물 흡수에 따른 fiber reinforced composite(FibreKor？？)의 굽힘 특성 변화 = Flexural characteristic changes of fiber reinforced composite (FireKor？？) according to water absorption

국문 초록 (Abstract)

보철이나 수복 영역에서 재료 자체의 기계적 특성을 강화하기 위해 많이 사용되어 오던 fiber reinforced composite (FRC)는 최근 교정 영역까지 그 사용이 확대되고 있다. 이 연구의 목적은 silica glass fiber로 강화된 FRC (FibreKor®, Jeneric/Pentron Inc., Wallingford. U.S.A.)를 다양한 기간 동안 물에 저장하였을 때 물 흡수가 FRC의 굽힘 특성에 미치는 영향을 알아보고자 함이었다. 시편은 임상에서 적용하는 원형, (직사)각형의 두 가지 형태를 기준으로 plasma arc light를 이용하여 광중합하여 제작하였다. 각형, 원형 각각 5개의 시편을 실온(평균 23°C)의 증류수 안에 0시간, 1시간, 1일, 1주, 15일, 1개월, 3개월의 기간 동아 보관한 후 torque tester를 이용하여 굽힘 시험을 시행하였다. 굽힘 강성(flexural stiffness)은 24시간 후에 원형의 경우 59%, 각형의 경우 25%로 감소했으며 3개월 후에는 각각 29%, 19%의 실험 전 상태의 강성을 나타냈다. 항복 굽힘 모멘트(yield flexural moment, 3°C offset)는 24시간 후에 원형의 경우 45%, 각형의 경우 76%로 감소했으며 3개월 후에는 실험 전 항복 굽힘 모멘트의 29%, 60%로 각각 감소하였다. 파절 굽힘 모멘트 (ultimate flexural moment)는 24시간 후에 원형의 경우 36%, 각형의 경우 76%로 감소했으며 3개월 후에는 실험 전 값의 25%, 37%로 각각 감소하였다. 이상의 실험을 통하여 FibreKor®눈 물에 보관 시 초기에 굽힘 강성이 급격히 저하됨을 알 수 있었다. 따라서 수분에 대한 굽힘 강도 증가를 위한 연구가 향후 필요할 것이다.

다국어 초록 (Multilingual Abstract)

Fiber reinforced composite (FRC) has been widely used in operative and prosthetic fields of dentistry and its use is expanding into the orthodontic field. The purpose of this study was to examine the changes of flexural properties of FRC reinforced with silica glass fiber (FibreKor?,Jeneric/Pentron Inc., Wailingford.U.S.A.) according to the duration of water absorption. Specimens were grouped according to their shape as round and rectangular cross sections. and were immersed in distilled water at room temperature (23°C) for 0 hour, 1hour, 1 week. 15 days. 1 month and 3 months. The number of specimens was 5 for each duration and bending test was done using a torque tester. The flexural stiffness after 24 hour water immersion was reduced to 59% for round specimens and 25% for rectangular specimens and after 3 months of water immersion it was reduced to 29% and 19% stiffness of the 0 hour-specimen respectively. Yield flexural moment after 24 hour water immersion was reduced to 45% for round specimens and 76% for rectangular specimens and after 3months of water immersion it was reduced to 29% and 60% stiffness of the 0 hour-specimen respectively. Ultimate flexural moment after 24 hour water immersion was reduced to 36% for round specimens and 76% for rectangular specimens and after 3 months of water immersion it was reduced to 25% and 37% stiffness of 0 hour-specimen respectively. Those results suggested that the flexural stiffness of FibreKor? decreased greatly after initial water immersion. Consequently. further research for the maintenance of strength against water will be necessary.

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