Title of the Study: Efficacy of Orthodontic Versus Surgically Assisted Transverse Maxillary Expansion in Adult Patient with Cleft Maxillary Hypoplasia—A Finite Element Method (FEM) Analysis

To assess the efficacy of surgically assisted maxillary expansion (PMO) in adult cleft patient with transverse maxillary hypoplasia by FEM analysis.

A 3-D FEM was created using CT scan of a patient unilateral cleft palate. The models were divided into three groups: orthodontic group, posterior maxillary osteotomy (PMO) group, and alveolar bone graft (ABG) group. Standardized force (5N—Hyrax and 2.94N—NiTi) was applied to the model to bring about required movement. The von Mises stress at the zygomaticomaxillary buttress, pterygomaxillary junction, frontonasal suture, midpalatal suture, internasal suture, piriform rim, and also the transverse displacement of the maxilla and impact on greater and lesser segment were evaluated.

In orthodontic group, von Mises stress area was more with NiTi palatal expander compared to Hyrax appliance.

In PMO group, negligible von Mises stress was observed on the cleft segment with maximum resistance observed in the premolar & 1st molar region of non-cleft segment.

In ABG group, addition stress was seen only at the graft site.

In orthodontic group, maximum von Mises stress was observed, and minimum displacement was seen because of fixed boundaries. In PMO group, minimum von Mises stress and maximum displacement were observed. In grafting & PMO group, von Mises stress was more at the graft site, & minimum displacement was observed. Thus, if grafting is necessary, it should be done after PMO.