Mechanical Analysis Of Maxillary Expansion Using Rme And Mse

There are few studies which have explored the impacts of maxillary skeletal expander (MSE) on the entire craniofacial complex and evaluated the stress distribution of sutures. Thus, the purpose of this study is to compare the stress distribution of craniofacial complex and displacement of palatal suture and anchor teeth produced by MSE with that of conventional rapid maxillary expander (RME) using finite element analysis. A three-dimensional mesh model of craniofacial complex with associated sutures and models of RME and MSE were established. In finite element analysis, forces were applied on palatal surface to cause total 0.5mm of transverse displacement on the palatal halves. Magnitude and distribution of stress on craniofacial complex and displacement of mid-palatal suture and anchorage teeth were evaluated. The stress distribution of craniofacial complex with RME was located on maxillary frontal process, infraorbital margin, lateral wall of orbit, peripheral bone of pyriform foramen, pterygoid process and buccal alveolar bone of anchorage teeth. With MSE, the stress was highly concentrated around the four mini-implants, which of two frontal ones suffered more stress. Moreover, stress on pterygopalatine suture in MSE group was much greater than that in RME group, which may lead to more posterior expansion and nearly parallel expansion. MSE can overcome resistance from palatal and pterygopalatine suture and broaden mid-palatal suture and basal floor of nasal cavity more effectively, and we should give more attention to the frontal two mini-implants during maxillary expansion with MSE.