A Case of Skeletal Class II Malocclusion with Severe Unilateral Scissors Bite

Abstract

A 33-year-old female had a class II malocclusion with a severe unilateral scissors bite. Initial records showed the overerupted upper left premolars and molars, and lingo-inclined lower left premolars and molars. The lower first molars and the second molar of the right side were missing. The upper left molars impinged on the buccal gingiva of the lower arch in habitual occlusion. She also complained of difficulty of closing her lips. Orthodontic treatment followed by surgical procedures was performed. Extraction of the upper first premolars was performed at first for the elimination of crowding in the upper arch, and then one of these teeth was transplanted to the lower right posterior segment as the orthodontic anchor. After the alignment of the upper arch, the upper left posterior segmental osteotomy and the lower left posterior segmental corticotomy were performed for the correction of the scissors bite. The lower left posterior segment was expanded buccally after surgery, and then the upper and lower anterior segments were retracted orthodontically. Finally fairly good functional occlusion was obtained, and her lips could be competent at rest.