Anterior vertical osteotomy for mandibular narrowing: assessing short-term outcome

The management of transverse maxillomandibular discrepancies, clinically known as crossbites, is a controversial and rarely discussed topic in both orthodontic and surgical literature. To evaluate the short-term stability of mandibular narrowing after the combination of anterior vertical symphyseal and bilateral sagittal split osteotomies, a prospective cohort study was completed.

Between December 1996 and June 2006, 40 patients underwent mandibular narrowing for the correction of substantial transverse maxillomandibular discrepancies resulting primarily from relative mandibular widening. Stability assessment was done on 26 patients who returned for the final evaluation.

Follow-up periods ranged from 5 to 109 months (mean, 18 mo; N = 26). The stability of mandibular narrowing was evaluated by comparison of preoperative clinical assessment, lower dental impression, posteroanterior cephalogram, and occlusographic analysis with studies completed in the immediate postoperative period and at 6 to 12 months. At the short-term time point, mean mandibular location had relapsed 4.7 degrees in 21 patients.

Although various methods of mandibular narrowing are well described, very little literature has examined its stability. Using an occlusographic analysis based on angular mandibular movement in a large patient cohort, we were able to demonstrate and quantify, for the first time, the relapse. It occurs in 81% of the patients, with a mean of 4.7 degrees.