Relevance of Resin for Photoelasticity

The goal of this study is to test photoelastic resins for manufacturing models with teeth and/or implants under chewing load. Four commercial brands have been chosen: Araldite (Ciba Chemicals), Flexible GIV-Rigid GIV (Polipox) and PL2 (Measurements Group). Nine discs were manufactured, four of them from each of the photoelastic resin brands and five from different proportions of mixture between Flexible GIV and Rigid GIV. All the models were subjected to the diametral compression test, and observed in a circular polariscope. The first order fringe has always been adopted as a benchmark to calculate the photoelastic constant. To the load of interest (150 Newtons), Flexible GIV resin showed areas that followed the elastic regime. Residual stresses for the resin PL2 and persistence of bubbles within the model were observed. Rigid GIV Resin generated the first fringe order only at 280 Newtons load. Araldite resin behaved within the elastic regime and there were no areas with excessive concentration of fringes. The models generated from the manual mixing generated non-homogeneous photoelastic images. The Araldite resin showed to be the most suitable material for manufacturing birefringent models with teeth and/or implants under chewing load.本研究旨在测试适用于制作带有牙齿和/或种植体的咀嚼载荷模型的光弹性树脂（photoelastic resin）。本次研究选取了四款商用品牌的光弹性树脂：Araldite（来自Ciba Chemicals）、Flexible GIV-Rigid GIV（来自Polipox）以及PL2（来自Measurements Group）。共制备九片圆盘试样：其中三款品牌树脂各制备四片，剩余五片由Flexible GIV与Rigid GIV按不同比例混合制得。所有试样均开展径向压缩试验，并通过圆偏振光弹性仪进行观测。研究始终以一级条纹作为基准，用以计算光弹性常数。在目标载荷150牛顿时，Flexible GIV树脂的部分区域呈现弹性力学行为。观测到PL2树脂存在残余应力，且其制备的模型内部存在气泡残留。Rigid GIV树脂仅在载荷达到280牛顿时，才会产生一级条纹。Araldite树脂全程呈现弹性力学行为，未出现条纹过度集中的区域。手工混合制备的模型，其光弹性图像呈现不均匀分布。研究结果表明，Araldite树脂是最适用于制备带有牙齿和/或种植体的咀嚼载荷双折射模型的材料。