The hyperdivergent forms of Class II dentoskeletal dysmorphosis are difficult conditions to treat. The purpose of this study is to describe and assess a technical stratagem which lowers the bite plane in its posterior section by means of a sagittal osteotomy of the mandibular rami. The procedure is performed to correct a Class II with deficient mandibular ramal development.

In the course of a sagittal osteotomy of the mandibular rami, a complete section of the pterygo-masseter muscle complex is performed. Fifteen patients receiving surgery for Class II malocclusion with inadequate mandibular ramal height are clinically assessed using radiography and cephalometry.

In all fifteen cases, the occlusal plane was lowered in its posterior portion. Both vertical and sagittal occlusal results were stable. Elongation of the ramus as such is more difficult to demonstrate. Sagittal osteotomy of the mandibular rami with complete section of the pterygo-masseter sling lowers the bite plane in cases with mandibular posterior vertical deficiency. This technique avoids an external approach and belongs to the armamentarium aimed at treating this type of dysmorphosis.