[Use of digital image correlation method to measure polymerization shrinkage dynamics of light cured composite resin].

作者：Dan-ping Ruan, Chunyun Wu, Dinghua Zhang · 发表于：PubMed · 年份：2012 · 研究领域：Dental materials and restorations、Anatomy and Medical Technology、Optical measurement and interference techniques

PURPOSE: To evaluate the role of digital image correlation method in measuring the initiation and propagation of polymerization shrinkage of light cured composite resin. METHODS: Six freshly extracted complete molars were collected and divided into 2 groups randomly. The proximal surface was sliced to plane and proximal-occlusal cavity were prepared with 2.0 mm×2.0 mm×2.0 mm in size, then the tissue surface was treated with etch and bond. The cavity samples in the first group were filled with 3M Z350, and the samples in the second group were filled with material 3M Valux Plus, the proximal surfaces were dealt with random speckle, then fixed to micro tensile framework. As light curing proceeded for 40 seconds, all the speckled images were collected by digital camera in real-time simultaneously. The digital image correlation analysis software was used to deal these images and achieve the displacement and strains in both horizontal and vertical direction on all pixel points, at last the linear shrinkage ratios were counted and the displacement at free surface of the two materials at the 20th second were analyzed with SPSS 12.01 software package for Student's t test. RESULTS: The results showed displacement and strain distribution were accurately achieved and their correlation ratios (R) were bigger than 0.98. The shrinkage represented anisotropy with different direction and unequal value in 40 seconds. The linear shrinkage values of the two materials were 0.439%-0.75%, 0.526%-0....