The Relationship Between Antibacterial And Smear Layer Removal Efficacy Of Different Irrigation Solutions

ObjectivesThe objective of this study was to comparison the effect of smear layer and antimicrobial activity and the residual antimicrobial activity of QMix, MTAD, CTR, CHX, EDTA and distilled water, and analysis the relationship between antibacterial and residual antimicrobial activity and smear layer removal efficacy of different irrigation solutions.MethodsOne hundred and seventy single-rooted, non-carious maxillary anterior teeth were made from standard model, after high temperature and high pressure the samples were infected with Enterococcus faecalis. The root canals were prepared with the Crown-Down technique, after preparing the canal chemomechanically, final irrigation were performed with QMix, MTAD, CTR, CHX, EDTA, distilled water and non-irrigation(control group), then each group was divide into two subgroups, one of the subgroups was to evaluate the smear layer removal efficacy in coronal, middle and apical thirds. Sampling, cultivation, observe and record the uninfected samples were performed in the other subgroup in immediately, first, second, third....day, to evaluate the antibacterial and residual antimicrobial activity of the six irrigation solutions in coronal, middle and apical thirds. And analysis the relationship between antibacterial and residual antimicrobial activity and smear layer removal efficacy of the six irrigation solutions. For statistical analysis one-way ANOVA was used to evaluate the efficacy of smear layer of different irrigation, chi-square test was used to evaluate the antibacterial and residual antimicrobial activity. All statistical analyses were performed by means of SPSS17.0software.ResultsSmear layer removal results showed:there was significant difference comparing QMix, MTAD, EDTA with the control group (P<0.05), the scores of smear layer were all lower than control group. When pairwise comparison, there were significant difference between each group (P<0.05), except the comparing between QMix and MTAD, and between CTR, CHX, distilled water, control group(P>0.05). The scores of smear layer from low to high was:EDTA> QMix/MTAD> CTR/CHX/distilled water/control group. In each group, the crown third scores of smear layer was lowest, and the apical third was most high, and there was significant difference between them (P<0.05)Antimicrobial results showed: there was significant difference between QMix, MTAD, CTR, CHX and control group when pairwise comparison (P<0.002)Residual antimicrobial results showed:only in first, second and third day, when pairwise comparison there were significant difference between EDTA, distilled water, control group and QMix, MTAD, CTR, CHX (P<0.002)There was no relevance between antibacterial and residual antimicrobial activity and smear layer removal efficacy of the six irrigation solutions.ConclusionsQMix, MTAD, EDTA could removal the smear layer efficacy, but can not completely. EDTA was the best on smear layer removal, follow by QMix and MTAD. CTR, CHX and distilled water can not remove smear layer.QMix, MTAD, CTR, CHX had antimicrobial, but can not killed the Enterococcus faecalis completely. As the final irrigation the efficacy of antimicrobial activity of them was similarity.QMix, MTAD, CTR, CHX had residual antimicrobial, but the last time was different. The last time of residual antimicrobial was as followed: MTAD> CTR> QMix> CHX.There was no relevance between antibacterial and residual antimicrobial activity and smear layer removal efficacy of the six irrigation solutions.In conclusion, EDTA was most effectively in smear layer removal. QMix and MTAD not only can remove smear layer but also have favorable antimicrobial residual antimicrobial activity. CTR and CHX can not remove smear layer but have favorable antimicrobial and residual antimicrobial activity. Distilled water can not remove smear layer and has not antimicrobial and residual antimicrobial activity.