Functional Appliances

These are powerful appliances capable of impressive changes in the position of the teeth. They are generally used for Class II Division I malocclusions although they can be used for the

Fig. 12c Upper first and lower second premolars were extracted and the canines surgically exposed

Trihelix Appliance

Fig. 12d A tri-helix was used to expand the upper arch and a sectional fixed appliance used to pull the canine into the line of the arch

Ecosystem Buccal

Fig. 12a, b Pre treatment photographs of a patient with palatally impacted canine, a buccal cross bite, an increased overjet and crowding in both arches

Fig. 12e Full fixed appliances were then used to reduce the over bite and overjet, move the apex of the canine into the line of the arch and correct all the other features of the malocclusion. The initial arch wire was a very thin flexible wire. If a thick wire is used at this stage excess force will be applied to the teeth that can produce root damage and be very painful for the patient

Fig. 12e Full fixed appliances were then used to reduce the over bite and overjet, move the apex of the canine into the line of the arch and correct all the other features of the malocclusion. The initial arch wire was a very thin flexible wire. If a thick wire is used at this stage excess force will be applied to the teeth that can produce root damage and be very painful for the patient

^ Figs 12f,g Once initial alignment of the teeth is produced = progressively thicker, stiffer wires are employed. Because these fit the bracket slot more closely they control tooth position more precisely than the thinner aligning wires

Fig. 12h,i The completed case. The canine is fully aligned and the overjet reduced without any unwanted tipping of the teeth

Fig. 12j Appropriate extractions and treatment mechanics have not been detrimental to the facial appearance correction of Class II Division II and Class III malocclusions on occasion. They are either removable from the mouth or fixed to the teeth, and work by stimulating the muscles of mastication and soft tissues of the face. This produces a distalising force on the upper dentition and an anterior force on the lower. Whilst they are capable of substantial tooth movement, like all removable appliances they are not capable of precise tooth positioning and cannot deal effectively with rotations or bodily tooth movement.

There is some controversy as to the precise mode of action of functional appliances. Some clinicians feel they have an effect on this facial skeleton, promoting growth of the mandible and/or maxilla. Others feel that the effects are mainly dento-alveolar and that the results achieved are accomplished by tipping the upper and lower teeth. Unfortunately many of the studies relating to functional appliance treatment have been poorly constructed and their conclusions should be treated with caution. A large-scale, prospective, randomized clinical trial currently being undertaken in United Kingdom strongly suggests that 98% of the occlusal

Fig. 13 Bodily movement of the teeth requires a greater degree of force than tipping movements

Fig. 14a,b Pre-treatment photographs of a 12-year-old girl with an increased overjet and a class II skeletal pattern associated with a retrognathic mandible

Extraoral Myofunctional Appliances

Fig. 14c A functional appliance was used to correct the saggital relationship

Sun Damaged Skin
f Fig. 14e,f The facial appearance following treatment

Fig. 14d The final result after detailing of the . occlusion with fixed appliances

Fig. 14d The final result after detailing of the . occlusion with fixed appliances

Extraoral ApplianceExtraoral Forces
Fig. 15 Extra-oral traction applied via an Interlandii headgear
Appliance Headgear

correction is by tipping of the teeth with an almost negligible effect on the skeletal pattern.5 Nevertheless, dramatic occlusal changes are possible with these appliances and they can aid the correction of some quite severe malocclusions. Figures14a-f show a case treated with a functional appliance that had a marked effect not only on the occlusion but also on the patient's facial appearance.

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