Objective: The purpose of this study was to evaluate whether postsurgical stability differs after orthognathic surgery with bilateral intraoral vertical ramus osteotomy (IVRO) in skeletal Class III patients with and without nonsurgical miniscrew-assisted rapid palatal expansion (MARPE)
Methods: The subjects were retrospectively divided into two groups (n = 20 each) according to whether MARPE was used to correct a maxillomandibular transverse discrepancy during presurgical orthodontic treatment. Serial lateral cephalometric radiographs and dental casts were analyzed until 6 months after surgery.
Results: Before presurgical orthodontic treatment, the control and MARPE groups did not differ significantly with regard to sex and age. However, the maxillomandibular intermolar width difference of about 3.1 mm was statistically significant (P < 0.001). Two days after surgery, the mandible was moved backward and upward without any significant intergroup difference. Six months after surgery, in the MARPE group, the maxillary intercanine (2.7 ± 2.1 mm), interpremolar (3.6 ± 2.4 mm), and intermolar arch widths (2.0 ± 1.3 mm) significantly increased (P < 0.001) compared to those before presurgical orthodontic treatment, but the widths were maintained or decreased in the control group. However, there was no difference in surgical changes and postsurgical stability between the two groups. No significant correlations existed between the amount of maxillary expansion and postsurgical mandibular movement.
Conclusions: In skeletal class III adult patients with a transverse maxillary deficiency, which requires bimaxillary surgery, MARPE can be used for the stable and nonsurgical expansion of the maxilla.

Keywords: Miniscrew-assisted rapid palatal expansion, Maxillomandibular transverse discrepancy, Mandibular prognathism, Skeletal Class III, Stability