복합 레진의 간헐적 광중합 방법이 중합 수축 속도와 치아의 교두 변위에 미치는 영향 = EFFECT OF INTERMITTENT POLYMERIZATION ON THE RATE OF POLYMERIZATION SHRINKAGE AND CUSPAL DEFLECTION IN COMPOSITE RESIN

국문 초록 (Abstract)

지금까지 다수의 연구자들에 의해 광중합형 복합 레진을 중합하는 방법에 있어서 광조사 강도,시간을 조절하여 중합 수축의 속도를 감소시키기 위한 시도가 있었으나, 간헐적 중합법에 관한 구체적인 연구가 부족하다. 이에 저자는 광중합 복합 레진을 간헐적으로 광중합시켜 기존의 연속 중합법과 비교하여 중합 수축의 속도를 측정하고 교두 변위에 대한 영향을 평가해 보고자 하였다.
실험에 사용된 수복 재료는 2종의 광중합형 복합 레진으로 Heliomolar와 Pyramid이며 , 중합 수축량을 측정하기 위해 자체 제작한 Linometer (R&B Inc., Daejon, Korea)을 사용하였고 광중합시 광조사 차단장치를 시편과 Linometer 사이에 위치시켜 각각의 서로 다른 중합 주기; (1) 연속 광중합 (60초간 계속 광조사); (2) 2초 광조사, 1초 광차단 (90초 시행); (3) 1초 광조사, 1초 광차단 (120초 시행); (4) 1초 광조사, 2초 광차단 (180초 시행)로 중합시켰다. 군 별로 조사된 총에너지량이 동일하도록 중합 시간을 조절하였고, 최종 중합 수축량을 측정하였으며 중합 수축의 최고속도 (R_(max))와 최고속도를 나타낸 peak time (PT)을 계산하였다.
교두 변위의 측정을 위해서는 각 군별로 10개의 건전한 상악 소구치에 변형시킨 제2급 와동을 형성한 다음 상아질 접착제를 도포하고 일정량의 복합 레진을 충전한 후 치아를 자체 제작된 치아 변위 측정기 (R&B Inc., Daejon, Korea)에 위치시켜 교두 변위양을 알아보았다. 통계분석은 ANOVA test를 이용하여 군 간의 비교를 하였고, 재료간의 비교를 위해서는 t-test를 시행하였다.
실험 결과는 1) 선수축량은 군 간에 차이가 없었고 (p> 0.05), Pyramid가 Heliomolar보다 중합 수축량이 컸다 (p < 0.05). Peak time은 Heliomolar와 Pyramid 레진 모두에서 간헐적 광중합시 더 늦게 나타났다. R_(max)는 Heliomolar는 4군 < 3군, 2군 < 1군 순이었고, pyramid는 3군 < 4군 < 2군, 1군 순으로 측정되었다. 2) Heliomolar는 4군 < 3군 < 2,1군 그리고 pyramid는 4,3군 < 2, 1군 순으로 교두 변위가 컸으며 (p < 0.05), pyramid가 Heliomolar보다 교두 변위가 크게 나타났다 (p<0.05).
이번 실험을 통해 복합 레진을 광조사 차단장치를 이용하여 간헐적 광중합 시켜 중합 수축속도를 늦춤으로써 교두 변위 양이 감소됨을 알 수 있었다.

다국어 초록 (Multilingual Abstract)

This study investigated the effect of intermittent polymerization on the rate of polymerization shrinkage and cuspal deflection in composite resins.
The linear polymerization shrinkage of each composite was measured using the custom-made linometer along with the light shutter specially devised to block the light at the previously determined interval. Samples were divided into 4 groups by light curing method; Group 1) continuous light (60s with light on); Group 2) intermittent light (cycles of 3s with 2s light on & Is with light off for 90s); Group 3) intermittent light (cycles of 2s with Is light on & Is with light off for 120s); Group 4) intermittent light (cycles of 3s with Is light on & 2s with light off for 180s). The amount of linear polymerization shrinkage was measured and its maximum rate (Rmax) and peak time (PT) in the first 15 seconds were calculated. For the measurement of cuspal deflection of teeth, MOD cavities were prepared in 10 extracted maxillary premolars. Reduction in the intercuspal distance was measured by the custom-made cuspal deflection measuring machine. ANOVA analysis was used for the comparison of the light curing groups and t-test was used to determine significant difference between the composite resins.
pyramid showed the greater amount of polymerization shrinkage than Heliomolar (p < 0.05). There was no significant difference in the linear polymerization shrinkage among the groups. The Rmax was group 4 < 3, 2 1 in Heliomolar and group 3 < 4 < 2, 1 in Pyramid (p < 0.05). Pyramid demonstrated greater cuspal deflection than Heliomolar. The cuspal deflection in Heliomolar was group 4 < 3 < 2, 1 and group 4, 3 < 2, 1 in Pyramid (p < 0.05).
It was concluded that the reduced rate of polymerization shrinkage by intermittent polymerization can help to decrease the cuspal deflection.

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