Comparison of antibacterial activity of five root canal filling materials in primary dentition: an in vitro study

Introduction
Pulpectomy in primary dentition is based on chemical irrigation, mechanical debridement, and tight seal of root canal. A root canal filling material with antibacterial properties is recommended to increase chances of success.

Objective
The aim of this study was to evaluate the antibacterial activity of five root canal filling materials: zinc oxide eu-genol (ZOE), ZOE + fluoride, zinc oxide + propolis (ZOP), Endoflas^TM (ZOE + calcium hydroxide + iodoform), and Calplus (calcium hydroxide + iodoform).

Material and methods
Antibacterial efficacy against Streptococcus mutans and Enterococcus faecalis was evaluated by agar disk dif-fusion and direct contact tests at 2 hours and 24 hours. Shapiro-Wilk test was used to evaluate normality of distribution of quantitative variables. To compare zones of inhibition between groups, Kruskal-Wallis test was employed, followed by Mann-Whitney test for multiple pair-wise comparisons. To compare bacterial count within the same time point between groups, one-way ANOVA was utilized, followed by Tukey HSD post-hoc test for pair-wise comparisons (p < 0.05). Finally, to compare bacterial count within each group between the two time points (2 h and 24 h), paired t-tests were used whenever possible.

Results
ZOE, ZOP, ZOE + fluoride, and Endoflas^TM exhibited high antibacterial activity against S. mutans and complete activity against E. faecalis. Calplus showed the lowest activity against S. mutans and limited activity against E. faecalis after 2 hours, while non-existent after 24 hours.

Conclusions
Endoflas^TM seems to demonstrate optimal antibacterial properties, while adding fluoride to ZOE did not en-hance its efficacy. Propolis appears promising with similar to eugenol antibacterial properties.