Changes in µ-TBS to pulp chamber dentin after the application of NaOCl & reversal effect by using sodium ascorbate

Abstract

Clinical suggestion for the limitation of application time of NaOCl solution is needed to avoid large reductions in resin-dentin bond strength. The aim of this study was to measure the change of μ -tensile bond strength after the various application time of 5.25% NaOCl solution to pulp chamber dentin in endodontic access cavity, and to evaluate the effect of 10% sodium ascorbate application for 10 min on bond strength after the treatment of 5.25% NaOCl solution. In this experiment, there were no statistical differences(p>0.05) in bond strengths between upper chamber dentin and lower chamber dentin. NaOCltreated group for 20 min did not show any significant decrease(p>0.05) in bond strength than non-treated control group. In contrast to that, bond strengths of NaOCl-treated groups for 40 & 80 min were significantly lower(p<0.05) than that of non-treated control group. 10% sodium ascorbate retreated group for 10 min after 5.25% NaOCl application for 40 min to chamber dentin showed the recovery of bond strength significantly. However, the bond strength of sodium ascorbate retreated group after 5.25% NaOCl application for 80 min was still significantly lower(p<0.05) compared to the non-treated control group, which means the reductions in resin-dentin bond strength were not fully reversed. On the contrary, sodium ascorbate retreated group after 5.25% NaOCl application for 5 min showed significantly higher(p<0.05) bond strength compared to the control group, which demonstrates its superior recovery effect. In SEM exminations of specimens retreated with 10% sodium ascorbate after NaOCl application for 40 & 80 min showed that resin tags were formed clearly and densely, but weakly in density and homogeneity of individual resin tag compared to the control specimen. [J Kor Acad Cons Dent 34(5): [515][516][517][518][519][520][521][522][523][524][525] 2009]

Influence of Sodium Hypochorite & EDTA on the Microtensile Bond Strength of Ethanol Wet Bonding

“…그리고 이 러한 사실은 접착제가 더욱 더 친수성이 되어가 는 것에 대한 우려를 증가시켰다 21) . 최근 연구들 , 다른 일부 연구에서는 40분 이상을 적용 시킨 후에야 결합강도에 유의한 감소가 나타난 다고 하였다 3,26) . 이를 볼 때 상아질의 결합강도 에 대한 NaOCl의 영향은 적용 시간에 어느 정도 영향을 받는 것으로 생각된다.…”