chlorhexidine이 MTA의 간접인장강도에 미치는 영향

Abstract

MTA(Mineral Trioxide Aggregate)(ProRoot MTA,Dentsply, Tulsa dental, Tulsa, OK, USA)는 Torabinejad 등에 의해 1993년 소개된 이후 치근단 천공 치료재와 치수복조제, 치근단 충전재로서 주목받았고 널리 사용되고 있다. 한편, Chlorhexidine(CHX)은 1960년대 초 근관 세척액으로 소개된 이래 오랜 기간 근관 세척액과 근관 내 약제로서 사용되어 온 물질로서 in vitro 실험에서 Enterococcus faecalis에 대한 항균효과가 있음이 인정되고 있다. 최근의 여러 가지 실험을 통해 chlorhexidine과 MTA를 혼합하여 사용하였을 때 항균성이 증가하고 경화시간을 단축시키는 장점이 있음이 밝혀졌다. 본 연구는 chlorhexidine이 MTA의 압축강도에 미치는 영향에 대한 연구의 후속 연구로써, 항균효과를 유지하고 경화시간을 단축하고 임상적으로 사용가능한 chlorhexidine의 농도범위에서 간접인장강도를 측정해봄으로써 임상적으로 사용할 때 큰 문제점이 없는지 검토해보기 위해 시행되었다.

MTA(ProRoot MTA, Dentsply, Tulasdental, OK, USA)를 멸균 증류수, 1.0 % CHX, 0.5 % CHX과 혼합하여 3가지 군을 만들었다. 시편을 제작할 때에는 제조사의 지시에 따라 w/p ratio 0.33으로 혼합했고 모든 입자가 용액에 충분히 섞일 때까지 1분간 혼합했다. 혼합물은 amalgam plugger를 이용하여 직경 6 0.05069 mm, 높이 4 0.0727 mm의 Teflon 원통형 mold내에 2분 내에 응축했다. 시편이 담긴 mold를 상대습도 100 %의 culture incubator에 보관한다. 24시간 후 거즈를 제거하고 추가로 48시간 동안 incubator안에서 총 72시간동안 경화시켜 시편을 만들었다. 만들어진 시편은 LF-Plus digital testing machine (Lloyd instrument, Ametek)을 이용해 1 mm/min의 속도로 압력을 가하여 시편이 파절될 때의 load를 측정했다. SPSS ver. 12.0K를 이용하여 one way ANOVA와 Duncan의 사후검정으로 통계적인 차이점에 대해 분석했다.

실험 결과 1 % CHX, 0.5 % CHX과 혼합한 경우가 증류수와 섞은 실험군에 비해서 간접인장강도가 감소했고 1 %의 chlorhexidine과 혼합한 경우의 간접인장강도가 가장 작았다. 통계 분석 결과 증류수와 혼합을 했을 때와 chlorhexidine 용액과 혼합했을 때가 유의할만한 차이가 있었다.(p < 0.05)

주요어: mineral tionxide aggregate, chlorhexidine, 간접인장강도 학번: 2008-22066

MTA(Mineral Trioxide Aggregate) (ProRoot MTY, Dentsply, Tulsa dental, Tulsa, OK, USA) had received attention and been used widely in root perforation repair treatment, pulp capping agents, and root-end filling materials, since it was first introduced in 1993 by Torabinejad et al. It can be used as root-end filling materials, having several ideal properties. Meanwhile, Chlorhexidine(CHX) was used as a root canal cleansing solution and intracanal medication for a long time, ever since it was introduced in early 1960s; it is also acknowledged to have antimicrobial effect on E. faecalis through in vitro experiment. From several recent experiments, using the mixture of Chlorhexidine and MTA was found to have an advantage in increasing the antimicrobial effect and shortening the curing time. However, if using the mixture of two substances causes a problem in strength, it would be restricted in clinical usage. This year, combining MTA with 1% of Chlorhexidine solution was proved to have no serious problem in compressive strength. This experiment is a follow-up experiment on the effect of Chlorhexidine on the compressive strength of MTA; conducted to examine whether the clinical use of Chlorhexidine has no serous problem, by measuring the diametral tensile strength within the range of the concentration of Chlorhexidine in which the antimicrobial effect is maintained, curing time is shortened and clinical usage is possible.

The MTA (ProRoot MTA, Dentsply, Tulasdental,Tulsa, OK, USA) in the experiment was mixed with three groups; sterile distilled water, 1.0% Chlorhexidine solution - which concentration is known to have the best antimicrobial effect - and 0.5% Chlorhexidine solution. In making the specimen, it was mixed in w/p ratio of 0.33 for 1 minute, for all particles to be fully blend with the solution. The diametral tensile strength was measured following ISO 9917-1 dental water based cement. The mixture was condensed in a Teflon cylindrical mold - 6mm in diameter and 4mm in height (height/diameter 0.67) - for 2 minutes. The mold with the specimen was kept in the culture incubator with the relative humanity of 100%. After 24 hours, the gauze was removed, and the specimen was hardened for 48 hours more; the specimen was made by hardening for 72 hours in total. The load of the specimen when it fractured was measured by using LF-Plus digital testing machine(Lloyd instrument, Ametek) with the speed of 1mm per minute. By SPSS for window 12.0K, the data was analyzed using one way ANOVA and Duncan's post hoc test. Each group was analyzed and P-value of less than 0.05 was considered to have statistical significance.

As a result, group 1, 2 had decreased diametral tensile strength compared to case-control of mixture with sterile distilled water, and the mixture with 1% Chlorhexidine had a lesser diametral tensile strength than the other. Statistical analysis showed that mixing with sterile distilled water and mixing with Chlorhexidine had a significant statistical difference. (p < 0.05)

Key words: mineral trioxide aggregate, chlorhexidine, diametral tensile strength Student number: 2008-22066