การวิเคราะห์ตัวแปรต่อการกระจายความเค้นในบริเวณ โดยรอบกระดูกเพดานปากและในสกรูอิมแพลนท์

Abstract

The purpose of this study was to investigate the effect of three parameters on mini-screw and palatal bone in terms of stress distributions by using finite element method (FEM). The parameters studied were length of mini-screw, size of diameter and number of screw (1 and 2). In this present study was carried out by constructing 3D models of mini-screw and palatal bone, running simulation under boundary conditions in order to get results (stress distribution). Results from finite element program would be compared to experimental models and also with mathematical equations relying on beam theory. From comparing result of these 2 methods, it showed that both methods were conformed to each other. Once results were agreed, varying length of screw, size of diameter and numbers of screw were applied. Lengths of screw varied from 6 to 12 millimeters. Diameters of screw varied from 1 to 2 millimeters. Numbers of screw were 1 and 2. Results showed that maximum stress distributions in palatal bone was 7.679 MPa found in screw length of 6 mm. diameter 1 mm. and the minimum stress distributions was 0.174 MPa found in screw length of 12 mm. diameter 2 mm. From mathematic equations showed that diameter reverses variation with stress distributions so as the length of increasing would affect stress distribution in palatal bone decreased. And studies showed that maximum stress distributions in palatal bone were found in case single screw (34.81 MPa). Nevertheless, factor of safety has to be applied to analyze palatal bone failure. Factor of safety in maximum stress distributions were calculated under Coulomb’s Mohr Theory equal to 17.50, this number tells us that 2 newton forces wouldn’t make palate bone cracked.