Posterior vertical deficiencies of the mandible: presentation of a new corrective technique and retrospective study of 21 cases.

PURPOSE: The hyperdivergent (high-angle forms of Class II) dentoskeletal deformities are difficult entities to treat. The purpose of this study was to describe and evaluate the use of a new surgical procedure to lower the posterior portion of the occlusal plane during a sagittal split osteotomy of the mandibular ramus, to correct a Class II malocclusion resulting from insufficient development of the mandibular ramus.

PATIENTS AND

METHODS

During a sagittal split osteotomy of the mandibular ramus, the pterygomasseteric sling was completely incised in 21 patients, to treat Class II malocclusion with vertical ramus deficiency. The patients were evaluated clinically, radiologically, and cephalometrically.

RESULTS

In all cases, the posterior occlusal plane was successfully lowered, with stable occlusal results, both vertically and sagittally. An increase in the vertical dimension of the ramus remains somewhat more difficult to document.

CONCLUSIONS

Sagittal split osteotomy of the mandibular ramus with complete incision of the pterygomasseteric sling makes it possible to lower the posterior occlusal plane in cases of posterior vertical mandibular deficiency. This technique, which offers a nonexternal approach, represents a useful additional option for the treatment of these dysmorphoses.