Surgically assisted rapid palatal expansion: is the pterygomaxillary disjunction necessary? A finite element study

Abstract

Transverse discrepancy is an important factor in determining facial esthetics. It has been shown there is an inverse correlation between the buccal corridor width and the intercanine and intermolar widths. Despite the fact midpalatal expansion is the treatment of choice for growing subjects, for skeletally mature subjects the rapid palatal expansion has limited orthopedic effects, and surgically assisted rapid palatal expansion (SARPE) is preferred. SARPE has shown inconsistencies depending on the surgical technique and/or expander device design. Some authors suggest that median and lateral osteotomies are sufficient to achieve the desired transverse dimensions using the SARPE procedure, while others recommend additional surgical separation of the pterygomaxillary junction. There are still controversies regarding the pterygomaxillary sutures (PMS) disjunction effect. Therefore, this study aimed to evaluate the displacement and stress distribution of the craniofacial structures resulting from SARPE, either with or without PMS osteotomy, using two different expander design (tooth-borne and tooth-bone-borne) using finite element method and finite element analysis (FEM/FEA). Regardless of the maxillary expander device type, both SARPE surgical techniques effectively produced maxillary expansion. SARPE with PMS osteotomy presented parallel maxillary expansion, and reduced stress values in the craniofacial and maxillofacial structures.