A Finite Element Analysis Study Comparing 3 Internal Fixation Techniques in Mandibular Sagittal Split Osteotomy

Abstract

Purpose: To analyse, and compare using finite element analysis, the biomechanical properties of the 1.7 mm miniplate fixation against 2 conventional fixation techniques (2.0 mm bi-cortical screws and 2.0 mm miniplate) used in the mandibular sagittal split osteotomy. Methods: A 3-D virtual mandible model was constructed using images from CT scan. Sagittal split osteotomy was carried out virtually, and the fixation techniques were applied onto the model. 9 virtual models consisted of the 3 fixation techniques with mandibular movements of 3 mm setback, 3 mm advancement and 7 mm advancement were developed. Bite forces of 50, 75 and 100 N were applied for incisor bite simulation and 100, 200 and 300 N for molar biting force. Finite element analysis was carried out in Solidworks, and readings of stresses and displacement were recorded. Wilcoxon rank sum test was applied and P-value of 0.05 was set for statistical analysis. Results: In this manuscript the authors have compared 3 internal fixation techniques in mandibular sagittal split osteotomy. There was a statistically significant difference for both stress and displacement readings between the 1.7 mm miniplate, the 2.0 mm bi-cortical screws and the 2.0 mm miniplate for all mandibular movements. For the 1.7 mm miniplate vs 2.0 mm bi-cortical screws, the stress reading was (P = 3.063e−08, W = 314), and for displacement was (P = 5.811e−05, W = 282). For the 1.7 mm miniplate vs 2.0 mm miniplate, the stress reading was (P = 9.862e−4, W = 263) and for displacement was (2.05e−2, W = 235). Conclusion: The 1.7 mm miniplate has adequate strength to be used in mandibular sagittal split osteotomy, although statistically less rigid when compared to the conventional 2.0 mm miniplate and 2.0 mm bi-cortical screws, especially in larger movements.

Application of Finite Element Analysis in Oral and Maxillofacial Surgery—A Literature Review

“…The selection of appropriate bridging elements is also a key determinant of successful outcomes in all orthognathic surgeries. In bilateral sagittal split osteotomy (BSSO), FEA has been eagerly used to compare the stability of bridging the bony segments with various fixation systems [ 34 , 35 , 36 , 37 , 38 , 39 ]. For this purpose, Stróżyk et al created a three-dimensional digital isotropic model divided according to the BSSO line into three segments, with 5 mm gaps in between.…”

A finite element analysis of stress distribution with various directions of intermaxillary fixation using orthodontic mini‐implants and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy

“…20,23,26 An IMF elastic force of about 150 g is applied in various directions depending on the position of the IMF screws, thus directing the vector of the IMF elastic force. 14,15,17,[20][21][22][23][24] Several finite element analysis (FEA) studies [27][28][29][30][31] have evaluated the stress distribution on the bone and fixation system according to different RIF methods after BSSRO for mandibular advancement. However, no study has investigated the stress patterns on the osteotomy and fixation sites with various directions of the IMF.…”

“…Several finite element analysis (FEA) studies 27–31 have evaluated the stress distribution on the bone and fixation system according to different RIF methods after BSSRO for mandibular advancement. However, no study has investigated the stress patterns on the osteotomy and fixation sites with various directions of the IMF.…”

Three Different Fixation Modalities following Mandibular Setback Surgery with Sagittal Split Ramus Osteotomy: A Comparative Study using Three-dimensional Finite Elements Analysis

“…Adequate skeletal stability is required to reduce postoperative problems, achieve optimal recovery, and avoid recurrence in patients following orthognathic surgery. The stabilization of the osteotomized pieces results in uncomplicated healing at the osteotomy site, a faster return to normal masticatory function, and a reduction in skeletal relapse 1 . Various fixing techniques have been proposed for osteosynthesis following a mandibular fracture or orthognathic surgery.…”

“…In vitro studies or finite element analysis (FEA) are used to assess the biomechanical stability of various fixation systems following mandibular osteotomy. The FEA is a numerical approach for solving differential equations in the fields of engineering, physics, and mathematical modeling 1 , 2 , 17 . The FEA-based research justifies its implementation in oral and maxillofacial surgery by providing advantages, such as precise analysis of stress distribution, analysis of complex mechanical systems and nonhomogeneous structures, as well as being less time-consuming and highly cost-effective 18 , 19 .…”