Treatment of unilateralankylosis of the temporo-mandibular joint when a class II skeletal relationship exists

Summary If, in a case of ankylosis of the temporo-mandibular joint, a class II skeletal relationship exists, advancement of the mandible into a class I skeletal relationship should be an integral part of the treatment plan. The advantages are: better aesthetics (especially the appearance of the chin), more efficient action of the suprahyoid muscles (mouth openers), diminished contact of the angle of the jaw with the sterno-cleidomastoid muscle, increased distance of the lower incisors from the axis of rotation of the mandible (resulting in increased incisal distance at the same rotational angle) and the possibility of correction of the sometimes traumatic occlusion against the palatal mucosa all in the same session. The method advocated in unilateral cases is the insertionof a costo-chondral graft on the affected side and a lengthening osteotomy on the opposite side with fixation into a class I skeletal relationship initially disregarding the incisal relationship.