Evaluation of Skeletal Stability After Surgical-orthodontic Correction of Skeletal Open Bite with Mandibular Counterclockwise Rotation Using Modified Inverted L Osteotomy

Purpose: To evaluate the surgical-orthodontic stability of treating skeletal open bite patients with mandibular ramus osteotomies using a modified inverted L osteotomy (M-ILO) and counterclockwise rotation of the mandible stabilized with rigid fixation.

Patients And Methods: In a retrospective review, 12 patients with skeletal open bites (8 females, 4 males) who received mandibular M-ILO in the period 2004-2007 at Tohoku University Hospital were studied. Lateral cephalograms were taken immediately before surgery (T1), immediately after surgery (T2), and at 1 yr after surgery (T3). Cephalometric analysis for point B, pogonion, menton, and mandibular plane angle was obtained at the designated time intervals.

Results: Mandibular counterclockwise rotation showed stability for point B, pogonion, and menton referred to X-Y coordinate, and for mandibular plane angle. The mean value for each variable was compared between T2 and T3. No statistically significant change was observed for all variables.

Conclusions: With a well-positioned maxilla, skeletal open bite can be successfully treated using M-ILO. Mandibular counterclockwise rotation showed stability at 1 yr after surgery.