INTRODUCTION
The first law of success is … concentration to bend all the energies to one point and to go directly to that point.
Removable mechanical appliances used to move a tooth has same principle. Regardless of the number of trained specialists and the popularity of fixed appliances it seems that much treatment will be carried out by general practitioner rather than specialist. Removable appliances make a valuable contribution in orthodontic service. If used in selected cases with perfection it gives good results.
In order to use any appliance to the best advantage, it is essential, for the operator to match appliance design to the required tooth movement and to maintain effective control of clinical treatment.
A removable appliance will only perform their tasks satisfactorily if they are worn continuously. For this not only the patient should be enthusiastic and co-operative but the operator also has a duty to design and construct the appliance that they can be readily tolerated by such a patient.
Simple tilting movements can be easily carried out and teeth may be tipped mesially, distally, buccally or lingually.
Removable appliances can correct the rotations upto 45°. Extrusive and intrusive teeth movement for correction of the bite also can be carried out.
Good anchorage is provided by removable appliances usually it is obtained from the same arch, i.e. intramaxillary.
Scope of removable appliances is much better than fixed appliances because patient has a much happier attitude, it requires less time to prepare and adjust, patient gets less pain which is important for cooperation. It can be said that results achieved with removable appliances are simply:
- Beautiful with facial esthetics
- Full complete smile
- Healthiest temporomandibular joints and best stability
To enhance the field of removable appliances it is necessary to invent the new ideas and new designs to make it more convenient and faster.
Horse power has to put it on the ground to do any good for the dentist who wants to “Put it in the mouth” the hundreds of design and fabrication aid in reaching the goal.
As early as first century AD Celsus reported that erupting first malposed teeth could be directed into their proper place by pressure from finger.
First advocate of removable appliances in the Modern sense was given by F Ch Kneisel (1836) at Berlin, who wrote DER Schiefstand der Zahne (Malposition of the teeth) described about chin cap for C1 III, modern impression trays and appliances for teeth movement
John Tomes (1845) used first removable plate. It was made up of metal and equipped with elastic springs. This is available at famous collection of Academy of Medicine in New York(Fig. 1.1).
JD White (1854) developed early removable plate of rubber or vulcanite.
Coffin (1881) used upper expansion spring for the first time. It consists of a vulcanite base plate with molar capping incorporating a spring of piano wire bent in shape of letter ‘W’ (Fig. 1.2).
Talbot (1888) used lower appliance using same principle but with the wire bent in a ‘U’ shape.
Robin (1902) was first to use modern stabilized expansion screw instead of the coffin spring.
Kingley (1880) pioneer of modern functional jaw orthopedics used bite plate with an inclined anterior plane to move the mandible forward by jumping the bite.
CA Hawley (1919) used his plates for minor teeth movement and as a retainer.
VH Jackson (1911) designed a skeletal like removable appliance.
JF Colyer's (1908) in United Kingdom used piano wire for appliance. Appliances consists of a vulcanite base plate covering the palate and capping the molars and premolars for retention. Lower teeth are allowe to bite into the vulcanite, bite being registered with an articular (Fig. 1.3).
Bennett (1914) published The Science and Practice of Dental Surgery. He had mentioned about removable appliances. Vulcanite or metal base plate is used. Metal plate being preferred since they were less bulky. Cast silver or gold or struck nickel were used clasps of platinized gold wire were used for retention.
Bedcock (1911) introduced his screw expansion plate in British Society for Study of Orthodontics. Screw was made of nickel silver. It corrodes slowly in mouth but has germicide property which is helpful in prevention of carrier.
CFL Nord (1929) presented very simple screw split plate meant for treatment at the meeting of the European Orthodontic Society in Heidelberg.
M Tischler (1936) demonstrated quite sophisticated active plate at the Ninth International Dental Congress in Vienna.
AM Schwarz (1938) who is the father of active plates had published his textbook on active plates in Vienna Australia. He introduced tranverse and sagittal appliances.
National Health Service Bill was published in 1946 and came into effect in July 1948 inspiring the rapid development of removable appliances. This is due to introduction of acrylic resin to replace vulcanite and development of Adam Clasps.
Adam (1950) first demonstrated his modified arrowhead clasp. This clasp used mesial and distal undercuts of teeth and can be used to clasp a single tooth, fully or partially erupted. Small, unobstructive which took up little space in buccal sulcus and no special pliers were required for its construction.3
Secure and reliable retention of appliance was easily achieved.
Ballard and Wayman (1964) treated majority of malocculesions with removable appliances (Fig 1.4).
Mill and Vig (1974) expressed the opinion that although removable appliances were unsatisfactory to correct rotations or closure or larger spaces. They have advantage that is economical, simple to make providing sufficient anchorage. Useful in treatment of malocclusions where only Hpping is required.
Steadman (1925) advocated planned extractions to avoid need for appliances.
Visick (1929) was also in favour of removable appliances for simple tooth movements.
Marsh (1930) was also using removable appliances.
Culter (1932) reported to the British Society for study of orthodontics or preparations of stainless steel in Germany and Great Britain.12
Piano wire was recommended where strength and elasticity were required but problem of corrosion.
Packham (1932) solved problem of corrosion by fining the wire before use.
Gold wire is also used.
A British company Firth were producing an austentic stainless steel which cost 10 shillings per pound while gold was 145 rouble per pound.
Stainless steel was discovered by Brearley of Sheffield which is widely used nowadays. It has got many advantages over gold wire.
Osbourne (1941) reported in the British Dental Journal that acrylic had become available as a liquid monomer and powder polymer.
Hallett (1952) introduced cold curing resin for preparation of base plates.
Cousins (1962) used this cold cure acrylic resin to prepare complete orthodontic removable appliance plate.
Roberts (1976) introduced pressure moulding technique to prepare plates. This process uses hot compressed air to mould acrylic base plate blanks on to a plaster model to which the wire components have been attached.
Victor Hugo Jackson (1887) published lateral expansion appliance for lower arches.
Dr Emest Walker of New Orleans developed appliance made of gold and platinum wires.
Dr George B Crozat (1916) who graduated from Devays School of Orthodontia. Crozat designed his appliance in New Orleans in 1919.