Influence of different types of intracanal medicament and root canal sealers on root dentin fracture resistance at two different time intervals

The aim of this study was to investigate the influence of different types of intracanal medicaments (Ultracal XS, Bio-C Temp) and root canal sealers (AH Plus, Bio-C Sealer) on root dentin fracture resistance at different time intervals. One hundred seventy single-root human mandibular premolar teeth used. Samples were divided into three main groups: negative control (unprepared and unfilled, n=10), positive control (prepared but unfilled, n=10), and experimental groups (10 groups, n=15). The root canals in the experimental groups and positive group were prepared chemomechanically. The single-visit groups without medicament were obturated with either AH Plus or Bio-C Sealer. In the medicament-applied groups, Ultracal XS or Bio-C Temp was applied to the root canals for 1 week or 1 month, followed by root canal filling with AH Plus or Bio-C Sealer. Fracture resistance of all samples was measured using a universal testing machine under vertical loading. Additionally, the sealer-dentine junction areas of the experimental groups were examined using SEM, including EDX analysis. Data were analyzed using One-way ANOVA and post hoc Tukey HSD tests. Fracture resistance was highest in the negative control and lowest in the positive control. Single-visit obturation without medicament demonstrated significantly higher fracture resistance compared to the medicament-applied groups. No significant differences were found the single-visit AH Plus and Bio-C Sealer without medicament. Similarly, no significant difference was observed between the groups obturated with AH Plus or Bio-C Sealer after application of Ultracal XS or Bio-C Temp. Furthermore, the time of medicament application (1 week- 1 month) was found to have no significant effect on fracture resistance. Different types of intracanal medicaments (Ultracal XS, Bio-C Temp) and root canal sealers (AH Plus, Bio-C Sealer) have shown similar effects on root dentin fracture resistance at different time intervals. However, due to their tendency to leave residues on the dentine surface, both Ultracal XS and Bio-C Temp applications have negatively affected root dentine fracture resistance.