Residual Antimicrobial Activity of Mtad® in Human Dentin After Obturation With Gutta-Percha/Ah26 and Resilon/ Realseal Se At Different Time Intervals; An Ex Vivo Study

Objectives: to eliminate microorganisms that are responsible for pulpal and periapical infections and to prevent reinfection of the root canal system an effective chemomechani-cal preparation by irrigants with sustained antimicrobial activity is beneficial. hereby, we evaluated the residual antibacterial activity of mtad after canal obturation at different time intervals.materials and methods: a total of 120 human single-canalled anterior teeth were se-lected. the root canals were instrumented to a standardized apical size. among all, 90 teeth received final irrigation with mtad and were divided into three groups according to their obturation materials; i.e. gutta-percha/ah26, resilon/realseal se and positive con-trols. all these groups were divided into three 1-, 3- and 6-week time interval subgroups. thirty teeth as negative control had no final irrigation with mtad, but were obturated with gutta-percha/ah26 or resilon/realsealse. dentin powder was prepared after 1, 3 and 6 weeks. dentin powder was exposed to enterococcus faecalis for 24h and then cul-tured. colony forming unit (cfu) was counted.results: residual antimicrobial activity of mtad in the teeth obturated with gutta-percha/ah26 was significantly higher than the teeth obturated with resilon/realseal se (p<0.001). it also showed a time dependent decrease in mtad antimicrobial activity for all groups. the highest antimicrobial activity of mtad was found in the 1-week positive control and 1-week gutta-percha/ah26 specimens. the lowest antimicrobial activity of mtad was found in 6-week resilon/realseal se samples and then the negative controls.conclusion: mtad had antimicrobial activity even at the sixth week, although it had a time-dependent decrease. resilon/epiphany se significantly decreased antimicrobial ac-tivity of mtad at all time points.