Curing method for reducing polymerization contraction stress of light-curing resin composite

光固化树脂复合材料因其美观、使用方便、与牙齿结构粘结良好、力学性能改善等优点，现已广泛应用于临床。然而，光固化树脂复合材料通常是从靠近光源的树脂表面聚合而成，这会导致树脂复合材料的聚合收缩朝向光线。这种收缩在树脂和洞壁/底板之间产生了比自固化树脂复合材料更大的间隙。本项目旨在评价轻拧法边缘封闭和洞壁适合性对不同C因子形状的树脂复合体修复的影响，以及增量填充技术对I类牙本质洞底板树脂微粘结强度的影响。此外，对两种光固化方法的树脂-牙界面进行了环境扫描电子显微镜观察，结果表明，渐进式充填技术并没有提高牙本质与窝洞底的微粘结强度。慢启动固化法：2 70 mW/cm2 10 S+5 S(区间)+6 0 0 mW/cm2 5 0 S降低了聚合收缩应力，无论粘接体系和C因子如何，都有改善边缘密封性和树脂复合材料与洞壁适配性的趋势。常规固化方法：600 mW/cm~2 60时，S粘固剂边缘密封性和管壁适合性较差。环境扫描电子显微镜观察表明，慢启动固化法提高了树脂复合材料与洞壁的适合性，对有釉质边缘和无牙釉质边缘的洞均有效。

Light-cured resin composites are now widely used in daily clinical practice because of their esthetic advantages, ease of use, good bonding to tooth structure, and improved mechanical properties. However, light-cured resin composites are usually polymerized from the resin surface near a light source, which causes polymerization contraction of the resin composite towards the light. This shrinkage creates more gaps between the resin and cavity wall/floor than self-cured resin composites.This projects was to evaluate the effect of the light wring method on the marginal sealing and cavity wall adaptation on resin composite restorations with different C-factor shapes and also to evaluate the effect of incremental filling technique on resin micro-bond strength to Class I dentin-cavity floors. Moreover, environmental SEM observation was carried out to evaluate on resin-tooth interface using two light curing method.It was concluded that incremental filling technique did not improve dentin micro-bond strength to cavity floor. On the other hand, slow-start curing method ; 270 mW/cm^2 10 s + 5 s (interval) + 600 mW/cm^2 50 s reduce the polymerization contraction stress, and tended to improve marginal sealing and resin composite adaptation to the cavity wall regardless of bonding system and C-factor. Ordinary curing method ; 600 mW/cm^2 60 s resulted in poor marginal sealing and wall adaptation. Environmental SEM observation showed that the slow-start curing method improved resin composite adaptation to the cavity wall and this curing method was effective to the cavities both with and without enamel margin.