• Napapas Nidhidvanich, D.D.S., M.Sc.
• Panida Thanyasrisung, D.D.S., Ph.D.
• Pavena Chivatxaranukul, D.D.S., Grad. Dip. Clin. Dent., Ph.D.

Background/objectives To investigate the ability of two root canal sealers in preventing residual bacteria in dentinal tubules from accessing the main root canal space.

Materials and methods Thirty-five sterilized root samples were randomly assigned to 5 groups: Gutta percha+AH Plus sealer (AH Plus, n=10), Gutta percha+Zinc oxide eugenol sealer (ZOE, n=10), Gutta percha without sealer (GP, n=5), Flowable resin composite coating (composite, n=5), and noninfected samples+GP (aseptic control, n=5). All samples, except the aseptic control, were incubated with Enterococcus faecalis for 4 weeks. All canals were chemo-mechanically prepared and obturated according to the assigned groups. After 1 week, the filling materials, except that of the composite group, were removed and replaced with media. To investigate the presence of residual bacteria that access and regrow in the root canal space, the added-media were collected for culture and replaced with fresh media every day, up to 30 days. Data were analysed by Fisher-exact and Kruskal-Wallis test.

Results Number of samples showing residual bacteria accessing and regrowing in the canal space in AH Plus group was lower than that of the GP group (p < 0.05), while the number in the ZOE group was similar to that of the GP group (p = 0.50). However, both AH Plus and ZOE sealer significantly delayed the regrowth of residual bacteria, compared to the GP group (p < 0.001 and < 0.01, respectively).

Conclusions Although root canal sealers could not completely prevent the residual bacteria in the dentinal tubules from accessing root canal space, they possessed the ability to prevent or delay such circumstance to some extent. AH Plus was more effective than ZOE sealer in preventing the residual bacteria from accessing the root canal space.

(CU Dent J. 2016;39:53-00)