완속기시(Soft-start)광조사 방식이 복합레진의 중합 및 수축응력에 미치는 효과 = EFFECT OF SOFT-START LIGHT CURING ON THE POLYMERIZATION AND THE CONTRACTION STRESS OF COMPOSITE RESIN

국문 초록 (Abstract)

본 연구에서는 기존의 할로겐 광중합기를 이용하여 40초간 조사하여 복합레진을 중합한 경우와 플라즈마 광중합기를 이용한 고강도의 중합 및 완속기시 중합 방식, 그리고 LED 광중합기를 이용한 통법의 중합과 완속기시 중합 방식으로 복합레진을 중합하여 발생되는 수축응력을 비교하고 미세경도를 측정하여 중합도를 평가하였다.
내경 7mm, 외경 10mm의 아크릴릭 주형을 제작하고 외면에 스트레인게이지를 부착 시킨 뒤 각각의 광원에 따른 중합모드로 광중합 하였다. 광조사 시점부터 1초 간격으로 600초간 수축응력을 측정하였으며, 중합 24시간 후 각 군의 미세경도를 측정하여 통계 분석하였다. 수축응력 측정 후 시편을 종단하여 주사전자현미경으로 레진수복물과 아크릴릭 주형 계면을 관찰하였다.
이상의 실험을 통해 얻은 결과는 다음과 같다.
1. 플라즈마 광과 LED 광원의 완속기시 중합방식은 각각의 기본 중합방식에 비해 중함 10분 후에 수축응력 감소를 보였다(P<0.05).
2. 완속기시 중합방식의 플라즈마 광이 가장 낮은 수축응력을 보였으나 미세경도 또한 가장 낮았다(P<0.05).
3. 완속기시 중합방식의 LED 광중합은 기존의 할로겐 광과 LED 광중합 방법에 비하여 낮은 수축응력을 보였다(P<0.05).
4. 완속기시 중하장식의 LED 광으로 조사한 시편의 미세경도는 단일광도로 조사한 할로겐 광과 LED 광중합과 비교하여 유의할만한 차이가 나타나지 않았다(P>0.05).
5. 기존의 할로겐 장과 완속기시 중합방식의 LED로 중합한 시편이 플라즈마 광과 단일강도의 LED로 조사한 군보다 더 나은 번연봉쇄를 보였다.

다국어 초록 (Multilingual 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 mold was cured using the one-step continuous curing method with three difference light sources; conventional halogen light curing for 40 seconds at 400 mw/㎠, plasma arc light curing for 6 seconds at 1300 mW/㎠ and LED light curing for 10 seconds at 700 mW/㎠. For the soft-start curing method 2 seconds light exposure at 650 mW/㎠ followed by 3 seconds at 1300 mW/㎠ and exponential increase with 5 seconds followed by 10 seconds at 700 mW/㎠ 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 micro scope(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. Micro hardness 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.

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