The effect of medicaments used in endodontic regeneration on root fracture and microhardness of radicular dentine.

AIM: To investigate the effect of medicaments used in endodontic regeneration on root fracture resistance and microhardness of radicular dentine. METHODOLOGY: The root canals of mandibular premolars (n = 180) were instrumented and randomized into three treatment groups and an untreated control group. Each treatment group received either triple antibiotic paste (TAP), double antibiotic paste (DAP) or calcium hydroxide paste [Ca(OH)(2)] intracanal medicament. Teeth were kept in saline for 1 week, 1 month or 3 months. After each time-point, 15 teeth were randomly selected from each group and two root cylinders were obtained from each tooth. One cylinder was subjected to a fracture resistance test, and the other cylinder was used for a microhardness test. Two-way ANOVA and Tukey's pairwise comparisons were used for statistical analysis. RESULTS: For the microhardness test, the two-way interaction between group and time was significant (P < 0.001). The intracanal application of TAP and DAP caused significant and continuous decrease in root dentine microhardness after one (P < 0.05) and 3 months (P < 0.001), respectively. The three-month intracanal application of Ca(OH)(2) significantly increased the microhardness of root dentine (P < 0.05). The time factor had a significant effect on fracture resistance (P < 0.001). The three intracanal medicaments caused significant decreases in fracture resistance ranging between 19% and 30% after 3-month application compared to 1-week application. CONCLUSION: In this laboratory study, the 3-month application of triple antibiotic paste, double antibiotic paste or calcium hydroxide paste medicaments significantly reduced the root fracture resistance of extracted teeth compared to a 1-week application.