THE PRINCIPAL MODE OF ACTION OF FUNCTIONAL APPLIANCE AHMAD HAMZI HAMI MUHAMAD SYAFIQAH NADHIRAH ISKANDAR ABDULLAH ZAHID AZHARI AKMAL KHALIS DOREYAT IDHAM HAFIZE SUPI AWATIF ASRI

Basis of its work: The grows of the mandible is guided (particularly in the anterior and vertical directions) but the grows of the maxilla is also affected.

MOA of FA DENTOALVEOLAR EFFECT SKELETAL EFFECT SOFT TISSUE EFFECT

DENTOALVEOLAR EFFECT (COMPENSATION) Under the influence of favourable soft tissues, Class II malocclusions The lower incisors may be proclined and the upper retroclined Class III malocclusions The upper incisors may be proclined and the lowers retroclined These dentoalveolar compensation is to compensate for the sagittal skeletal discrepancy. Dentoalveolar compensation is a static snapshot of occlusal adaptation, produced by favourable soft tissue, which masks the severity of an underlying discrepancy either in anteroposterior, vertical or transverse dimension.

Vertical relationship DENTOALVEOLAR EFFECT (VERTICAL RELATIONSHIP) In case of skeletal open bite To maintain the normal overbite, the posterior dentoalveolar segment intrudes. The anterior dentoalveolar segments extrudes. In case of skeletal deep bite The posteriors can extrude or the anteriors can intrude to maintain a normal overbite.

Transverse relationship DENTOALVEOLAR EFFECT (TRANSVERSE RELATIONSHIP) A discrepancy between a narrow maxillary base and a wide mandibular base buccal tilting of upper teeth and lingual tilting of lower teeth. A discrepancy between wide maxillary base and narrow mandibular base lingual tilting of upper teeth and buccal tilting of lower teeth.

SKELETAL EFFECT The skeletal changes can be considered in two dimensions, namely anteroposterior and vertical. Increased mandibular length. - due to downward and forward translation of the condyle which may encourage backward compensatory growth. - a change in the position and direction of the mandibular condyle and glenoid fossae (forward remodelling of the glenoid fossa- secondary to anterior condylar repositioning). - accelerated growth of the mandible, but not necessarily additional growth. Restraint of maxillary grows. -due to the Class II traction forces acting on maxilla. Incorporation of headgear into functional appliance treatment increases this effect.

SOFT TISSUE EFFECT Some functional appliances have the long-term effect on the soft tissues. Functional regulator appliances in combination with lip exercises might influence the position and functions of lips and cheeks to move the teeth into correct position.