Antibacterial Properties of Endodontic Sealers Following Incorporation of Antimicrobial Agents

Objectives: The antimicrobial activity of different endodontic sealers following incorporation of 2% Benzalconium Chloride(BC) and 2% Cetylpirydinium Chloride(CPC)– against three different microorganism strains- was evaluated. Methods: The agar diffusion method was used for determination of the inhibitory effect of: RoekoSeal, Endomethasone, N2 and AH plus; on Streptococcus mutans - ATCC 25175, Lactobacillus casei - ATCC4646 and Actinomyces viscosus - ATCC19246. Bacterial strains were inoculated into BHIB, incubated in anaerobic atmosphere (37°C, 48 hours). From the bacteria grown in the liquid medium, the density of the inoculum was set to be equivalent to McFarland 2 standard. In Shaedler agar, 350 ìL of the bacterial suspension were equally spread. Fourty-five specimens (4x6mm) were prepared from each material without (control) and with addition of 2%BC and 2%CPC (experimental groups). All plates were incubated in anaerobic conditions (37°C). The inhibition zones were read after 48 hours (zero time), specimens were then transferred onto new plates and read after 7 days. The data were analyzed by One-Way ANOVA and Post-hoc-Tukey (HSD) test (p<0,05). Results: The effectiveness in the antimicrobial activity of the control groups, in descending order was as follows: for Streptococcus mutans- N2>Endomethasone>AH plus>RoekoSeal; for Lactobacillus casei- N2>Endomethasone=AH plus=RoekoSeal; for Actynomyces viscosus- Endomethasone=AH plus>RoekoSeal=N2. After incorporation of BC, the inhibitory effect was: for Streptococcus mutans- N2>Endomethasone>AH plus>RoekoSeal; for Lactobacillus casei- AH plus>N2>Endomethasone=RoekoSeal; for Actynomyces viscosus- AH plus>Endomethasone>RoekoSeal>N2. After incorporation of CPC the inhibitory effect was: for Streptococcus mutans- N2>Endomethasone>AH plus>RoekoSeal; for Lactobacillus casei- N2>AH plus>Endomethasone=RoekoSeal; for Actynomyces viscosus- AH plus=N2>Endomethasone>RoekoSeal Conclusions: All tested materials significantly increased their antimicrobial activity after the incorporation of antimicrobial agents. Generally, the most resistant strain was Lactobacillus casei; while CPC demonstrated better antimicrobial effect (except for RoekoSeal). The antimicrobial activity in all groups decreased after 7 days.