| EFFECT OF SOFT-START LIGHT CURING ON THE POLYMERIZATION AND THE CONTRACTION STRESS OF COMPOSITE RESIN |
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| 완속기시(Soft-start) 광조사 방식이 복합레진의 중합 및 수축응력에 미치는 효과 |
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위유민, 오유향, 이난영, 이창섭, 이상호 |
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조선대학교 치과대학 소아치과학교실 |
Correspondence:
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| Abstract |
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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 mold was cured using the one-step continuous curing method with three difference light sources; conventional halogen light curing for 40 seconds at 400mw/cm^2, plasma arc light curing for 6 seconds at 1300mW/cm2 and LED light curing for 10 seconds at $7The purpose of this study was to evaluate the influence of soft-start light curing on contraction stress and hardness of composite resin. Composite resin mold was cured using the one-step continuous curing method with three difference light sources; conventional halogen light curing for 40 seconds at . For the soft-start curing method ; 2 seconds light exposure at 650\;mW/cm2 followed by 3 seconds at 1300mW/cm2 and exponential increase with 5 seconds followed by 10 seconds at 700mW/cm2 were used. Contraction stress was measured using strain gauge method and Vickers hardness was measured 24 hours after polymerization at the top and bottom of specimens. Resin-acrylic interfaces were observed using a scanning electron microscope(SEM). The results of present study can be summarized as follows: 1. Contraction stresses at 10 min after polymerization were significantly reduced with the soft-start curing both in plasma and LED light sources(P<0.05). 2. Plasma light curing with soft-start resulted in not only the lowest contraction stress, but also the lowest hardness(P<0.05) 3. LED light curing with soft-start showed lower contraction stress than the one-step continuous halogen and LED light curing(P<0.05). 4. Microhardness of specimens cured by LED light with soft-start was equivalent to that of cured by the one-step continuous halogen and LED light(P>0.05). 5. Curing by LED light with soft-start and conventional halogen light resulted in better marginal sealing than plasma light and one-step LED light curing. |
| Key Words:
Soft-start light curing, Contraction stress, Microhardness |
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