three dimensional finite element analysis of stress distribution and displacement of the maxilla following surgically assisted rapid maxillary expansion with tooth- and bone-borne devices

o bjectives: the aim of this study was to investigate the displacement and stress distri- bution during surgically assisted rapid maxillary expansion under different surgical conditions with tooth- and bone-borne devices. materials and methods: three-dimensional (3d) finite element model of a maxilla was constructed and an expansion force of 100 n was applied to the left and right molars and premolars with tooth-borne devices and the left and right of mid-palatal sutures at the first molar level with bone-borne devices. five cad models were simulated as fol- lows and surgical procedures were used:  g1: control group (without surgery); g2: le fort i osteotomy; g3: le fort i osteotomy and para-median osteotomy; g4: le fort i osteotomy and pterygomaxillary separation; and g5: le fort i osteotomy, para-median osteotomy, and pterygomaxillary separation. r esults: maxillary displacement showed a gradual increase from group 1 to group 5 in all three planes of space, indicating that le fort i osteotomy combined with para-me- dian osteotomy and pterygomaxillary separation produced the greatest displacement of the maxilla with both bone- and tooth-borne devices. surgical relief and bone-borne devices resulted in significantly reduced stress on anchored teeth. c onclusion: combination of le fort i and para-median osteotomy with pterygomaxil-lary separation seems to be an effective procedure for increasing maxillary expansion, and excessive stress side effects are lowered around the anchored teeth with the use of bone-borne devices.