resulting in a cleft, which communicates between oral cavity and the nasal cavity.
Cleft of the maxillo-facial skeleton are quiet common entities and these can involve many structure of the orofacial region. Major congenital malformations causing clefts in the orofacial region include-cleft lip, clefts of the primary and secondary palate, mandibular cleft, oblique facial cleft, submucos cleft palate, bifid uvula and pits of the lip, etc.13
These developmental defects often have very serious impacts on the growth, development and function the involved facial tissues, in the appearance of the face and finally the personality of the patient as well.
Etiology
The etiology of cleft-lip and cleft palate involves both hereditary and environmental factors.
Hereditary Factors
Heredity is the most important single factor in the development of cleft lip and cleft palate. Different studies indicate that nearly 40% of cleft lip cases with or without cleft palate are hereditary in origin. Here dity also plays role in the development of about 20% cases of isolated cleft palate.
Moreover research also indicates that cleft lip or cleft palate of hereditary origin can occur either due to polygenic influence or due to monogenic influence.
Polygenic inheritance of cleft lip or cleft palate If the origin of the disease is influenced by several different genes acting together it is known as polygenic inheritance. It is presumed that every individual carries some genetic liability for clefting and only if the combined liabilities of both the parents exceed a minimum threshold level, then clefting will occur in their offsping.
Monogenic inheritance of cleft lip and cleft palate When clefting is influenced by only a single gene it is called monogenic defect. Cleft lip and cleft palate cases can be associated with numerous syndromes and this type of conditions are often monogenic in origin.
Environmental Factors
Several environmental factors have been identified which play probably an accessory role in the development of cleft lip and cleft palate.
The factors include the following:
- Nutritional factors such as deficiency of or excess of vitamin A and deficiency of riboflavin.
- Psychologic, emotional or traumatic stress in pregnant mother.
- Relative ischemia to the area due to defective vascular supply.
- Mechanical obstruction by enlarged tongue.
- High dose of steroid therapy during pregnancy.
- Localized mucopolysaccharide metabolism defect in the area.
- Infections.
- Substances such as alcohol, drugs or toxins in the circulation.
- Pathological conditions like Streeter's fetal dysplasia.
- Lack of inherent developmental force.
Pathogenesis of Cleft Lip and Cleft Palate
Cleft lip and cleft palate usually develop due to incomplete obliteration and maturation of different embryonic processes, which are concerned with the formation of normal lip and palate.
- Mandibular cleft (lower lip and/or mandibular bone) usually occurs either due to failure of the copula to form the mandibular arch or due to persistence of the central groove of the mandibular process. Mandibular clefts are mostly midline defects.
- Cleft of the upper lip and premaxilla occur due to failure of mesodermal penetration and subsequent obliteration of the ectodermal grooves between the median nasal process, lateral nasal process and the maxillary process.
- Isolated cleft of the palate develops due to the failure of fusion between two palatal shelves in the midline.
A number of both genetic and environmental disturbances have been isolated, which can cause breakdown of the normal series of interdependent events or steps during the development of facial structures and resulting ultimately in cleft formation.
- Disturbed mesenchymal cell migration and/or proliferation Failure of fusion of facial growth centers or palatal processes due to impaired mosenchymal cell replacement after palatal fusion.
- Suppressed cell division in associated structures Reduced growth of cranial and/or Meckel's cartilages.
- Impaired intrinsic tissue function Reduced tongue mobility and delayed ability or inability of palatal processes to elevate.
- Disturbance of inductive tissue interactions Aberrant message leading to failure of palatal fusion.
- Suppressed programmed epithelial cell death following fusion Incomplete palatal fusion or reopening of fused processes.
Incidence
Incidence of cleft lip and/or cleft palate is about 1 in 800-child births. It is interesting to note that when a couple have their first baby born with the defect of either cleft lip or cleft palate or both, their second baby will carry a 1% risk of having the same defect.
The defect of cleft lip and cleft palate are on the rise in modern age since the modern maxillofacial and plastic surgery can provided hugely improved and almost perfect esthetic rehabilitation to those patients having cleft lip or cleft palate.
After the perfect surgical repair, the grown up people will never have any problem in free social mixing. Therefore, marriages between these people who are genetically harboring such defects will further bring people having more and more chance of cleft lip and cleft palate.
Classification of Cleft Lip and Cleft Palate
- Unilateral incomplete cleft of the primary palate.
- Complete cleft of the primary palate, ending at the incissive foramen.
- Bilateral complete cleft of the primary palate.
- Incomplete cleft of the secondary palate
- Complete cleft of the secondary palate—soft and hard palates.
- Unilateral complete cleft of the primary and secondary palates.
- Bilateral complete cleft of the primary and secondary palates.
- Incomplete cleft of the primary palate and incomplete cleft of the secondary palate.
Besides these major forms of common facial clefts mentioned above, there are many so called microforms of clefting occurring in the oral cavity, which are often over looked. These conditions are as follows. Cleft uvula, pits and linear indentation of the lip and submucous cleft palate (confined to the bone of hard palate, the mucosa remaining intact).
Common Syndromes Associated with Cleft Palate
- Pierre-Robin syndrome.
- Goldenhar syndrome.
- Median cleft face syndrome.
- Oral facial digital syndrome.
- Apert's syndrome.
- Cleidocranial dysplasia.
- Schenthaner-Marie-Sainton syndrome
- Nagar syndrome.
- Elashy-Waters syndrome.
- Crouzon syndrome.
- Larsen syndrome.
- Treacher-Collins syndrome.
- Marfan syndrome.
- Otopalatodigital syndrome.
- Down syndrome.
- Edwards syndrome.
Clinical Features of Cleft Lip and Cleft Palate
- These defects occur more commonly among male people.
- Clefting involves left side of the face more often than the right side.
- As cleft palate creates a communication between the oral and the nasal cavities, patients often feel difficulty in taking foods and drinks due nasal reflux or regurgitation.
- Breastfeeding is impossible to babies having cleft lip or cleft palate, as they cannot generate sufficient suction.
- Upper anterior teeth may be misplaced, deformed or impacted.
- Retrusion of maxilla with narrow arched palate.
- Maxillary canine or premolars on the affected side may contact in lingual occlusion to the corresponding mandibular teeth due to retrusion of the maxillary bone.
- Increased susceptibility to middle ear infections via the auditory tube.
- Difficulty is phonation and articulation of speech.
- Mental trauma to the child due to the unusual appearance as well as due to the speech problems, which prevents them from mixing with other children freely.
- Improper or untimely correction of these defects may also cause persistence of some ugly appearance and moreover it may result in unbalanced growth of the mid face region.
Treatment
- Cleft lip is treated surgically in the first week after birth when the blood hemoglobin level is high and the kid is protected by his or her maternal antibodies.
- Sometimes the surgery may be deferred until the baby attains 2 to 3 months of age, as by this time, the infant has become adapted to its independent existence.
- Generally cleft palates are corrected surgically at the age of 18 months or immediately after that. This particular time is selected since after this age there will be development of speech and any further delayed in treatment will cause abnormal speech development.
- Familial, social and psychological support is necessary during the protracted management.
- Obturators may be given in untreated adult patients with palatal clefts. The appliance helps in keeping the palatal clefts closed.
DEVELOPMENTAL ANOMALIES OF THE TONGUE
AGLOSSIA
Aglossia is an extremely rare congenital defect characterized complete absence of the tongue. This condition is usually associated with other serious developmental defects in the body.
MICROGLOSSIA
Microglossia is another rare congenital anomaly in which only a tiny or rudimentary tongue has developed from the cupola. Although microglossias may develop as isolated cases but in most cases they occur in association with other congenital anomalies like oromandibular limb hypogenesis syndrome or hypoglossia-hypodactylia syndrome, etc.
- Microglossia without limb deformity can occur but they are also associated with some other birth defects such as partial anodontia, sublingual gland hypertrophy and dextrocardia etc.
- For obvious reasons, patients with microglossia often have severe speech difficulties as well as difficulty in taking food.
- As the size of the tongue often determines the growth and size of the mandibular arch, in case of microglossia the length of the mandibular arch will be smaller due to the smaller size of the tongue.
MACROGLOSSIA
Macroglossia is a relatively common condition characterized by an increase in the size of tongue.
Macroglossia can be either congenital or acquired (secondary) in nature.
Causes of Congenital Macroglassia
- Overdevelopment of the tongue musculature.
- Lysosomal storage diseases:Hurler syndromeHunter syndromeMaroteaux-Lamy syndrome.
- Down syndrome
- Beckwith's hypoglycemic syndrome.
- Multiple endocrine neoplasia syndrome.
Causes of Acquired (secondary) Macroglossia
Tumors in the tongue Lymphangioma, hemangioma and neurofibroma, etc.
Amyloidosis With diffuse deposition of amyloids in the tongue.
Endocrine disorders Acromegaly and Cretinism.
Lymphatic obstruction in the tongue By any malignant tumor.
Cystic lesions in the tongue Epidermoid cyst and dermoid cyst.
Relative Macroglossia
Relative macroglossia is a condition in which a normal sized tongue appears abnormally large if it is particularly enclosed with in a small oral cavity. It happens in cases of maxillary retrution or in cases of restricated nasopharynx.
Lymphangioma restricted to the tongue or in continuity with a cystic hygroma of the neck is the most common cause of macroglossia.
Apparent Macroglossia
Apparent macroglossia is a condition where the tongue appears abnormally large due to poor muscular control of the tongue, although there is no real increase in the bulk of the tongue tissue. Apparent macroglossia is often seen in cretinism and in “Happy puppet” syndrome.
Clinical Features
- Macroglossia of either congenital or acquired type may cause displacement of teeth and malocclusion due to pressure on the teeth by the enlarged tongue.
- It may disturb the process of speech and food intake to some extent.
- Some macroglossia may cause cosmetic deformity.
- There is often indentations or scalloping of teeth on the lateral margins of the tongue.
- Children with macroglossia often develop tongue-thrusting habits, which may lead to bite problems.
- Macroglossia developing in adult people (as in acromegaly or in tumors etc.) may produce spacing of teeth and distortion of the mandibular arch.
- Blockage of the pharyngeal airway due to macroglossia may result in a condition called “obstruction sleep apnea”, which is characterized by intermittent cessation of respiration associated with regular sleep or a pattern of hypersomnolence.
- Macroglossia can also be an important component of “Beckwith's hypoglycemic syndrome, the other features of the syndrome include—neonatal hypoglycemia, mild microcephaly, umbilical hernia, high birth weight and postnatal somatic gigantism.
It is important to note that CT scans can be helpful in determining if the tongue size is normal or there is any deviation.
Treatment
- Removal of the primary cause whenever possible.
- Surgical reduction or trimming may be required when macroglossia disturbs the oropharyngeal function or is causing some major cosmetic problems.
ANKYLOGLOSSIA
Definition
Ankyloglossia can be defined as a developmental condition characterized by fixation of the tongue to the floor of the mouth, causing restricted tongue mobility.
Complete ankyloglossia is an extremely rare condition, however partial ankyloglossia, which is otherwise known as “tongue tie” is a common developmental error of the tongue. The tongue-tie occurs either due to a short lingual frenum or due to a frenum, which attaches too near to the tip of the tongue.17
Ankyloglossia is almost always a congenital disorder and its prevalence rate ranges from 0.04 to 6.8 percent. According to few investigators this condition may sometimes develop as a result of trauma.
Clinical Features
- Ankyloglossia affects male people more frequently than females.
- Although most affected individuals can perform tongue functions almost normally, the restricted tongue mobility in ankyloglossia may sometimes cause the following problems—
- Speech disorders: patient cannot properly pronounciate certain consonants and diphthongs.
- Deformities in dental occlusion
- Difficulty in swallowing
- Tension in the anterior lingual gingiva in tongue-tie may initiate some localized gingival or periodontal diseases near the site of frenal attachment.
- Ankyloglossia may occur sometimes in association with the following syndromes-
- Ankyloglossum spurious syndorme.
- Van-der Woudes syndrome
- Fraser's syndrome
- Rainbow's syndrome
- Orofacial digital syndrome, etc.
Treatment
Partial ankyloglossia in most of the cases does not require any treatment, however in severe cases of partial or complete ankyloglossia, surgical repositioning of the lingual frenum is done to free the tongue.
CLEFT TONGUE
Developmental disturbance may sometimes cause partial or complete cleft in the tongue, although a completely cleft or bifid tongue is a rare congenital anomaly however, a partially cleft tongue is more frequently encountered.
Cleft tongue usually develops due to partial or complete failure of union between the two lateral lingual swellings during embryogenesis.
Partial cleft tongue clinically exhibits a deep groove in the midline, while the bifid tongue shows a complete cleft along its long axis. Cleft tongue in most of the cases is an asymptomatic condition although sometimes irritation can be felt due to deposition of food debris or microorganisms at the base of the cleft.
Sometimes, cleft tongue may occur as a feature of the oro-facial-digital syndrome, other features of this syndrome include frontal bossing, short upper lip with cleft, presence of thick fibrous brands in the lower anterior mucobuccal fold eliminating the sulcus. Cleft of the mandibular alveolar process, etc.
FISSURED TONGUE (SCROTAL TONGUE)
Fissured tongue is a congenital developmental malformation, which manifests clinically as numerous small furrows or groves on the dorsal surface of the tongue.
- The exact etiology for this condition is not known however, ganetic defect, vitamin deficiency or trauma etc. are often suspected to be responsible for the development of fissured tongue
- Usually there is no clinical symptom in fissured tongue but collection of food debris and microorganisms in the fissures or groves may sometimes cause discomfort.
- The fissures or groves often radiate from a central groove on the dorsal surface in an oblique direction.
- As the condition is rare among elderly people than children, there is considerable amount of doubt regarding its supposed congenital developmental nature.
- The incidence rate of fissured tongue is about 7% and there is no sex predilection.
- The disease often occurs in association with Melkersson-Rosenthal syndrome and some investigators believe that fissured tongue can be a feature of benign migratory glossitis.
MEDIAN RHOMBOID GLOSSITIS
Definition
Median rhomboid glossitis is an asymptomatic, elongated, erythematous patch of atrophic mucosa on the middorsal surface of the tongue.18
Etiopathogenesis
In the past median rhomboid glossitis was thought to represent a developmental defect of the tongue, presumably arising as a result of persistence of the tuberculum impar on the surface of the dorsum of the tongue.
During normal embryognesis however the tuberculum impar should retrude and is overgrown by the lateral lingual swellings. In recent times however several investigators believe that median rhomboid gloositis occurs due to chronic infection by candida albicans.
Clinical Features
Incidence The average frequency of median rhombiod glossitis is about 0.2 percent among the general population.
Age The condition is mostly seen among adults and is rarely found among children.
Sex Median rhomboid glossitis is seen more frequently among males.
Site The lesion is located immediately anterior to the foramen cecum and the circumvallate papillae in the midline on the dorsurm of the tongue.
Presentation
- The median rhomboid glossitis starts as a narrow, mildly erythematous area located along the median fissure of the tongue.
- The lesion is asymptomatic and it enlarges slowly, often remaining unnoticed by the patient for many years.
- The filly developed lesion of median rhomboid glossitis appears as a diamond or lozenge shaped area devoid papilla.
- The color of the lesion varies from pale pink to bright red and occasionally there is presence of a white halo.
- The surface is usually smooth, flat or slightly raised and is sometimes fissured or lobulated.
- In many cases, the lesion exhibits an erythematous and nodular hyperplasia characteristic of chronic hyperplastic candidiasis.
- Some patients even develop a similar lesion on the midline of the palate just opposite the tongue lesion.
- Median rhomboid glossitis is usually asymptomatic but occasionally it may cause slight soreness or burning sensation.
- The lesion is clinically suspicious and it is often mistaken for carcinoma of the tongue. (Although the typical location of median rhomboid glossitis is not a frequent site for the carcinoma of the tongue).
- In some cases the disease may regress spontaneously.
Differential Diagnosis
- Squamous cell carcinoma
- Granular cell myoblastoma.
Histopathology
Microscopically median rhomboid glossitis presents the following features:
- Mild to severe parakeratosis of the surface epithelium.
- Loss of papilla.
- Thinning of the supra-papillary epithelium.
- There may be presence of acanthosis with elongation of rete-ridges, which may either divide or anastomose.
- Superficial layer of the epithelium often shows neutrophilic infiltration, and often there is presence of candidal hyphae.
- The underlying connective tissue is usually very vascular and is infiltrated by chronic inflammatory cells.
- On occasions the epithelium may show features of dysplasia.
Treatment
No treatment is basically required for this lesion. Antifungal agents and antiseptic gurgles are used during irritation in the area.
LINGUAL VARICES
Definition
A varix is a dilated, tortuous vein, which is often subjected to increased hydrostatic pressure but is poorly supported by the surrounding tissue.
Clinical Features
- Varicosities can be observed in many oral locations like ventral surface of tongue, floor of the mouth, lips, buccal mucosa and the commissures etc.
- Among all these intraoral locations, ventral surface of tongue and floor of the mouth are the most common sites for oral varices.
- Clinically lingual varices appear as small, round, purplish nodules lateral to the sublingual vein, which is usually also deflected.
- Lingual varices are common among people over the age of fifty and they tend to become more conspicuous with advancing age.
- Thrombosis can occur occasionally in these varicose veins, however only rarely there are any clinical symptoms.
- Presence of lingual varices before the ages of 50 indicate premature ageing.
- Lingual varices may occur in association with leg varicosities, however there is no relationship established between cardiopulmonary disorder and lingual varices.
- Sometimes lingual varices can be indistinguishable from hereditary hemorrhagic telangiectasia, however the absence of skin and mucosal lesions and absence of bleeding tendency in lingual varices usually helps to establish the proper diagnosis.
Treatment
No treatment is required for lingual varices.
GEOGRAPHIC TONGUE
Definition
Geographic tongue is the multifocal, patchy irregular area of depapillation of tongue characterized by frequent remissions and recurrences.
Etiology
The exact etiology of geographic tongue is not known, patients often have a positive family history of the similar problem. However, many investigators believe that emotional stress may precipitate this condition.
Clinical Features
- The condition occurs in about 1 to 2 percent of the population.
- It can be seen among children as well the adults and there is a slight female predilection
- Geographic tongue clinically presents multiple, irregular, well-demarcated, patchy erythematous areas on the dorsum of the tongue with desquamation of the filliform papilla.
- At the periphery, these lesions are often surrounded by a well-defined, slightly raised, yellowish-white, serpigenous line.
- Although the filliform papillae are absent in the desquamated zone, the fungiform papillae remain present, which appear as few red dots, projecting from the surface.
- The lesions heal centrally and spread centrifugally, and they may even sometimes involve the ventral surface of the tongue.
- Remissions of the initial lesions are always followed by fresh recurrent lesions, which involve newer areas of the tongue surface.
- The apparent migration of the lesion from one area to the other and the typical geographic appearance of the condition have led to its typical descriptive terminology.
- Geographic tongue is mostly a painless, asymptomatic condition, however on few occasions it may produce soreness or burning sensation (glossodynia).
- These lesions may occur in association with scrotal tongue.
Histopathology
- Geographic tongue microscopically shows hyperparakeratinization of the covering epithelium of tongue with loss of filliform papilla.
- Intercellular edema and accumulation of neutrophil polymorphs (so called spongiotic abscess) is often seen in the superficial layers of the epithelium.
- Mild inflammatory cell infiltration is present in the underlying connective tissue.
- The condition is histologically similar to hyperplastic candidosis, however candidal hyphae are absent.
Differential Diagnosis
- Psoriasis
- Reiter's syndrome
- Chronic hyperplastic candidosis
- Familiar dysautonomia.
Treatment
There is no specific treatment for geographic tongue. Heavy doses of vitamins may produce some results in few cases.
HAIRY TONGUE
Definition
Hairy tongue is an unusual condition, which occurs due to hypertrophy of the filliform papilla of tongue along with loss of normal desquamation process. This eventually leads to the formation of a pigmented, thick, matted layer on the tongue surface heavily coated with bacteria and fungi.
Pathogenesis
- Normally the keratinized surface layers of the tongue papillae are continuously desquamated through friction of the tongue with food, the rough surface of the palate and the upper anterior teeth. Following desquamation, tongue papillae are replaced by newer epithelial cells from below.
- Lack of tongue movements due to local or systematic disease disturbs the regular desquamation process of the tongue papilla, especially the filliform papilla, which lengthens and produces a hairy appearance on the tongue surface.
- Such hypertrophied papillae are often coated with microorganisms and become discolored by retaining pigments from foods, medicines and chromogenic bacteria, etc.
Clinical Features
- Hairy tongue commonly affects the mid dorsum of the tongue.
- Hypertrophy of the filliform papilla produces a thick matted layer on the dorsal surface.
- Hairy tongue in extreme cases may produce a thick, leathery coating on the tongue surface and this condition is often known as earthy or encrusted tongue.
- Hypertrophied filliform papilla often brushes soft palate and produce gagging sensations.
- Hairy tongue in many cases produces halitosis.
- There can be irritation to the tongue due to accumulation of food debris and microorganisms.
- Hairy tongue is often considered as the mirror of general health status since it is often associated with various systemic diseases.
Treatment
- Cleaning and scraping of the tongue.
- Application of topical keratolytic agents.
- Consumption of yogurt.
- The affected tongue papilla often rapidly returns to normal when long-term antibiotics or other drugs are discontinued.
LINGUAL THYROID NODULE
Definition
Accessory accumulation of functional thyroid gland tissue within the body of the tongue is called lingual thyroid nodule.
Pathogenesis
Embryologically thyroid gland develops as an endodermal downgrowth at the site of the foramen cecum. It then migrates inferiorly along the thyroglossal tract to its ultimate destination in the anterolateral surface of the trachea of the anterior neck. If all or part of the thyroid analogue fails to migrate, then lingual thyroid nodule develops, which is characterized by a mass of thyroid tissue on the mid-posterior dorsum of the tongue. Lingual thyroid nodule therefore represents a thyroid remnant in the site of the thyroid gland's origin.
Clinical Features
- Lingual thyroid nodule is predominantly seen in females and it becomes clinically apparent usually during puberty or adolescence.
- In the tongue, thyroid tissue appears as a nodular exophytic mass, measuring about 2 to 3 cm in diameter and is located posterior to the foramen caecum.
- Sometimes it can also be present as a smooth cystic swelling.
- Symptoms many vary, which include change of voice (dysphonia) bleeding, pain, difficulty in swallowing (dysphagia), respiratory obstruction (dyspnea) and a feeling of tightness in the throat.
Histopathology
- Histologically most of the cases of lingual thyroid nodules are composed of normal mature thyroid tissue, although embryonic or fetal thyroid gland tissues may also be seen.
- Occasionally, thyroid nodules may exhibit colloid degeneration or goiter.
- Microscopic examination of human tongues removed at autopsy reveals remnants of the thyroid tissue within the tongue in as many as 10% cases, although there was no clinically evident thyroid nodule among them.
Differential Diagnosis
- Thyroglossal tract cyst.
- Neoplasms
Diagnosis
Diagnostic procedures include
- Iodine-131 and technetium scans.
- Preoperative biopsy from the thyroid nodule
Treatment
Surgical excision.
Before excision of a lingual thyroid nodule is planned, it must be determined if the patient has a normal functioning thyroid gland in the anterior neck with sufficient secretion to support the daily requirements when the supplementary source in the tongue is removed.
Lingual thyroid nodules can be excised only if a normal thyroid gland is present in the neck. If the secretion from the thyroid gland in the neck is subnormal, then thyroid replacement therapy may be required.
THYROGLOSSAL TRACT CYST
Definition
The thyroglossal tract cyst is an uncommon developmental cystic lesion arising from the embryonic remnants of the thyroglossal tract and it develops in the midline of the neck, anywhere between the base of the tongue above and the thyroid gland below.22
Origin
- The thyroglossal tract cyst arises from the remnants of the embryonic thyroglossal tract, which has not become obliterated.
- Initiation of the process of cyst development is triggered by infection of the lymphoid tissue in the area of the remnants through drainage from upper respiratory tract infection.
- The cyst can arise anywhere along the length of the thyroglossal tract, which extends from the foramen cecum of tongue to the thyroid gland; however most of the cysts (70 to 80% cases) develop below the hyoid bone, where the tract makes two distinct turns on its way to the thyroid gland.
Clinical Features
- The cyst occurs primarily in children and young adults.
- It presents a slow enlarging, asymptomatic mobile swelling involving the midline of the anterior neck above the thyroid gland.
- The firm cystic mass may vary in size from a few millimeters to several centimeters.
- When seen in the region of the tongue, it appears as a dome-shaped compressible lesion.
- A small percentage of these cysts can occur within the tongue and these lesions may produce dysphagia.
- If infected or inflamed a draining fistula may develop, which communicates between the cyst and the overlying skin surface.
- Neoplasms including carcinomas have been reported to develop from the cysts.
Histopathology
- The cyst is usually lined by stratified squamous epithelium or ciliated columnar epithelium or transitional epithelium or a mixture of any of these epithelial types.
- The lining epithelium of the cyst often occurs in association with follicles of the glandular thyroid epithelium.
- Lymphoid aggregates, thyroid tissue, mucous glands and sebaceous glands, etc. are often present within the capsule of thyroglossal tract cyst.
- In some cases the lining epithelium of the cyst or the remnants of the thyroglossal tract may undergo malignant transformation and results in the development of carcinoma.
Differential Diagnosis
- Lingual thyroid nodule,
- Mesenchymal neoplasms
- Dermoid cysts
- Epidermoid cysts.
Treatment
Thyroglossal tract cyst should be surgically excised along with the tract. Rate of recurrence is very high. To minimize the recurrence of the cyst involving the hyoid area, it is sometimes recommended that the central portion of the hyoid bone and its associated remnants of thyroglossal tract be removed.
ANOMALIES OF ORAL LYMPHOID TISSUE
Reactive Lymphoid Aggregate
The oropharyngeal lymphoid tissue is primarily distributed in a circular arrangement called the “Waldeyer ring” in the posterior region of the mouth. It consist of three main masses of lymphoid tissue namely the paired palatine tonsils, the pharyngeal tonsils (adenoids) and the lingual tonsils.
Besides this, lymphoid tissues may also be found in a variety of intraoral locations like the buccal mucosa, soft palate, floor of the mouth and gingiva etc.
Reactive hyperplasias may occur in lymphoid tissue in any of these locations. Lingual tonsil is one of the largest oral lymphoid aggregates and its common location is the posterior part of the tongue. It may extend anteriorly up to the region of the foliate papilla and reactive lymphoid hyperplasia of the lingual tonsil in this location is sometimes termed as ‘foliate papillitis’.23
When inflamed, the lingual tonsils produce swelling, erythema of the overlying mucosa and pain or discomfort, especially during swallowing. There can be diagnostic confusion if the involvement is unilateral rather than bilateral.
Sometimes, children and adolescents may have islands of extra pharyngeal lymphoid tissue called ‘oral tonsils’ on either side of the lingual frenum and they appear as discrete, slightly elevated, reddish plaques in the floor of the mouth.
Oral tonsils consist of lymphoid aggregates, which exhibit germinal centers surfaced by non-keratinized squamous epithelium with or without occasional crypts. It must be remembered that lymphoma the malignant neoplasm of the lymphoid tissue origin, can develop from any of the lymphoid tissue aggregates found in the oral cavity.
LYMPHOEPITHELIAL CYST (BRANCHIAL CYST)
Definition
Lymphoepithelial cyst is the term used to describe cystic lesion previously classified as branchial cyst. It is a developmental cyst with an uncertain pathogenesis.
Clinical Features
Age Lymphoepithelial cysts occur during late childhood or early adulthood.
Sex It occurs more frequently among males than females.
Site Lateral aspect of the neck anterior to the sternomastoid muscle.
Oral lymphoepithelial cysts are uncommon lesions but whenever they occur, these lesions involve floor of the mouth in 50% cases; and ventral and posterolateral surface of tongue in 40% cases. Other sites involved may be the soft palate, mucobuccal fold and anterior faucial pillars.
Clinical Presentation
- Lymphoepithelial cyst generally presents as an asymptomatic, circumscribed, movable swelling on the lateral aspect of the neck anterior to the sternomastoid muscle.
- Intraorally it commonly appears as a small, slow enlarging, elevated, yellowish-pink nodule.
- The cysts may be unilateral or bilateral and may be tendered on palpation.
- A draining fistula may develop, which communicates between the cyst and the overlying skin surface.
- The size of the cyst ranges from few millimeters to 1.5 to 2 cm in diameter.
- Recent reports indicate that there is a marked increase in the incidence of lymphoepithelial cyst of the major salivary glands, among patients those who are tested positive for HIV.
Histopathology
- Histologically the lesion consists of a cystic cavity lined by thin stratified squamous epithelium.
- The cyst is generally embeded in a circumscribed mass of lymphoid tissue, which typically exhibits discrete follicles of the lymph node pattern.
- The capsule of the cyst also presents variable amount of connective tissue, being infiltrated by lymphocytes, plasma cells. macrophages and occasional multi nucleated giants cells.
- Cystic lumen is filled up with either a thin watery fluid or a thick gelatinous material containing desquamated orthokeratin, sloughed epithelial cells and lymphocytes etc.
Pathogenesis
- Lymphoepithelial cyst is probably derived from epithelium entrapped within lymphoid tissues of the neck, during embryologic development of the cervical sinuses or second branchial clefts or pouches.
- An alternate theory suggests that the epithelium in lymphoepithelial cyst might be derived from the ductal epithelium of salivary glands, which remained entrapped within the cervical lymph nodes during embryogenesis.
Differential Diagnosis
Lymphoepithelial cyst should be differentially diagnosed from:
- Inflammatory lesions.
- Teratoma
- Warthins tumor
- Dermoid cyst
- Neoplasms of the minor salivary gland.
- Salivary lymphoma.
Treatment
The intraoral counterpart of lymphoepithelial cyst is treated by conservative surgery. Recurrence is usually rare.
ANGIOLYMPHOID HYPERPLAISA WITH EOSINOPHILIA (ALHE)
Definition
This is a benign condition characterized by subcutaneous nodular aggregates of lymphocytes and eosinophils, regional lymphadenopathy and peripheral blood eosinophilia.
Similar findings were also noted under the heading of Kimura's disease, characterized by eosinophilic grannuloma of soft tissue and eosinophilic lymphofolliculosis. However, unlike angiolymphoid hyperplasia with eosinophilia, Kimura's disease has a distinct male predilection and is not associated with regional lymphadenopathy.
Etiology:
- A vascular proliferation along with intense inflammatory cell infiltration in the lesion suggests a reactive etiology for this condition.
- A reactive immune cause has also been suggested as the disease shows increased serum IgE levels and deposition of IgE within the lymphoid follicles.
- According to some investigators, candida albicans might be having some role in the initiation of this disease. Since anticandida albicans antibody can be demonstrated within the lesion and moreover, the condition improves after hyposensitization to these allergen.
Clinical Features
Age Mean age of occurrence is about 35 years.
Sex More common among males.
Site Although 85% of the lesions usually occur in the head and neck area, oral lesions one rare.
Lower lip is the commonest site.
Presentation
- The lesion clinically presents a slow enlarging, painless submucosal nodule.
- It measures about 1.5 cm in diameter and is movable.
- In about 40% cases eosinophilia is detected in peripheral blood examination.
- Some of the patients may exhibit multiple lesions in the oral cavity.
Histopathology
- Microscopically angiolymphoid hyperplasia with eosinophilia reveals a circumscribed lesion, which is grossly separable from the surrounding tissue.
- A nodular mass of hyperplastic lymphoid tissue is seen with well – defined lymphoid follicles.
- Patchy areas of inflammatory infiltrates comprising of lymphocytes, eosinophils and macrophages are seen.
- Proliferating blood capillaries with plump endothelial cells are often noticed within the inflammatory zone.
Differential Diagnosis
- Minor salivary gland neoplasm.
- Mucocele
- Lipoma
- Schwannoma
- Eosinophilic granuloma
Treatment
- Surgical excision
- Intra lesional steroid therapy may produce some response.
- Recurrences are few.
ANOMALIES OF THE SALIVARY GLAND
Developmental anomalies of the salivary glands are extremely rare entities and the lesions include the following:
- Aplasia (agenesis) of the salivary gland.
- Hypoplasia.
- Aberrant salivary gland.
- Atresia.
- Accessory ducts.
- Diverticuli.
- Lingual mandibular salivary gland depression.
APLASIA OR AGENESIS OF THE SALIVARY GLAND
Definition
Congenital absence of the salivary glands (both major and minor glands) due to complete failure of their development or genesis is called salivary gland aplasia.
Clinical Features
- It is an exceptionally rare anomaly in which either a single gland or multiple glands can be involved either unilaterally or bilaterally.
- In some patients, salivary gland aplasia may occur alone, however in other patients this condition is associated with some congenital facial malformations.
- The anomaly may affect several members of the same family.
- Aplasia of the major salivary gland commonly produces xerostomia (dryness of mouth) due to lack of production of saliva in the oral cavity.
- Patients with xerostomia often have difficulty in taking food and they also have increased incidence of caries often resulting in early tooth loss.
- Clinically the oral mucosa appears dry, smooth or pelbby and it shows areas of food accumulation.
- Cracking of the lips and fissuring at the angle of the mouth are commonly seen.
- Congenital aplasia of the salivary glands may be associated with hereditary ectodermal dysplasia, mandibulofacial dysostosis, congenital aplasia of the lacrimal glands and hemifacial microsomia etc.
Treatment
Patients with congenital salivary gland aplasia will require continuous dental supervision and administration of systemic or topical fluorides to prevent dental caries.
HYPOPLASIA OF THE SALIVARY GLANDS
Relative underdevelopment of the salivary gland is known as salivary gland hypoplasia. Hypoplasia of the salivary glands may occur either due to their congenital absence or due to atrophy of the gland secondary to lack of neuromuscular stimulations.
Salivary gland hypoplasia is often associated with Melkersson-Rosenthal syndrome, which consists of cheilitis granulomatosa, facial paralysis and fissured tongue.
According to some investigators, salivary gland hypoplassia may occur secondary to hereditary ectodermal dysplasia.
The clinical features of salivary gland hyplasia are the same as seen in salivary gland aplasia but the features are comparatively less severe in nature. It is important to note that hypertrophy of the salivary glands may occur sometimes as congenital anomaly and it is often associated with a fibrocystic disease called mucoviscidosis.
ECTOPIC SALIVARY GLANDS (ABERRANT)
Definition
The occurrence of normal salivary gland tissue in anatomically unusual locations is known as salivary gland ectopia and such glands are known as ectopic salivary glands.
- Besides the major salivary gland tissues, which are having their specific sites of occurrence, there are several other minor salivary glands located thoughout the oral cavity including the palate, lips, cheek, floor of the mouth, retro molar area and tongue, etc.
- Therefore it is important to know that ectopic salivary glands are those salivary gland tissues, which are found beyond these normal anatomical locations.
- Sometimes the salivary gland tissue may be present within the body of the mandible and in such cases the intraosseous gland maintains a communication with the extra osseous normal salivary gland with the help of a stalk, which has perforated through the lingual cortical plate of bone.
- Majority of the Stafne's bone cysts and the intraosseous salivary gland tissue within the body of the mandible may occur as part of the phenomenon called lingual mandibular salivary gland depressions.
- Ectopic salivary gland tissues may be found in the gingiva and these tissues may produce a tumor-like mass, which is known as gingival salivary gland choristoma.
- Sometimes the ectopic salivary gland tissue may occur within the masseter muscle. Moreover ectopic salivary glands can also be found in the upper portion of the neck in the region of branchial cleft.
- The ectopic salivary glands despite having their various locations intraorally and extraorally, always histologically exhibit normal salivary gland lobules and ducts.
- Pathological conditions like sialolithiasis, neoplasms and cysts, etc. which commonly affect the normal salivary gland can also involve the ectopic salivary gland tissues.
- Intraosseous ectopic salivary glands any sometimes produce diagnostic confusion during radiographic examinations.
- These glands may sometimes occur in association with other facial anomalies.
ATRESIA
Atresia of the salivary gland excretory ducts refers to the congenital absence or narrowing of the duct system.
Atresia of developmental origin is an extremely rare condition, which may produce severe xerostomia. It can also results in the formation of retention cyst of the salivary gland. According to some investigators there can be another developmental defect in the excretory salivary duct system, which is characterized by absence of the duct oriface. This also can produce salivary retention cyst and xerostomia.
ACCESSORY DUCTS
Accessory salivary ducts are relatively common developmental malformations, which can occur in relation to any gland, though it is seen more often in association with the parotids. The accessory parotid ducts are usually found either above or below the normal stensen's duct. Accessory ducts of the salivary glands most often remain undetected since their presence do not produce any clinical effect in the mouth.
DIVERTICULI
Diverticuli refer to the small pouches or outpocketings of the ductal system of the major salivary glands. It is also predominantly found in relation to the parotids. Diverticuli may produce recurrent swellings and acute sialadenitis due to retention of saliva in those areas where the pouches are present along the course of the duct. Diverticuli are diagnosed by sialogram.
LINGUAL MANDIBULAR SALIVARY GLANDS DEPRESSION
It is a developmental concavity in the lingual cortex of mandible, usually in the third molar area, which forms around an accessory salivary gland. The condition is also referred by several other names such as Stafne's bone cyst, static bone cyst or latent bone cyst, etc.
Clinical Features
- Clinically lingual mandibular salivary gland depression is a completely asymptomatic condition.
- It is almost exclusively seen among males.
- Usually seen in the mandibular third molar areas. Occasionally the condition can also involve the lingual aspect of anterior mandible.
Radiographic Features
- Radiographically this relatively uncommon entity presents a distinct, localized, deep concavity or depression located on the lingual aspect of mandible.
- In most cases it is found in the mandibular third molar region in between the mandibular canal and the lower border of mandible.
Differential Diagnosis
Hemorrhagic bone cyst, this cyst almost always lies above the mandibular canal while the lingual mandibular salivary gland depression lies below the canal.
Sialography
Sialography reveals that the concavities in the mandible are usually occupied by accessory lateral lobe of the submandibular salivary gland.
Further Investigations
- Surgical exploration and subsequent biopsy of the contents of the lingual concavity generally reveals normal submandibular salivary gland tissue.
- Sometimes CT scan and MRI (Magnetic Resonance Imaging) techeniques can be employed to confirm the nature of tissue present within the concavity.
Treatment
No treatment is required.
DEVELOPMENTAL ANOMALIES INVOLVING ORAL HARD TISSUES
ABNORMALITIES OF TEETH
The tooth development begins at about the sixth week of the intrauterine life when few cells of the oral ectoderm undergo proliferation and eventually result in the formation of the dental lamina. The odontogenic cells (toothforming) emerge from dental lamina and the later event constitutes the beginning of tooth development. The development of tooth occurs in several stages, namely the
- The stage of initiation (bud stage).
- The stage of proliferation (cap stage).
- The stage of histodifferentiation (bell stage).
- The stage of morphodifferentiation.
- The stage of apposition.
- The stage of calcification and
- The stage of eruption.
Developmental anomalies may occur during any of these developmental stages of teeth, which are, manifested clinically in the later life once the tooth is fully formed. These anomalies of tooth can occur either due to genetic factors or due to some environmental factors, however in few instances, both of these factors could be involved together to cause some defects in the teeth.
DISTURBANCE IN SIZE OF TEETH
MICRODONTIA
Definitions
Microdontia is the condition in which one or more teeth are smaller than normal.
It is important to note that the size of both the teeth and the jaws are almost always genetically determined. However wide variations are often seen in the ratio of tooth size and jaw size. Therefore alterations in the size of the tooth are often proportionately variable to the size of the jaw.
Types of Microdontia
True Generalized Microdontia
- When all the teeth in both arches are uniformly and measurably smaller than normal the condition is known as true generalized microdontia.
- This is an extremely uncommon condition and can be seen in pituitary dwarfism.
- True generalized microdontia can also be associated with other congenital defects like Down syndrome and congenital heart disease, etc.
Relative Generalized Microdontia
- Relative generalized microdontia is the condition in which tooth of normal size may look smaller if they are placed in an abnormally large maxilla or mandible.
- In such cases larger size of the jaws give an illusion of microdontia although the teeth are not really small.
- Relative microdontia often exhibits spacing in between the teeth.
Focal Microdontia
- When one or two teeth are smaller than normal it is called focal microdontia.
- Microdontia involving one or two teeth in the dental arch is far more common than the generalized types.
- The affected teeth are often present symmetrically in the jaw and in addition to being miniature in size, these teeth often exhibit alteration in their shape as well.
- Maxillary lateral incisors and maxillary third molars are the most frequently involved teeth in focal microdontia.
- When maxillary lateral incisors are involved, the teeth often appear ‘cone’ or ‘peg’ shaped and are often designated as peg laterals.
- These peg laterals carry an autosomal dominant type of inheritance pattern.
- Maxillary and mandibular second premolars may sometimes exhibit microdontia.
- Supernumerary teeth are almost always smaller than the normal teeth and are often conical in shape.
- There are certain situations in which smaller teeth can be found in the mouth, although these conditions may not be truly developmental in nature.
Examples:
- Smaller teeth can be seen in the affected side of the jaw in facial hemiatrophy.
- In gemination or twinning one single tooth germ splits into two during development and gives rise to two separate teeth, which are always smaller than normal.
- Small, conical teeth are often seen in hereditary ectodermal dysplasia.
- Multiple miniature teeth can be found in compound odontome.
- A retained deciduous tooth within the permanent dentition may give an illusion of focal microdontia.
Clinical Significance of Microdontia
- In microdontia teeth are often spaced which may be disturbing cosmetically.
- If shapes of these teeth are also altered along with microdontia (e.g. peg laterals), it will require immediate correction.
- Crown and bridge prosthetic work may be required for esthetic rehabilitation of such teeth.
MACRODONTIA
Definition
Macrodontia is a condition in which teeth in the jaws are measurably larger than normal in size.
Types of Macrodontia
Macrodontia can be of three types, which are as follows:
- True generalized macrodontia When all the teeth in both arches are measurably larger than normal, the condition is termed as true generalized macrodontia. It can be seen in case of pituitary gigantism.
- Relative generalized macrodontia Relative generalized macrodontia is used to designate a condition in which the normal sized teeth appear somewhat larger because of the smaller jaw size. In such cases the dental arches often exhibit crowding of teeth.
- Focal or localized macrodontia Localized macrodontia is occasionally seen on the affected side of the mouth with hemifacial hyper-trophy. Macrodontia of individual tooth is a rare entity and it mostly affects the incisors. However focal macrodontia should not be confused with ‘fusion’ of teeth in which two adjacent teeth unite together to form a single large tooth.
DISTURBANCE IN NUMBER OF TEETH
ANODONTIA
Definition
Anodontia can be defined as a condition in which there is congenital absence of teeth in the oral cavity.
Types
Anodontia can be of two Types
- Complete or total anodontia Congenital absence of all teeth.
- Partial or sub-total anodontia Congenital absence of one or few teeth.
Anodontia can also be divided into the following types:
- True anodontia True anodontia occurs due to failure of development or formation of tooth in the jawbone.
- Pseudoanodontia Refers to the condition in which the teeth are actually present within the jawbone but are not clinically visible in the mouth, as they have not erupted. Examples of pseudoanodontia can be impacted teeth or submerged teeth, etc.
- False anodontia False anodontia is the condition in which the teeth are missing in the oral cavity because of their previous extraction or exfoliation.
Etiology of Anodontia
- Hereditary factor.
- Environmental factor.
- Familial factor.
- Syndrome associated.
- Radiation injury to the developing tooth germs.
TOTAL ANONDONTIA
Total anodontia is a rare condition in which there is neither any deciduous tooth nor any permanent tooth present in the oral cavity.
- It is usually seen in association with hereditary ectodermal dysplasia. This condition is usually inherited as an x-linked recessive trait and although it primarily affects males but an autosomal dominant form can occur, which affects females.
- There will be defect in the ectodermally derived structures of the body such as hair, sweat gland, teeth and salivary gland, etc. with a typical inability to regulate body temperature.
- Although complete anodontia is a common feature of hereditary ectodermal dysphasia, however in many cases the cuspids are present in this disease and the teeth are often malformed with conical crowns.
- Complete anodontia sometimes occur among children those who have received high doses of radiation to the jaws as infants for therapeutic reasons.High doses of radiation cause destruction of tooth germs resulting in complete lack of tooth formation in future, moreover even a very lower dose may cause cessation of dontogenesis.
PARTIAL ANONDONTIA
Partial anodontia is a much more common phenomenon and is characterized by congenial absence of one or few teeth. This condition is also know as hypodontia or oligodontia.
In partial anodontia when a deciduous tooth is congenitally absent it is very much likely that its permanent successor will also be missing thereby suggesting some genetic influence.30
A familial tendency for congenitally absent teeth is a well-recognized phenomenon.
Incidence Rate
Incidence rate of partial anodontia varies in different population groups but nearabout 35% of the general population will have at least one congenitally missing tooth.
Commonly Missing Teeth in Partial Anodontia
- In partial anodontia any tooth can be congenitally missing, however it is often noticed that certain teeth tend to be absent more often than others.
- The third molars (any one or all four of them) are the most frequently observed congenitally missing teeth.
- Maxillary lateral incisors and mandibular premolars are the next most common group of teeth, which are often congenitally absent.
- When deciduous teeth are involved it partial anodontia, the maxillary lateral incisors are most likely to be affected.
- It should be noted that mandibular first molars and mandibular lateral incisors are the teeth, which are least likely to be missing during anodontia.
Diseases or Clinical Conditions to be Commonly Associated with Partial Anodontia
Incontinentia pigmenti This hereditary disorder is characterized by diffuse slate-grey macules of the skin, white lesions of the oral mucosa, skeletal, ocular and neuralgic disturbances; and partial anodontia with delayed eruption of tooth.
Hyalinosis cutis mucosae This disease is characterized by pathologic accumulation of glycoprotein in the body and it often manifests with the following features:
Hoarseness of voice, vesicular skin lesions, nodular or papillary lesions of the oral mucosa, intracranial calcifications and hypodontia.
Mandibulo-Oculo-Facial dyscephaly This disease is also known as Hallermann-Steriff syndrome and is characterized by brachycephaly, frontal bossing, microstomia, TM joint disturbance, blue sclera, hypotrichosis and hypodontia with retention of deciduous teeth.
Chondroectodermal dysplasia This hereditary disorder is characterized by developmental abnormalities in both ectodermal and mesodermal tissues. Although it shares few features with hereditary ectodermal dysplasia but both are different pathologic entities.
Chondroectodermal dysplasia clinically manifest with the features like—defective nails and hair, normal sweat glands, congenital absence of numerous teeth, fusion of the upper lip to the anterior maxillary alveolar ridge, short limbs with polydactyly and congenital heart defects etc.
Book's syndrome This syndrome is commonly associated with localized hypodontia and its other features include—premature whitening of hairs and hyperhydrosis of the palms and soles.
Rieger's syndrome It is an autosomal dominant hereditary disorder and it shows oligodontia or hypodontia with serious ophthalmic defects.
SUPERNUMERARY TEETH
Definition
Presence of any extra tooth in the dental arch in addition to the normal series of teeth is called supernumerary tooth.31
Mode of Formation
- A supernumerary tooth may develop either from an accessory tooth bud in the dental lamina.
- It may develop due to spitting of a regular normal tooth bud during the initial phase of odontogenesis.
- The supernumerary tooth can occur in both males as well as in females.
- A supernumerary tooth may resemble the corresponding tooth (i.e. where they are located) but in many cases it may have a conical shape. Therefore, morphologically sometimes these teeth may look like molars, premolar or like incisors, etc. depending upon their location or sometimes they may have an altogether different morphologic appearance. However in most of the cases these extra teeth are much more smaller in size (miniature form) than their normal counterparts.
Locations
- Supernumerary teeth can occur in any location but they often have a predilection for certain sites.
- These are far more common in maxilla (90%) as compared to mandible.
Types
Supernumerary tooth occurring at certain sites may be known by certain special terms and these are as follows:
Mesiodens Mesiodens are the most common types of supernumerary teeth, which are located between the two upper central incisors.
Distomolars Distomolars are supernumerary molars, which are usually located on the distal aspect of the regular molar teeth in the dental arch.
Paramolars These are also extra molar teeth, which are usually located either in the buccal or in the lingual aspect of the normal molars.
Extra lateral incisors Although rare, extra lateral incisor teeth can be present and they are more common in the maxillary arch.
In mandible the most common supernumerary teeth are the extra premolars, although fourth molars or additional incisors are also occasionally found.
Although rare, supernumerary teeth can occur in the deciduous dentition and whenever they occur, the most common one is the maxillary lateral incisor.
Most of the supernumerary teeth exhibit conical crowns; they may be either single or multiple in numbers and are either erupted or impacted.
Clinical Features
- Supernumerary teeth may sometimes produce crowding or malocclusion and they cause cosmetic problems.
- In many cases these extra teeth may be either directly or indirectly responsible for increased caries incidence and periodontal problems.
- Multiple supernumerary teeth (most of them are impacted), can occur in association with conditions like cleidocranial dysplaisa or gardener'syndrome etc.
- Dentigerous cysts may sometimes develop from an impacted supernumerary tooth.
Treatment
- Supernumerary teeth are mostly non functional and they should be extracted.
- Impacted supernumerary teeth should also be removed surgically since they can interfere with normal tooth alignment or can develop some pathology.
DISTURBANCES IN ERUPTION
The eruption time for both deciduous and permanent teeth often vary among different persons. Therefore it is sometimes difficult to assess the exact eruption time for a particular tooth in any given individual. However, when the eruption time or sequence is obviously much beyond the normal range, then we can consider that an eruption abnormally exists.32
Types of Rruption Abnormalities
- Premature eruption
- Delayed eruption
- Impacted tooth
- Embeded tooth
- Eruption sequestrum.
PREMATURE ERUPTION
Definition
Premature eruption can be defined as a situation when a tooth erupts into the oral cavity much before its normal time of eruption.
Types
- Natal teeth These are erupted deciduous teeth present at birth.
- Neonatal teeth These are deciduous teeth, which erupt during the first 30 days of life.
Etiology
The exact etiology of premature eruption is not known; however a familial pattern is sometimes noticed.
Commonly Involved Teeth
- Premature eruption usually involves only one or two teeth, most commonly the deciduous mandibular central incisors.
- Natal or neonatal teeth are not supernumerary teeth, in fact they are part of the normal component of deciduous dentition and therefore these teeth should be preserved in the mouth if possible.
- Premature eruption of permanent teeth may occur as a result of loss of preceding deciduous teeth at a much earlier time. It is often seen that when a single deciduous tooth exfoliates prematurely, its permanent counterpart erupts much before its normal time of eruption.
- However in hyperthyroidism the entire permanent dentition may erupt prematurely.
DELAYED ERUPTION
Definition
Delayed eruption refers to the first appearance of the deciduous tooth in the oral cavity at a much later time than what is normally expected.
This is a relatively uncommon phenomenon and can involve both deciduous as well as the permanent dentition.
Factors Causing Delayed Eruption of Tooth
Systemic Factors
- Rickets.
- Cleidocranial dysplasia.
- Cretinism
Local Factors
- Gingival fibromatosis.
- Cleft lip and cleft palate
- Retained deciduous tooth.
Idiopathic
In many cases however the exact cause for the delayed eruption is not clearly known. Delayed eruption of permanent teeth may occur due to the same local or systematic factors, which are responsible for the delayed eruption of deciduous teeth.
IMPACTED TEETH
Definition
Impacted teeth are those, which fail to erupt in the oral cavity due to crowding of the dental arch 33or absence of a convenient path of eruption or due to some physical barriers.
Factors Causing Impaction of Tooth
Micrognathia A smaller jaw cannot afford to accommodate all the teeth supposed to be present in the arch, hence few of them may become impacted.
Malocclusion Abnormal orientation of some teeth, which have erupted at an earlier age may sometime block the normal pathway for the eruption of few other teeth which are due to erupt later.
Retained deciduous tooth An abnormally retained deciduous tooth may resist the eruption of its permanent counterpart and the later may sometimes become impacted.
Supernumerary tooth A Supernumerary tooth may sometimes obstruct the pathway for eruption of other teeth resulting in their impaction. On the other hand, in many instances a supernumerary tooth itself may remain impacted due to lack of space for eruption.
Odontogenic cysts (e.g. keratocyst) It may act as a physical barrier and result in the impaction of tooth in the region.
Odontogenic tumors (e.g. odontome) It also may results in impaction of a tooth by acting as physical barrier in the path of eruption.
Cleft palate In many cases, teeth may be impacted in the area of cleft palate.
Non-odontogenic tumors or cysts These lesions may sometimes cause impaction of tooth as they obstruct the path of eruption of a tooth.
Cleidocranial dyplaisa This disease entity is often associated with multiple impactions.
Gardner's syndrome It is also associated with multiple impacted teeth.
Amelogenesis Imperfecta Impacted teeth are also seen in various forms of amelogenesis imperfecta.
Syndrome associated enamel defects Impacted teeth can also be seen in case of syndrome associated enamel defects such as amelo-onycho-hypohydrotic syndrome and trichodento-osseous syndrome, etc.
Common Teeth which may be Impacted Often
- Although virtually any tooth can be impacted, the commonest impacted teeth are the mandibular and maxillary third molars.
- The next common teeth are the mandibular second premolars and maxillary canines.
- The supernumerary teeth can be impacted in many cases.
Classification of Impaction
Impactions are commonly classified in the following manner:
Mesioangular Impaction This is the common type and in this case the impacted tooth is mesially inclined.
Distoangular Impaction In this type the impacted tooth is distally inclined.
Horizontal Impaction Horizontally impacted teeth lies parallel to the long axis of the jawbone.
Vertical Impaction In this case the impacted tooth stands vertically but it occlusal plane is far blow to the occlusal plane of other erupted teeth.
Completely impacted tooth When an impacted tooth is totally surrounded by bone it is called completely impacted tooth.
A completely impacted tooth does not communicate with the oral cavity and is therefore not susceptible to caries or infection.
Embeded tooth When an individual tooth fails to erupt for no apparent cause it is called an embeded tooth.
Partially impacted tooth When an impacted tooth is partly surrounded by bone and partly by soft tissue, it is considered as a partially impacted tooth.
Partially impacted teeth often communicate with the oral cavity via an inconspicuous perio-dontal pocket and therefore make the tooth vulnerable to caries or infections.34
Radiography of Impacted Teeth
Radiographs are very much essential for determining the various aspects of an impacted tooth:
- Radiograph helps in determining the types of impaction (mesioangular or distoangular or vertical types etc.)
- It also helps to determine the position of the root apex of the impacted tooth in relation to the mandibular canal in case of lower teeth.
- It can determined the curvature of the root of the impacted tooth.
- Presence of resorptions (either root or crown) of the impacted tooth and dental caries, etc. may be detected by radiographs.
- Radiographs can help to detect any pathology, e.g. abscess, tumor or cyst, etc. which are associated with an impacted tooth.
Types of X-rays Used in Impactions
- Intraoral periapical radiographs are the most commonly used X-rays to evaluate any impaction. However other X-rays can also be useful for this purpose which include panoramic radiograph, right and left oblique lateral radiograph, standard occlusal radiograph and paranasal sinus view radiographs, etc.
Complications of Impactions
Impacted teeth may sometimes remain innocent for the entire life but in many cases they can produce some complications, which are as follows:
- Infection with associated pain and swelling.
- Trismus and extraoral sinus formation.
- Malocclusion.
- Root resorption of the adjacent erupted teeth.
- Predisposition to dentigerous cyst development.
- External resorption of the impacted tooth.
- Sometimes, impacted tooth can be found within the maxillary antrum.
- In many cases root of the impacted tooth may be present at a close proximity to the mandibular canal and in such cases possibility of damage to the neurovascular bundle is very high at the time of removal of such teeth.
- Presence of impacted tooth may weaken the jawbone in some cases and there is an increased possibility of fracture of these bone when subjected to trauma.
- Impacted teeth may predispose to the development of osteomyelitis, cellulites and space infections etc.
Treatment
Treatment modalities vary depending upon the individual impacted tooth and the specific circumstances.
- Most impacted molars are surgically extracted. However special efforts are made to save the impacted maxillary canines since these are cornerstones of the upper dental arch.
- If the impaction is caused by any physical factor such as a cyst, tumor or any supernumerary teeth, the treatment procedure must include elimination or removal of those lesions.
DISTRUBANCES IN THE SHAPE OF TEETH GEMINATION (TWINNING)
Definition
Gemination is a developmental anomaly, which refers to the partial development of two teeth from a single tooth bud following incomplete division.
- The term twinning refers to the complete and equal division of a single tooth germ that results in the formation of one normal and one supernumerary tooth.
- Gemination affects both deciduous as well as the permanent dentition.
- There is no sex predilection.
- Geminated tooth often shows doubling of both the crown as well as the root.
- Gemination mostly affects the deciduous mandibular incisors and permanent maxillary incisors.
- Clinically the geminated tooth reveals either an extremely widened crown or their can actually be an indentation or groove delineating the two crown forms.
Pathogenesis
Gemination is the result of either schizodontism-the splitting of a tooth germ during development or it can result from synodontism, the fusion of a normal tooth bud with one from a developing supernumerary tooth.
Gemination often clinically resembles another developmental anomaly called ‘fusion’. Gemination can be distinguished from fusion by the fact that full complement of teeth is present in case of gemination (one extra tooth is present in case of twinning) where as in case of fusion a regular tooth is always missing from the dental arch.
Treatment
Since gemination produces some cosmetic disturbance, construction of esthetic crown or bridge may be necessary for cosmetic rehabilitation.
FUSION
Definition
Fusion can be defined as the union of two adjacent normal tooth germs at the level of dentin during development.
- Fusion results in one anomalous large crown in place two normal teeth and is having a single enlarged root or two roots.
- One of the most important criteria for fusion is that the fused tooth must exhibit confluent dentin.
- In case of fusion a hereditary pattern is often encountered.
- Both deciduous as well as permanent teeth can be affected in case of fusion, although it is more common in deciduous teeth.
- Fusion can occur between two normal teeth or between one normal and one supernumerary tooth.
- In both dentitions, the incisor teeth are more frequently affected.
- There is no sex prediliction in case of fusion.
- Fusion can be complete or incomplete and its extent will depend on the stage of odontogenesis at which the fusion took place.
Complete Fusion
If fusion begins before the calcification of the tooth has occurred, then the fusion will be complete and the fused tooth crown will incorporate all components of both the participating teeth including their enamel, dentin, cementum and the pulp.
Incomplete Fusion
If fusion begins in the later stages of tooth development, then the fused tooth may exhibit separate crowns and the fusion process may be limited to the roots only, with pulp canals either fused or separate. This condition is called incomplete fusion.
- Radiographs can be immensely helpful in determining the complete or incomplete fusion.
- Fusion can be differentiated from gemination by counting the number of teeth in the arch, since in case of fusion there will be one tooth less in the dental arch.
Clinical Complications
Fusion Often Creates the Following Problems
- There can be spacing or diastema formation between the teeth.
- There can be crowding of teeth in the arch, when fusion occurs between one normal and one supernumerary tooth.
- Esthetic problems.
- Periodontal complication.
Treatment
Depending upon the extent of clinical problem, fabrication of cosmetic crowns or bridges may be necessary for esthetic recovery in case of fusion.
CONCRESCENCE
Definition
Union of the roots of two or more adjoining teeth due to deposition of cementum is known as concrescence.
- This is a type of fusion, which is limited only to the roots of the teeth and it occurs after the root formation of the involved teeth are completed.
Etiology
- Traumatic injury.
- Crowding of teeth.
- Hypercementosis associated with chronic inflammation.
Pathogenesis
The condition is thought to occur as a result of traumatic injury to the jaw, which causes loss of interdental bone and brings the roots of the neighboring teeth in close proximity to one another. Finally fusion occurs between the roots of two or more separate teeth due to deposition of cementum.
Important Features
- Concrescence represents an acquired defect and it can occur in both erupted or unerupted teeth.
- There is no sex predilection.
- In concrescence beside cementum, union or fusion does not occur between the enamel, dentin or the pulp of the involved teeth.
- The union mostly occurs between two teeth, however there may be unions between more than two teeth in exceptional cases.
- Permanent maxillary molars are usually affected by this anomaly.
- Concrescence can occur between a normal molar and a supernumerary molar, e.g. paramolar or distomolar, etc.
- Concrescence rarely involves the deciduous dentition.
- The condition is frequently seen in those areas of the dental arch where the roots of the neighboring teeth lie close to one another (e.g. between maxillary second and third molars).
Clinical Significance
- The clinical significance of concrescence relate primarily to its radiographic diagnosis before attempting tooth extraction. Since in unrecognized cases attempted extraction of the tooth may cause trauma or are removal of two teeth instead of one.
DILACERATION
Definition
Dilaceration refers to an angulation or a sharp bend or a curve anywhere along the root portion of a tooth.
Pathogenesis
The condition probably occurs subsequent to trauma or any other defect of development, which alters the angulation of the tooth germ during root formation.
- It is generally believed that trauma to a partially calcified tooth germ may cause displacement of the hard calcified crown portion of the tooth and later on the unclassified root portion develops by forming an angle.
- Some investigators believe that trauma is not always an essential factor for the development of dilacerations and according to them the anomaly occurs as a result of continued root formation during a curved or tortuous path of eruption.
- In some cases the cause of the defect is idiopathic.
Clinical Features
- Dilaceration may involve any tooth belonging to either the deciduous as well as the permanent dentition.
- There is no sex predilection.
- Sometimes dilaceration at the coronal portion of the teeth is observed.
Dilaceration in a tooth can easily be detected by radiographs and care should be taken during extraction of such teeth. Since these teeth are more prone to fracture.
TAURODONTISM
Definition
Taurodontism or ‘bull-like’ tooth is a peculiar developmental condition in which the crown portion of the tooth is enlarged at the expanse of its roots.37
Pathogenesis
The condition probably occurs due to failure of the Hertwig's root sheath to invaginate at the proper horizontal level.
Features
- The affected tooth in taurodontism exhibits elongated pulp chamber with rudimentary root formation.
- The teeth are usually rectangular in shape with minimum constriction at the cervical area, the furcation area of the teeth are more apically placed than normal.
- The teeth often have a greater apico-occlusal height and the furcation of the roots usually placed beyond the cervical area.
- Clinically the teeth exhibit certain morphologic changes and this defect can involve both sexes equally.
- Taurodontism commonly affects the multirooted permanent molar teeth and sometimes the premolar teeth. This condition is rarely seen in primary dentition.
- This dental anomaly may be sometimes associated with some craniofacial deformities, e.g. Down syndrome, Klinefelter syndrome, amelogenesis imperfecta and Poly-X syndrome, etc.
- Patients with hypodontia may have taurodontism in about 30% cases.
- Anthropologic studies indicate that taurodontism was relatively common among Neanderthal men.
Treatment
No treatment is required for taurodontism, however this anomaly can pose some difficulty during root canal treatments.
DENS-IN-DENTE (DENS INVAGINATUS)
Definition
Dens-in-dente represents a defect in the morphologic development of tooth in which a focal area on the tooth surface is folded or invaginated pulpally to a variable extent
- The defect in generally localized to a single tooth and interestingly maxillary lateral incisors are more often affected than any other tooth in the dental arch.
- Bilateral involvement (of the same tooth) is often seen and sometimes the defect can involve multiple teeth including the supernumeraries.
Types
Dens-in-dente is often broadly divided into two types—coronal type and radicular type.
Coronal type Coronal type of dens-in-dente occurs when the invagination or folding occurs on the crown portion of the tooth.
Radicular type In case of dens-in-dente if the invagination occurs in the root portion of the tooth it is called the radicular type and the condition presumably occurs due to folding of the Hertwig's sheath during the development of root.
Clinical Forms of Dens-in-dente
Depending upon the extent of the invagination towards the pulp, the dens-in-dente presents several clinical forms and these are mostly determined by radiographs.
Mild form This form of dens-in-dente is characterized by the presence of a deeply invaginated or accentuated lingual pit area. Such external pits can be clinically inconspicuous but are clearly visible with the periapical radiographs.
Intermediate form Intermediate form of dens-in-dente radiographically reveals a small, pear shaped invagination of the enamel and dentine into the pulp chamber, this produces a typical appearance of “tooth-within-a tooth”.
Extreme form In this form of dens-in-dente the invagination extends beyond the pulp chamber in the root of the affected tooth. This condition is sometimes known as “dialated odontomes”.
Clinical Significance of Dens-in-dente
Since the base of the pit or the deep invagination in dens-in-dente is composed of a thin and often-defective 38layer of enamel and dentine, these are extremely vulnerable to caries soon after the tooth erupts into the oral cavity.
For this reason most of the teeth having this defect may develop pulpitis, pulp necrosis, periapical cysts or abscesses, etc.
Treatment
Early detection of the condition and restoration of the defect. In case of pulp involvement with or without apical pathology, endodontic treatment should be attempted. However in more severe form of the defect, extraction should be done.
DENS-EVAGINATUS
Definition
Dens-evaginatus is a developmental anomaly of tooth in which a focal area of the crown projects outwards and gives rise to a “globe shaped” or “nipple shaped” protuberance on the occlusal surface, which appears as an extra cusp.
Pathogenesis
Dens-evaginatus probably develops as a results of excessive localized elongation and proliferation of the inner enamel epithelium as well as the odontogenic mesenchyme into the dental organ. The condition usually occurs during the early stage of tooth development.
Clinical Features
- Dens-evaginatus primarily affects the premolars, and in these affected teeth the globe shaped extra cusp is often centrally located on the occlusal surface between the buccal and lingual cusps.
- The condition can also affect the molars, canines or even the incisors. In such cases the defect may occur either unilaterally or bilaterally.
- Dens-evaginatus is commonly seen among Chinese, Japanese, Filipino, American-Indians and occasionally Caucasians.
- Clinically this defect may sometimes interfere with tooth eruption and in such cases there may be incomplete eruption of tooth or displacement of tooth with occlusal disharmony.
- Since the extra cusp contains a vital pulphorn, its attrition or fracture may result in pulp exposure, leading to pain, pulpitis and the other associated complications.
- Similar complications may also arise when reduction of the extra cusp is attempted intentionally by the dentist.
Treatment
The condition usually does not require any treatment as long as it is asymtomatic. In case of occusal disharmony, minor reduction should be attempted. However in case of exposure or fracture of the extra cup, endodontic treatment of the tooth should be done.
TALON CUSP
Definition
Talon cusp is an anomalous projection from the lingual aspect of the maxillary and mandibular permanent incisors.
Clinical Features
- The name talon cusp has evolved since this anomalous structure often resembles an “eagle's talon”.
- This abnormal cusp arises from the cingulum area of the tooth, which extends to the incisal edge as a prominent T-shaped projection.
- It is usually an asymptomatic condition however, in some cause it may problems in terms of esthetics, susceptibility to caries and occlusal accommodations, etc.
- The projected structure in talon cusp usually consists of normal appearing enamel and dentin; although in few cases there can be presence of vital pulp tissue in it.
- Occasionally lingual pits develop on either side of the talon cusp, where it joins the lingual surface of the tooth.
- This anomaly is rare among general population and it is often associated with patients suffering from Rubinstein-Taybi syndrome.
Treatment
- Whenever the lingual pits are present restorative treatments should be done to prevent caries.
- When talon cusp interferes with normal occlusion, preventive care should be taken by performing endodontic and restorative treatment.
ENAMEL PEARL
Enamel pearls are white, dome shaped calcified projections of enamel, usually located at the furcation areas of the molar teeth.
Maxillary molars are more frequently affected than any other teeth.
Enamel pearls are radiographically seen as 1 to 3 mm round radiopaque areas at the furcation region of tooth.
Histologically these are compose of normal appearing enamel sometimes with a central core of dentin.
It is believed that the epithelial component of root sheath of Hertwig may sometimes retain its ameloblastic potential and therefore may synthesize enamel in some focal areas in place of cementum. This give rise to the formation of enamel pearl.
DISTRUBANCE IN THE STRUCTURE OF TEETH
DISTRUBANCE IN THE STRUCTURE OF ENAMEL
Enamel is normally formed by the specialized odontogenic epithelial cells called ameloblasts and the entire process of formation of enamel takes place in three distinct stages, which are as follows:
Stage I: (Secretary stage) | Enamel matrix formation |
Stage II: | Initial mineralization |
Stage III: | Enamel maturation |
Enamel matrix formation In the first stage or Secretary stage the ameloblast cells cause synthesis and secretion of special proteins namely the amelogenins and enamelins. These two proteins constitute the basic structural elements of the enamel matrix.
Initial mineralization Initial mineralization starts immediately after the secretion of enamel matrix proteins and after that enamel microcrystals start to abut the plasma membrane of the ameloblast cells.
Maturation The stage of maturation is characterized by simultaneous dual activity of withdrawal of protein and water from enamel with concomitant huge increase in its mineral content. All these three stages are completed before the eruption of the tooth in the oral cavity.
During the process of enamel formation, the ameloblast cells are susceptible to various external factors, which can disturb the process and the effect of which is reflected on the surface enamel after the eruption of tooth.
Defect in the enamel due to disturbance during its formative process can be either qualitative or it can be quantitative.
- Quantitatively defective enamel having normal thickness is known a enamel hypoplasia.
- Qualitatively defective enamel having normal thickness is called enamel hypocalcification.
Therefore, depending upon the stages of formation of enamel the defects, which may occur in it under the influence of the external factors, are as follows
DEFECTIVE AMELOGENESIS
- Matrix formation—Enamel hypoplasia
- Initial mineralization—Enamel hypocalcification
- Maturation—Enamel hypomineralization
ACQUIRED DISTURBANCES
FOCAL ENAMEL HYPOPLASIA
When local infection or trauma causes damage to the ameloblast cells during odontogenesis, it may result in defects in enamel formation in isolated permanent tooth and this phenomena is often known as focal enamel hypoplasia.40
| Aetiology of Developmental (structural) Abnormalities of Enamel |
Acquired causes: | Hereditary (Genetic) causes: | |||
|---|---|---|---|---|
a. | Local factors: | a. | Condition in which only the teeth are affected: | |
Infections Trauma Radiotherapy Idiopathic (enamel opacities) | Amelogenesis imperfecta | |||
b. | Environmental/Systemic factors: | b. | Teeth affected along with general defect: | |
i. Prenatal: | - Prenatal infection, e.g. rubella, syphilis. - Internal disease - Excess fluoride ions. | Syndrome associated enamel defects. | ||
ii. Neonatal: | - Hemolytic disease of the newborn. - Birth injury - Premature delivery - Prolonged labor - Low birth weight. | |||
ii. Post natal | - Severe childhood infections (Viral exanthemata). - Prolonged fever due to infectious disease in childhood. - Chronic childhood disease - (Congenital heart disease, Endocrine disease, Gastrointestinal disease).
| |||
- This is probably the most common form of enamel hypoplasia among all varieties and it often occurs either due to periapical spread of infection from a carious deciduous tooth or trauma to the deciduous tooth.
- In such cases the trauma or the infection in the existing deciduous tooth may cause damage to the ameloblast cells forming the crown of the underlying permanent successor.
- The tooth affected in this process is commonly known as the ‘Turner's tooth’.
- Depending on the severity of the injury, the crown of the Turner's tooth may have an area of enamel hypoplasia that is relatively smooth with some pitted areas.
- However in very severe cases, the crown of the Turner's tooth is grossly deformed and exhibits a yellowish or brownish discoloration of the surface.
IDIOPATHIC ENAMEL OPACITIES
- The condition is characterized by white opaque spots on the smooth surface enamel, which occur due to some unknown cause.
- Some of these spots may eventually turn brown after the tooth is erupted in the mouth.
- Enamel opacities may affect deciduous as well as permanent dentition and maxillary central incisor is the most frequently involved tooth.
- Histologically these opaque spots represent the area of hypomineralization.
GENERALIZED ENAMEL HYPOPLASIA
A short-term systemic or environmental disturbance in the functioning of ameloblasts at a specific period of time during odontogenesis often manifests clinically as a horizontal line of small pits or grooves on the enamel surfaces.
This line on the tooth surface indicates the zone of enamel hypoplasia and it corresponds to the time of development and the duration of the insult.
If the duration of the systemic or environmental insult is brief, the line of hypoplasia on the enamel surface will be narrow, whereas a prolonged insult may produce a wider zone of hypoplasia and also affect more teeth as well.
It has been observed from different clinical studies that the generalized enamel hypolasia due to systemic or environmental disturbances usually involves those teeth, which are normally formed in children during their first year of life. That is why the teeth like the permanent incisors, cuspids and the first molars are often affected by generalized enamel hypoplasia.
Whereas the teeth like premolars, second molars and third molars are seldom affected by this defect since formation of the teeth begins usually 3 years after birth or even later.
EFFECT OF INDIVIDUAL SYSTEMIC CONDITIONS ON ENAMEL HYPOPLASIA
NUTRITIONAL DEFICIENCY
Since ameloblasts are amongst the most sensitive cells in the body in terms of metabolic requirements, any serious nutritional deficiency occurring during odontogenesis may result in generalized enamel hypoplasia of teeth.
- Deficiency of Vitamin A, C, and D often causes injury to the ameloblast cells and results in enamel hypoplasia.
- Hypoplasia of enamel due to nutritional deficiency commonly affects the central and lateral incisors, cuspids and the first molars.
- The teeth exhibit variable amount of pitting on the enamel surface.
CONGENITAL SYPHILIS
Enamel hypoplasia resulting from congenital syphilis is a well known phenomenon.
- The disease is contracted by the child in utero from a mother who has active infection with Treponema pallidum.
- In syphilis the infection is diffuse in nature and it can involve virtually any tissue of the body. However certain body tissues like the bone, nerves and the teeth are more susceptible to this infection as compared to other tissues of the body.
- The disease produce characteristic hypoplastic change in the enamel of permanent incisors and first molars due to infection to the developing tooth germ by Treponemal spirochetes.
- The organism causes inflammation of the tooth germ during the morphodifferentiation stage resulting in hyperplasia in the epithelium of the enamel organ.
- Because of the inflammation of the tooth germ and subsequent hyperplastic change in the enamel organ, enamel hypoplasia results often in association with some specific morphologic changes in the affected tooth.
- In congenital syphilis the affected permanent incisors exhibit tapering of the mesial and distal surfaces towards the incisal edge rather than torward the cervical margin and this gives a typical ‘screwdriver’ appearance of these teeth. Moreover, these teeth also have a central notch at their incisal edge and hence are called ‘Hutchinson's incisors’. These changes are 42more pronounced in maxillary central incisors. The lateral incisors in congenital syphilis are usually “peg-shaped” and are called “peg-laterals”.
- The disease also produces some classic changes is molar teeth, usually first molars, which are characterized by a crumpled and discolored occlusal surface and occlusal two third area of the crown, being covered by a small globular mass of enamel. Such teeth are popularly known as ‘Moon's molars’ or ‘Mulberry molars’.
- It is important to note that not all the patients suffering from congenital syphilis will develop the hypoplastic enamel defects in their teeth as discussed earlier.
- Moreover few people may exhibit similar dental changes, who do not suffer from congenital syphilis.
HYPOCALCEMIA
Enamel hypoplasia may result from hypocalcemia secondary to Vitamin-D deficiency and the defect is usually pitting type.
EXANTHEMATOUS DISEASE
- Severe exanthematous childhood infections often cause generalized enamel hypoplasia and it probably happens due to prolonged high fever associated with the infection, which may result in injury to the ameloblast cells.
- In such cases the enamel hypoplasia will usually occur in those portions of the teeth, which are undergoing development at the time of infection.
- Similar kinds of enamel hypoplasia can also occur in rickets and in congenital hypoparathyroidism.
BIRTH INJURIES AND LOW BIRTH WEIGHT
- Enamel hypoplasia is a common developmental anomaly in case of birth injuries and it might happen due to a transient cessation of ameloblastic activity at the time of injury during labor.
- Children of low birth weight often exhibit enamel hypoplasia and it probably results from oxygen deprivation and mineral depletion to the ameloblast cells during perinatal management.
- Both deciduous as well as the permanent teeth will develop hypoplastic enamel in these conditions.
FLUORIDES
If fluoride levels in the drinking water exceeds one PPM (Parts Per Million) it can cause mottling of enamel. Mottling is a type of enamel hypoplasia, which occurs as a result of damage to the ameloblast cells due to fluoride toxicity when the ion is absorbed in the body at a higher concentration. Besides causing damage to the enamel forming cells the fluorides also cause disturbance in the calcification process of enamel and mottling actually results from this dual effect of fluoride toxicity.
- Mottling is a generalized disturbance affecting all the teeth exposed to excess fluoride during odentogenesis.
- Both deciduous as well as the permanent dentition are affected.
- The mottled teeth often have a chalky and opaque surface with areas of flecking or pitting.
- The damage can be extensive in some teeth showing fracturing of enamel with an associated brown or black pigmentation.
HEREDITARY DISTURBANCE OF ENAMEL FORMATION
AMELOGENESIS IMPERFECTA
Definition
Amelogenesis imperfecta is a heterogenous group of hereditary disorders of enamel formation, affecting both deciduous and the permanent dentition.
The disease involves only the ectodermal component of the tooth (i.e. enamel) while the mesodermal structures of tooth, e.g. dentin, cementum and pulp, etc. always remain normal.43
Types
Normally the process of enamel formation progresses through three stages:
- Stage of enamel matrix formation.
- Stage of early mineralization.
- Stage of enamel maturation.
Amelogenesis imperfecta may set in during any stage of enamel formation. Three basic types of amelogenesis imperfecta have been identified, which correlate with defects in these three developmental stages of enamel.
- Hypoplastic type of amelogenesis imperfecta
- Hypocalcification type of amelogenesis imperfecta.
- Hypomaturation type of amelogenesis imperfecta.
Hypoplastic Type
In this type the enamel thickness is usually far below normal since the disease affects the stage of matrix formation. The teeth exhibit either complete absence of enamel from the crown surface or there may be a very thin layer of enamel on some focal areas.
Hypocalcification Type
Hypocalcification type of amelogenesis imperfecta represents that stage of the disease, which has occurred due to disturbance in the process of early mineralization of the enamel.
In this stage, the enamel is of normal thickness but is soft and can be easily removed with a blunt instrument.
Hypomaturation Type
This type occurs due to interruption in the process of maturation of enamel. Here the enamel is of normal thickness but it does not have the normal hardness and translucency. The enamel can be pierced with an explorer tip with firm presssure. Teeth often show chipping of enamel away from the normal dentin surface.
Clinical Features
- Amelogenesis imperfecta affects both deciduous and the permanent teeth.
- Sex predilection varies according to the mode of inheritance.
- The color of the teeth are mostly chalky white but sometimes it can be yellow or even dark brown.
- The contact points in the proximal surfaces are mostly open while the occlusal surfaces and the incisal edges are severely abraded.
- Sometimes the tooth is completely devoid of enamel and the patient shows severe abrasion of the dentin.
- The enamel may have a cheesy consistency which are easily removable from the tooth surface.
- On rare occasions, the enamel may look almost normal except the presence of few grooves and wrinkles on its surface.
- Amelogenesis imperfecta does not increase the susceptibility of teeth to dental caries.
- In the mildest form of hypomaturation of type of amelogenesis imperfecta, the enamel is of near normal hardness and has some white opaque flecks at the incisal areas of the teeth. These type of teeth are known as “Snow-capped teeth”.
Radiographic Appearance
In amelogenesis imperfecta, the thickness and radiodensity of enamel varies greatly. If the enamel is present at all, it can be found mostly on the tip of the cusps and on the interproximal areas.
- In hypoplastic type, the radiodensity of the enamel is usually greater than the adjacent dentin.
- The radiodensity of enamel in hypomaturation type is almost equal to that of the normal dentin.
Histopathology
Histologically the enamel in hypoplastic type of amelogenesis imperfecta exhibits lack of 44differentiation of the ameloblast cells with little or no matrix formation.
The enamel in hypocalcification type shows defective matrix structure and abnormal or subnormal mineral deposition.
The hypomaturation type reveals alteration in the enamel rod and rod-sheath structures.
Treatment
There is no definitive treatment for amelogenesis imperfecta, composite veneering can be done to improve esthetic of the teeth.
SYNDROME ASSOCIATED ENAMEL DEFECTS
A large number of syndromes as well as other pathological conditions have been identified, which are associated with some form of dental anomales in general and enamel defects in particular. In the following section few such syndromes or conditions will be discussed.
Epidermolysis bullosa It is bullous disease of the skin and mucous membrane. Dental defects associated with this disease include—enamel hypoplasia with random pitting.
Morquio's syndrome (Type-IV-Mucopolysaccharoidoses) Dental defects which occur in association with this syndrome include
- Enamel hypoplasia with pointed peak-like cusp tips.
- Grey colored teeth having vertically oriented pits on the surface.
Sanfilippo's syndrome (Mucopolysaccharoidoses type-III) This syndrome presents features like-loss of enamel from the dentinal surfaces, defective formation of dentin, with obliteration of pulp chamber.
Oculodento-osseous dysplasia Dental defects in this syndrome include—thick mandibular bone.
- Multifocal enamel hypoplasia on the tooth surface with pitting.
- Moth-eaten radiographic appearance of the teeth due to such hypoplastic changes.
Amelo-onycho-hypohidrotic syndrome This syndrome often shows severe hypoplastic-hypocalcified enamel.
Tricho-dento-osseous syndrome Hypoplastic-Hypocalcified enamel with pitting of the surface.
Rieger syndrome Enamel hypoplasia with-abnormally shaped teeth.
DISTURBANCES IN STRUCTURE OF DENTINE
Dentin is the first formed dental hard tissue and it is produced by the specialized odontogenic mesenchymal cells called the odontoblasts. These dentin forming cells or odontoblasts are derived from the mesenchymal cells of the dental papilla under the influence of the internal enamel epithelium. In the initial stage of dentin formation a collagenous matrix is formed, which is embedded in a ground substance rich in glycosaminoglycans (gag). When sufficient thickness the dentin matrix is achieved the odontoblast cells migrate through it centripetally and their processes remain in the matrix, which begin to mineralize later. Mineralization of dentin is initiated by the formation of small crystallines, which subsequently grow and fuse together to form discrete calcific globules called calcospherites.
In most of the cases, the factors which are causing interference in the process of dentinogenesis are genetic in organic. There are some environmental factors, which can also cause disturbance in the normal dentine formation.45
Classification of Developmental Abnormalities of Dentine
Local Causes
Trauma-Turner's teeth.
General Causes
- Dentinogenesis imperfecta:Type-I—Dentinogenesis imperfecta associated with osteogenesis imperfecta.Type-II—Dentinogenesis imperfecta not associated with osteogenesis imperfecta (only teeth are affected).Type-III—Dentinogenesis imperfecta of Brandy wine type.
- Dentin dysplasia:Type-I—Radicular dentin dysplasia (rootless teeth)Type-II—Coronal dentin dysplasia.
- Environmental/systemic:Vitamin-D —dependent rickets.Vitamin-D—resistant rickets (hypophosphataemia).Hypophosphatasia.Juvenile hypoparathyroidism.Other mineral deficiencies.Drugs, e.g. chemotherapeutic agents.
DENTINOGENESIS IMPERFECTA
Definition
Dentinogenesis imperfecta is an inherited disorder of dentin formation, which affects the deciduous as well as the permanent dentition and it usually exhibits an autosomal dominant mode of transmission. The disorder has been classified into three types:
Type-I: Dentinogenesis imperfecta, which occurs in patients afflicted with osteogenesis imperfecta (OI).
- This type is usually inherited as an autosomal dominant trait.
- It involves the deciduous teeth more often than the permanent teeth.
- Teeth will usually have an opalescent color (as seen in type II as well).
- Patients will exhibit features of osteogenesis imperfecta (since both conditions occur together), which include bluish selera of the eyes and several bony defects.
- It is important to note that not all cases of osteogenesis imperfecta will be associated with dentinogenesis imperfecta.
- Moreover, there is no correlation between dentinogenesis imperfecta and the severity of the osseous defects present in osteogenesis imperfecta.
Type-II: Dentinogenesis imperfecta, which is not associated with osteogenesis imperfecta.
- This type of dentinogenesis imperfecta is often known as “hereditary opalescent dentine” and this variant is more commonly encountered than the other two types of dentinogenesis imperfecta.
- It is the most common type among all the three types of the disease, having incidence rate about 1 in 8000 people.
- The condition is inherited as an autosomal dominant trait.
- Involves deciduous and permanent teeth with equal frequency.
Type-III: Dentinogenesis imperfecta type III or the “Brandywine type” is a rare condition and is inherited as an autosomal dominant trait.
- It is commonly seen in a racial isolate area in the state of Maryland.
- It affects both dentitions.
- Clinically the disease is same as type I and type-II variants, however it often exhibits multiple pulp exposures and periapical lesions in deciduous teeth.
Clinical Features Dentinogenesis Imperfecta
- In all three types of dentinogenesis imperfecta both deciduous and permanent dentitions are affected with variable clinical presentations.
- The condition affects males and females with almost equal frequency.
- On eruption, the teeth exhibit a normal contour but they have an opalescent ‘amber-like’ appearance.
- Few days after eruption, the teeth may achieve an almost normal color, following which they become translucent.
- Finally the teeth become either gray or brownish in color with a bluish reflection from the enamel.
- The overlying enamel is structurally normal in most cases, however it is lost rapidly from the surface soon after the teeth have erupted and as a result the teeth often develop severe attrition.
- In some cases of dentinogenesis imperfecta, the affected teeth may also exhibit hypomineralized areas on the surface enamel.
- Teeth are not particularly sensitive even when most of the surface enamel is lost, it happens since the dentinal tubules are haphazardly arranged and most of them are devoid of the odontoblastic processes.
- Although the dentin is soft and easily penetrable in dentinogenesis imperfecta, these teeth are not caries prone. The possible reason could be the structural change in the dentin itself, which provides little scope for the entry of the cariogenic microorganisms into the tooth since most of the dentinal tubules are obliterated in this disease.
- Type III cases of dentinogenesis imperfecta are often associated with multiple pulp exposures (mostly due to attrition) and periapical pathology.
Radiographic Features
Radiographically dentinogenesis imperfecta reveals the following features:
- The type I and type II diseases are radiographically similar and they often exhibit “bulb shaped” or “bell shaped” crowns of the teeth with abnormally constricted cervical areas.
- The roots of the teeth are thin and spiked.
- Depending on the age of the patient, the teeth exhibit varying degrees of obliteration of the coronal as well as the radicular pulp chamber.
- The cementum, periodontal ligament and the alveolar bone radiographically appear normal.
- The type III dentinogenesis imperfecta may reveal radiographic features, which are similar to those of the type I and type II, although in many cases the affected teeth exhibit extremely large pulp chambers surrounded by a thin shell of dentin and enamel.
- Because of their typical appearance the affected teeth are often called “shell” teeth.
- These teeth frequently exhibit multiple pulp exposure and associated perapical pathology.
Histopathology
- Histologically the enamel appears normal in dentinogenesis imperfecta.
- The mantle dentin (a narrow zone of dentin immediately beneath the enamel) is also nearly normal.
- The major parts of the remaining dentin are severely dysplastic and exhibit vast areas of amorphous matrix with globular or inter-gobular foci of mineralization.
- The dentinal tubules are far less in number per square unit area of dentin as compared to the normal dentin.
- These tubules are often distorted, irregular in shape, widely spaced and are often larger in size.
- In many cases the odontoblast processes are absent in the dentinal tubules, instead there can be presence of some degenerating cellular debris in them.
- There may be large areas of atubular dentin present.
- The pulp chamber and root canals are often obliterated by abnormal dentin deposition.
- The dentino enamel junction appears smooth or flattened instead of being scalloped. This abnormal configuration is mostly responsible for the early chipping of enamel from the tooth surface in dentinogenesis imperfecta.
Biochemical Property of Dentine
- Biochemical analysis of the dentine in dentinogenesis imperfecta reveals increased water content and decreased mineral content.
- The microhardness of the dentin is low as compared the normal dentine.
Treatment
The treatment in dentinogenesis imperfecta is mostly aimed at preventing excessive tooth attrition and improving esthetics of the patients.
- Metal and ceramic crowns are given.
- These teeth are not suitable candidates for playing the role of abutments for any bridge work since the roots are small and they also tend to fracture under frictional stress.
- In case of severe generalized attrition, complete denture prosthesis may be necessary.
DENTINAL ABNORMALITY DUE TO SYSTEMIC OR ENVIRONMENTAL DISTURBANCES
The environmental or systemic conditions, which can affect dentinogenesis are as follows:
- Vitamin-D dependent rickets.
- Vitamin-D resistant rickets.
- Cytotoxic drugs.
- Juvenile hypoparathyroidism.
- Hypophosphatasia.
Vitamin-D Dependent Rickets
Dentinal features include:
- The width or thickness of the predentin is increased.
- Improper and incomplete calcification of the regular dentin.
- Thick band like areas of inter globular dentin can be seen histologically, which correspond to the periods of active phase of the diseases.
Vitamin-D Resistant Rickets (Hypophosphatemia)
Feature
- Increased amount of interglobular dentin formation.
- These teeth exhibit large pulp chambers and long pulp horns. The later may even extend to the dentino enamel junction as narrow clefts.
- The overlying enamel is defective and shows numerous cracks, which can serve as the direct pathways for entry of microorganisms into the pulp.
- Many such teeth with this defect often exhibit pulpitis and periapical lesions even in the absence of caries.
Hypophosphatasia
- Increased formation of interglobular dentin.
- Widening of the predentine.
Cytotoxic Agents
Presence of many prominent incremental lines, which often correspond to the periods of the drug (cytotoxic) administration.
JUVENILE HYPOPARATHYROIDISM
Features
- Presence of smaller sized teeth in the arch.
- Hypoplastic enamel.
- Multiple prominent incremental lines can be seen in the dentine.
- Roots of the teeth are small.
- Histologically radicular dentine reveals many structural abnormally and there can be areas of vascular inclusions in the dentine.
DENTIN DYSPLASIA
Definition
Dentin dysplasia is an autosomal dominant inherited disorder characterized by defective dentine formation and abnormal pulpal morphology. The condition is also known as “root-less teeth”.
Types
The condition is classified into two-
- Type I or radicular dentin dysplasia.
- Type II or coronal dentin dysplasia.
DENTIN DYSPLASIA—TYPE-I
Dentin dysplasia type-I represents a peculiar disturbance in the development of radicular dentin.
Clinical Features
- There is no sex prediction.
- Although both types of dentin dysplasias are rare entities, however type-I dentin dysplasia is far more common than type-II.
- The anomaly affects both dentitions.
- Although the roots of the teeth are defective, the crown portions are normal both structurally and morphologically.
- The color of the teeth is usually normal but in some cases the crowns of the teeth reveal a slight bluish or brownish translucency at the cervical region.
- Unlike dentinogenesis imperfecta the enamel does not chip off from the crown surface.
- The teeth usually erupt at the normal time; although in some cases there can be delayed eruption.
- Because of the presence of functionally unstable short roots, the affected teeth often exhibit severe mobility and they may exfoliate prematurely.
- Dentin dysplasia type-I can occur in association with diffuse generalized osteosclerosis.
Radiographic Features
- The roots of the teeth are characteristically short, blunt or conical.
- Although presence of rudimentary roots are common, in many cases the teeth may be completely devoid of roots.
- The deciduous teeth often exhibit total obliteration of the pulp chambers and root canals.
- The permanent teeth also present pulp obliteration but often there is presence of very thin crescent shaped remnants of the pulp chamber.
- The mandibular molars often exhibit characteristic “W” shaped roots.
- Periapical radiolucencies of unknown etiology may affect many teeth.
Histopathology
- The enamel and mantle dentins are normal.
- The remaining coronal and radicular dentin appear as a fused nodular mass comprising of tubular dentin and osteodentin.
- Histologic appearance of such defective mass of dentinal tissue often resembles what is called “a series of sand dunes” or “lava flowing around boulders”.
- Remnants of pulp tissue may occasionally be seen between the normal and the abnormal dentinal tissue.
- The normal and the abnormal dentin are well demarcated and the later reveals an abnormal distribution and orientation of the dentinal tubules with a typical whorled appearance.
Pathogenesis
Dentin dysplasia type – I develops probably due to a defect in the epithelial root sheath of Hertwig, which fragments and becomes incorporated into the dental papilla where it induces formation of dysplastic dentin.
Treatment
No specific treatment is available. These teeth also do not serve as good abutments since their roots are very short.
DENTIN DYSPLASIA TYPE-II
Definition
It is an inherited autosomal dominant disorder of dentine, which mostly affects the coronal dentine.
Clinical Features
- Both deciduous and permanent teeth are affected in this disorder.
- The permanent teeth are of normal color, whereas the deciduous teeth exhibit an “amber-grey” color with some translucent or opalescent appearance.
- There is no sex predilection.
Radiographic Features
- The deciduous teeth in dentin dysplasia type II reveals obliterated pulp chambers and root canals, thereby resembling dentinogenesis imperfecta.
- Pulpal obliteration occurs only after tooth eruption.
- The roots of the deciduous and the permanent teeth are usually of normal shape and length.
- Unlike dentinogenesis imperfecta there is no cervical constriction of the teeth in dentin dysplasia type-II.
- The pulp chambers in permanent teeth are abnormally large instead of being obliterated and have a typical flame shape.
- The pulp chamber contains many pulp stones or denticles.
- Root canals may be partially obliterated in the apical third region.
Histopathology
- The deciduous teeth exhibit a dense amorphous mass of dentin, which contains only few haphazardly arranged dentinal tubules.
- The permanent teeth show normal dentinal structures but may have the presence of abnormal globular or inter globular dentin near the pulpal third area and in the roots.
- The pulp chambers exhibit the presence of numerous pulp stones.
Treatment and Prognosis
No special treatment is required in case of dentin dysplasia type-II. Prognosis is good for the permanent teeth since their root length is essentially normal.
REGION ODONTODYSPLASIA (GHOST TEETH)
Definition
Regional odontodysplasia is an uncommon but unique non-hereditary developmental disturbance of teeth characterized by defective formation of enamel and dentin in addition to abnormal pulp and follicle calcifications.
Etiology
The etiology is not fully understood but it is suggested that the disease develops due to some local ischemic change in the tissue during odontogenesis.
Clinical Features
- Both permanent and deciduous dentitions are affected in this disease although it is more common in permanent dentition.
- There is no sex predilection.
- The maxilla affected more often than mandible.
- The disease is called regional since it affects several contiguous teeth in a single quadrant.
- It frequently occurs unilaterally, often affecting certain parts of the maxilla.
- The central and lateral incisors and the cuspids in the maxillary arch are often affected.
- The affected teeth show either delayed eruption or a complete failure of eruption.
- These teeth are often deformed, have a soft leathery surface and are yellowish-brown in color.
Radiographic Appearance
The teeth is regional odontodysplasia have often been described as “ghost teeth”, since there is marked decrease in the radio density of these teeth as a result of defective mineralization.
- The enamel and dentin are very thin and radiographic distinction between these two structures are impossible, this accounts for the subdued or “ghostly” appearance of the involved teeth.
- Pulp chambers of the teeth are extremely large and open, and often they contain pulp stones.
Histopathology
- The enamel layer is attenuated and disrupted.
- Dentin is very thin and globular, and exhibits irregular tubules and a wide predentine layer.
- Large pulp chamber exhibits numerous pulpal calcifications.
- The reduced enamel epithelium persists and the follicular connective tissue contains numerous clusters of tiny droplet calcifications.
Treatment
Extraction of the affected teeth and fabrication of a suitable prosthesis is usually recommended.
DISTURBANCE IN STRUCTURE OF CEMENTUM
Cementum is the odontogenic mesenchymal tissue, which covers the root surface of teeth. There are two types of cemental tissues found:
The acellular or primary cementum Which covers the coronal one third of the roots.
The cellular or secondary cementum It covers the apical two thirds and furcation areas of the teeth. The cellular cementum often has a thicker layer and it continues to form throughout the life of the tooth.
There are two main types of defects seen in the cementum:
- Hypercementosis.
- Hypocementosis.
HYPERCEMENTOSIS
Definition
It represents an increased and abnormal thickness of the cementum, which results from abnormal cementogenesis.
Etiology
Periapical Inflammation
Periapical inflammation causes cemental resorption at it's centre position, however this also causes cemental opposition on the root a little further away. This may result in either a generalized increase in the thickness of cementum or a localized “knob-like” enlargement.
Mechanical Stimulation
Although excessive mechanical forces applied to tooth produce cemental resorption but forces below a certain threshold level may stimulate cemental apposition.
Non-functional and Unerupted Teeth
These teeth sometimes show cemental resorption but excessive apposition of cementum is also possible.
Paget's Disease of Bone
Hypercementosis is a common feature of Paget's disease of bone. The cementum in this disease is very thick and it often has a mosaic pattern.51
Root Ankylosis and Concrescence
Teeth in these conditions may be associated with hypercementosis.
HYPOCEMENTOSIS
Hypocemtosis or acementosis is a rare developmental anomaly of tooth.
Cause
- Cleidocramial dysplasia
- Hypophosphatasia.
Hypocementosis prevents the normal development of the periodontal attachment or even the normal dentin formation. Premature loss of few or all deciduous and permanent teeth may occur in this disease.
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