Deformation Assessment of the Manually Pre-Bent Titanium Miniplates in Orthognathic Surgery With Finite Element Analysis

Abstract

This study summarized the literature regarding the application of pre-bent titanium miniplates in orthognathic surgery and evaluated the extra deformation of the manually pre-bent titanium miniplates via finite element analysis for acquiring higher surgical accuracy. The literature was reviewed with a chart. Three models of titanium miniplates with different thicknesses (1.0 mm, 0.8 mm, 0.6 mm) were created using COMSOL Multiphysics software for biomechanical behavior analysis. The 3 models were virtually bent into 5 angles (15 degree, 30 degree, 45 degree, 60 degree, 80 degree). respectively to simulate the preoperative virtual bending, then to simulate the practical manual bending via finite element analysis. The stresses and displacements of these models were recorded. The models from virtual bending simulation and manual bending simulation were registered to analyze the deviations. The results showed that the maximum stress and the displacement deviations between the virtual bending models and the manual bending models increased with the thickness and bending angle of the pre-bent miniplate models. To improve the surgical accuracy, measures should be applied to the manually pre-bent titanium miniplates to reduce the extra deformation when the plate being thicker and the bending angle being larger.

A Novel Orthognathic Surgery With a Half-Millimeter Accuracy for the Maxillary Positioning Using Prebent Plates and Computer-Aided Design and Manufacturing Osteotomy Guide

“…The other cause of maxillary repositioning error other than the surgical technique in the prebend plate scanned guide procedure is an extra deformation of titanium miniplates after scanning caused by the release of the residual stress of titanium in the process of manual prebending. 11,12 In particular, the residual stress increases when the number of the banding angle of the plates increases. 12 During preoperative preparation, the plates may be bent several times to fit well to the surfaces of the planned maxillary model, resulting in plate deformation.…”

“…11,12 In particular, the residual stress increases when the number of the banding angle of the plates increases. 12 During preoperative preparation, the plates may be bent several times to fit well to the surfaces of the planned maxillary model, resulting in plate deformation. In addition, the manually prebend plates were more fragile because of microfractures, and fragile points caused by manual bending, which decreased their resistance.…”

Evaluation of the Properties of 3D-Printed Ti Alloy Plates: In Vivo and In Vitro Comparative Experimental Study

“…Loukota and Shelton reported that more than five times bending the plates would reduce the rigidity of the flexion part [ 6 ]. The greater the Ti plate bending range, the greater its maximum stress, which would deviate more from the design scheme [ 7 ]. Obtaining the perfect shape and attachment of the Ti alloy plates is still a vital issue in oral and maxillofacial surgery.…”