LED와 플라즈마 광원의 완속기시 광중합 방식이 복합레진의 수축응력에 미치는 영향

Abstract

The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin (Filtek Z-250, 3M ESPE, USA) was cured using the one-step continuous curing method with three difference light sources ; conventional halogen light (XL3000,3M ESPE, USA) cure for 40 seconds at 400 mw/㎠, LED light (Elipar Freelight 2, 3M-ESPE, USA) cure for 20 seconds at 800 mW/㎠ a and plasma arc light (Flipo, LOKKI, France) cure for 12 seconds at 1300 mW/㎠. For the soft-start curing method ; LED light (Elipar Freelight 2, 3M-ESPE, USA) cure exponential increase with 5 seconds followed by 17 seconds at 700 mW/㎠ and plasma arc light (Flipo, LOKKI, France) cure 2 seconds light exposure at 650 mW/㎠ followed by 11 seconds at 1300 mW/㎠ The strain guage method was used for determination of polymerization contraction. Measurements were recorded at each 2 second for the total of 800 seconds including the periods of light application. Obtained data were analyzed statically using Repeated measures ANOVA, One way ANOVA, and Tukey test. The results of present study can be summarized as follows: 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05). 2. LED and Plasma Light curing with soft-start showed lower contraction stress than the one-step continuous light curing (P<0.05). 3. Contraction stress in LED and Plasma curing light groups were higher than Halogen curing light groups, but they were not revealed significant difference.(p>0.05)