Time-dependent effectiveness of the intracanal medicaments used for pulp revascularization on the dislocation resistance of MTA

BACKGROUND The aim of the present study was to evaluate the time-dependent effectiveness of the intracanal medicaments used in pulp revascularization on the dislocation resistance of mineral trioxide aggregate (MTA). METHODS One hundred ninety-two extracted human maxillary incisor teeth were sectioned apically 12 mm below and coronally 2 mm above the cemento-enamel junction. Roots were enlarged to size 40 (Protaper F4). Next, Peeso reamers from #1 to #5 were used sequentially. Sodium hypochlorite (2.5 %), EDTA (17 %), and distilled water were used in final irrigation. The specimens were randomly divided into four groups (n = 48): Group 1, in which triple antibiotic paste (TAP) (ciprofloxacin + metronidazole + minocycline) was prepared and delivered into the canals using a lentulo spiral; Group 2, in which double antibiotic paste (DAP) (ciprofloxacin + metronidazole) was placed into the canals; Group 3, in which calcium hydroxide paste (CH) (calcium hydroxide + distilled water) was introduced into the roots; and Group 4 (control), in which no medicament was applied into the root canals. Then, the samples were kept in saline solution for 2, 4, and 12 weeks, after which time 16 roots were selected randomly from each group, representing the samples of each time point. After removal of the medicaments, MTA was placed into the coronal third of the roots, and the samples were incubated for 7 days. A push-out test was used to measure the dislocation resistance (DR) of MTA. The data were analyzed using a two-way ANOVA followed by Tukey's pairwise comparisons (p = 0.05). RESULTS The time factor displayed a significant effect on the DR of MTA (p < 0.05). All medicaments resulted in significantly smaller DR values after 12 weeks compared to after 1 week (p < 0.05). A significant unfavorable effect of TAP and DAP was observed as early as 2 weeks after the application, while 2 and 4 weeks after the application of CH there was no effect on the DR of MTA. No significant differences were found between the time points in the control group (p > 0.05). CONCLUSION The type and the intracanal duration of medicaments used for pulp revascularization should be chosen carefully to provide maximum antimicrobial effect while creating a favorable environment both for stem cell attachment and MTA adhesion.