通用混合型复合树脂收缩应力的光弹分析

Determination of polymerization shrinkage stress of universal hybrid composite resins by photo-elastic stress analysis

目的:分析临床常用的3种通用混合型复合树脂Charisma、TPHSpectrum和Esthet-X收缩应力大小。方法:制备外径为80mm、厚度为4mm的光弹材料圆盘,中心制备直径为4mm的孔。分别用3种复合树脂各充填8个样本,光照固化40s。于固化后1、2、3、4、5、10、20、30min和1、24、48h记录光弹图,根据光弹图中条纹的直径计算收缩应力大小。结果:3种材料在固化后10min内收缩应力迅速增加,1h和24h时Charis-ma收缩应力最大,分别为(2.8936±0.1)MPa和(4.1904±0.1)MPa,Esthet-X最小,分别为(2.2917±0.1)MPa和(3.1439±0.3)MPa。固化后48h有79%的样本出现应力释放现象。结论:复合树脂固化后收缩应力变化速度是不同的。

Objective;To examine the polymerization shrinkage stress of three universal hybrid composite resins by photo-elastic analysis, nethod：Epoxide resin disks （d=80 mm, h=4 mm） with a cylindrical cavity （d=4 mm） in the middle were prepared. Composite resins of Charisma, TPH Spectrum and Esthet-X were respectively filled in the cavities for the formation of specimens. Eight specimens were made for each resin. The resin specimens were light cured for 40 s by Dentsply QHL75 Curing lite. Polymerization contraction stress was calculated based on the diameter of the isochromatic rings of first order obtained from the diameter of epoxide resin specimen at 1,2,3,4,5,10,20 and 30 min, 1,24 and 48 h after curing. The statistical analysis was carried out with the Wilcoxon test. Results：Polymerization contraction stress rised rapidly in the first 10 min after curing. 1 and 24 h after curing the shrinkage stress （MPa） of Charisma were 2. 893 6 ±0.1 and 4. 190 4 ±0.1 ,while that of Esthet-X were 2. 291 7 ±0.1 and 3. 143 9 ± 0.3, respectively. The shrinkage stress values of TPH spectrum was between those of Charisma and Esthet-X 24 h after curing. 79% specimens showed shrinkage stress releasing during 24 and 48 h after curing. Conclusion：The rates of the shrinkage stress of the three studied resin composites are different.