Textbook of Orthodontics Gurkeerat Singh
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1NORMAL GROWTH
  1. Introdution to Orthodontics
  2. Basic Principles of Growth
  3. Prenatal Growth of Cranium, Facial and Oral Structures
  4. Postnatal Growth of the Craniofacial Complex
  5. Development of Dentition
  6. Occlusion in Orthodontics
    2

Introduction to Orthodontics1

Gurkeerat Singh
  • ■ What is orthodontics?
  • ■ Branches of orthodontics
  • ■ Aims of orthodontic treatment
  • ■ Scope of orthodontics
  • ■ History of orthodontics
 
WHAT IS ORTHODONTICS?
What does the common man associate with the term orthodontics? It is a special branch of dentistry which deals with the alignment of teeth. What people perceive of this branch of dentistry is what we as dentists project of the capabilities of an orthodontist.
Orthodontics has been defined by Salzmann (1943) as ‘a branch of science and art of dentistry which deals with the developmental and positional anomalies of the teeth and the jaws as they affect oral health and the physical, esthetic and mental well being of the person.’ This definition may be over fifty years old yet even at that time the potential of orthodontics was not lost. The emphasis is on maintenance of oral, physical and mental health of the patient and also his/her esthetics.
Yet, this was not the first definition proposed. Definitions proposed earlier had also recognized the importance of the knowledge of growth and the essentiality of correcting aberrations as early as possible. In 1911, Noyes defined orthodontics as “the study of the relation of the teeth to the development of the face, and the correction of arrested and perverted development.”
This definition was further modified when in 1922 the British Society of Orthodontists proposed that “Orthodontics includes the study of growth and development of the jaws and face particularly, and the body generally, as influencing the position of the teeth; the study of action and reaction of internal and external influences on the development, and the prevention and correction of arrested and perverted development.”
The definitions now recognise the importance of growth but also associate it with etiology and the purpose of orthodontics—to create and maintain a normal environment and proper physiologic activity of the teeth, the soft oral tissues, the facial and masticatory musculature, in order to ensure as far as possible optimum dentofacial development and function. The use of the word prevention before correction symbolizes the need to diagnose a problem as soon as possible.
The definition of orthodontics proposed by the American Board of Orthodontics (ABO) and later adopted by the American Association of Orthodontists states:
Orthodontics is that specific area of the dental profession that has as its responsibility the study and supervision of the growth and development of the dentition and its related anatomical structures from birth to dental maturity, including all preventive and corrective procedures of dental irregularities requiring the repositioning of teeth by functional and mechanical means to establish normal occlusion and pleasing facial contours.”
The American Board of Orthodontics’ definition recognizes the capability of the orthodontists in being able to change the profile by not only moving teeth but also by redirecting growth using functional appliances. Hence, we see that the science has evolved over the years and its scope has been increasing along with our increased knowledge of the underlying biological principles of growth and development.4
 
BRANCHES OF ORTHODONTICS
The art and science of orthodontics can be divided into three categories based on the nature and time of intervention.
  • Preventive orthodontics
  • Interceptive orthodontics
  • Corrective orthodontics.
 
PREVENTIVE ORTHODONTICS
Preventive orthodontics, as the name implies, is action taken to preserve the integrity of what appears to be the normal occlusion at a specific time. Preventive orthodontics requires the ability to appraise normal dentofacial and general development and growth and the recognition of deviations from the normal. It entails the elimination of deleterious local habits involving dentofacial structures; the correction of general contributory causes, such as incorrect posture and malnutrition; the maintenance of tooth form by proper restoration of individual teeth; timely removal of retained deciduous teeth; use of space maintainers after premature loss of deciduous teeth, if indicated, and reference for treatment of related affections and abnormalities to other specialists.
 
INTERCEPTIVE ORTHODONTICS
According to the definition given in the brochure on orthodontics by the American Association of Orthodontists, Council of Orthodontic Education, is “that phase of the science and art of orthodontics, employed to recognize and eliminate potential irregularities and malpositions in the developing dentofacial complex”. This phase specifically concentrates on its efforts towards improving environmental conditions to permit future normal development. The preventive measures envisaged may include caries control, anatomical dental restorations, space maintenance, transitory oral habit correction, genetic and congenital anomalies, and supervising the exfoliation of deciduous teeth.
Certain procedures under the preventive and interceptive orthodontic fields may overlap. Hence, at times it may not be possible to segregate the two, however, interception always recognizes the existence of a malocclusion or malformation whereas the prevention is aimed at preventing the malocclusion or malformation from occurring.
 
CORRECTIVE ORTHODONTICS
Corrective orthodontics, like interceptive orthodontics, recognizes the existence of a malocclusion and the need for employing certain technical procedures to reduce or eliminate the problem and the attendant sequelae. The procedures employed in correction may be mechanical, functional or surgical in nature.
 
AIMS OF ORTHODONTIC TREATMENT
The treatment provided should not only satisfy the patient's esthetic desires but also satisfy certain functional and physiologic requirements. Jackson had summarized the aims of orthodontic treatment as:
  • Functional efficiency
  • Structural balance
  • Esthetic harmony
These three are now famous as the Jackson's triad.
 
FUNCTIONAL EFFICIENCY
The teeth along with their surrounding structures are required to perform certain important functions. The orthodontic treatment should increase the efficiency of the functions performed by the stomatognathic system.
 
STRUCTURAL BALANCE
The structures affected by the orthodontic treatment include, not only the teeth but also the surrounding soft tissue envelop and the associated skeletal structures. The treatment should maintain a balance between these structures, and the correction of one should not be detrimental to the health of another.
 
ESTHETIC HARMONY
The orthodontic treatment should increase the overall esthetic appeal of the individual. This might just require the alignment of certain teeth or the forward movement of the complete jaw including its basal bone. The aim is to get results which gel with the patient's personality and make him/her to look more esthetic.
 
SCOPE OF ORTHODONTICS
Orthodontic treatment is aimed at moving teeth, orthopedic change and altering the soft tissue envelop.5
 
MOVING TEETH
The main reason for the existence of this specialty was it's capability of moving teeth. Moving teeth without any deleterious effects into more ideal locations is what everyone always associates this field with. How efficiently this can be undertaken and to what extent, depends upon the nature of the malocclusion and the capability of each individual clinician.
 
ORTHOPEDIC CHANGE
Using functional appliances and the latest orthognathic techniques, it is possible to move entire jaws into more favorable positions. It is very much within the capabilities of an orthodontist to use appliances at times in conjunction with other specialists to move the entire jaws along with its basal bone and the soft tissue envelop to achieve the objectives of treatment.
 
ALTERING THE SOFT TISSUE ENVELOP
The functions performed by the soft tissue envelop of the teeth and the oral cavity have a definite impact on the growth and development of the oral and facial structures. The orthodontist can help retain or restrain the soft tissues and or bring about a change in them by altering the position of the teeth or the jaws. The various functional appliances and at times habit breaking appliances may be used along with other treatment procedures.
 
HISTORY OF ORTHODONTICS
Hippocrates (460–377 BC) was the first to draw attention towards the association of teeth to jaw structures. In his writings are the lines “Among those individuals whose heads are long shaped, some have thick necks, strong members and bones, others have strongly arched palates, thus teeth are disposed to irregularity, crowding one on the other and they are molested by headaches and otorrhea.”
The first recorded method of treatment was that of Celsius (125 BC-AD 50). He recommended that—“If a second tooth should happen to grow in children before the first has fallen out, that which ought to be shed is to be drawn out.”
The first mechanical treatment for correcting irregularities was suggested by Gaius Plinius Secundus (Pliny) (AD 23–79). He advocated the filing of elongated teeth to produce proper alignment.
Paul of Aegina (AD 625–690) was the first to mention supernumerary teeth.
Piette Dionis (1658–1718) was the first to mention “separators for the teeth,—to open or widen the teeth when they are set too close together.” He also, commented on the etiology of dental irregularity.
Matthacus Gottfried Purmana, in 1692 was the first to mention casts in dentistry. He used wax, as the impression material.
Plaster of paris for impressions were first reported in 1756, by Phillip Pfall.
Kneisel, in 1836, published the first book (in German) on malocclusion of the teeth. It was entitled, Der Schiefstand der Zahne. Kneisel attempted the first classification of malocclusion and was the first to advocate the use of removable appliances. He also introduced the modern impression tray.
Pierre Fauchard was the first to use the title “surgeon-dentist.”
Fauchard (1728) gave to the orthodontics the “bandelete” later known as the “expansion arch.”
In 1743 Bunon first used the term orthopedics in connection with the correction of malocclusion.
John Hunter (1728–1793) wrote at length about irregularities of teeth and their correction in his book—natural history of human teeth (1771 and 1778).
Joseph Fox wrote two books (1803 and 1806) in which he gave explicit directions for the correction of malocclusions.
In 1825, Joseph Sigmond recognized habit as a factor in malocclusion.
Thumbsucking as a cause of dental abnormalities was first mentioned by William Imrie in 1834.
Term orthodontia was used originally by Lefoulon in 1839. According to Lischer, the term orthodontics was first used by Sir James Murray. The term orthodontics was formally defined by Schelling in 1909.
In 1841, JMA Sehange of France contributed articles on orthodontics. He described a clamp band in which a screw was employed for tightening the band to the tooth.
In 1859, Norman William Kingsley presented the first obturator to a cleft palate patient.
The first outstanding work devoted exclusively to orthodontics was written by John Nutting Farrar (1839–1913) aptly titled—‘Treatise on Irregularities of the Teeth and their Correction.’6
In 1887 EH Angle presented his classification of malocclusion.
In 1900, Edward H Angle started his first school of orthodontics in St. Luise. He developed the “E” arch, the pin and tube appliance, the ribbon arch appliance and the edge-wise appliance. He was a proponent of the non-extraction school of thought.
Calvin S Case in 1892 stressed the importance of root movement and was one of the first to use elastics for treatment. In 1917 he advocated the use of light resilient wires. He opposed the Angle school of universal applicability of the normal occlusion theory and advocated extractions as part of orthodontic treatment.
Martin Dewey (1914) wrote the book—‘Practical Orthodontics’. He founded the International Journal of Orthodontics (now the American Journal of Orthodontics and Orthopedics).
In the 1930s Raymond Begg presented the Begg appliance (light wire differential force technique). It was a modification of the ribbon arch appliance, but used extremely light forces for treatment.
There were many more contributors to the field of orthodontics. And as the vast possibilities of this science are unfolding, they are still emerging. The basic difference is that the American school is continuing with the improvement in fixed appliances whereas the European school concentrated more on the removable and functional appliances. Now the world has become so small that contributors to this science are not restricted to regions and techniques. Although it is better to work within one's limit, one also learns from the experience of others.
FURTHER READING
  1. Enlow DH, Hans MG. Essentials of Facial Growth, Saunders  Philadelphia,  1996
  1. Graber TM. Orthodontics: Principles and Practice, ed. 3, WB Saunders,  1988.
  1. Moyers RE. Handbook of Orthodontics, ed. 3,   Chicago,  1973, Year Book.
  1. Salzmann JA. Practice of Orthodontics, J B Lippincott Company,  1996.
  1. White TC, Gardiner JH, Leighton BC. Orthodontics for Dental Students, 3rd ed., Macmillan Press Ltd,  1976.
  1. White TC, Gardiner JH, Leighton BC, Valiathan A. Orthodontics for Dental Students, 4th ed., Oxford University Press,  Delhi,  1998.