The effect of single adjustable post system on bond strength in severely damaged root canals

This in vitro study aimed to evaluate the effect of fiber sleeve, as part of a single adjustable post system, on bond strength in root canals, both with and without aging in a chewing simulator. Sixty single-rooted mandibular premolar teeth were selected for the study. The teeth were divided into two groups: one with fiber kılıfs and one without. Each group was further divided into two subgroups, with half of the samples in each group subjected to aging in a chewing simulator, resulting in four groups (n=15). Each sample was sectioned into 1 mm thick slices using a precision cutting device, yielding three discs corresponding to the coronal, middle, and apical thirds of the root. Push-out tests were performed on these discs using a universal testing machine, and the peak force (in Newtons) was recorded. Bond strength was calculated by dividing the peak force by the surface area of the dentin. Fracture types were analyzed under 40x magnification with an operating microscope. Statistical analysis was conducted using one-way ANOVA and Tukey's tests (p=0.05). The highest bonding strength was observed in the S group, where the kılıf was used, and it was significantly different from the P group (p<0.001). When all groups were compared, the highest bonding strength values were found in the coronal third, which was significantly higher than in the middle and apical sections (p<0.05). A significant difference was found when comparing the bonding strengths of the S and S+Ç groups (p=0.029), whereas no significant difference was observed between the P and P+Ç groups (p=0.999). Among the fracture types, adhesive failure between dentin and cement was the most common. Within the limitations of this study, the fiber sleeve enhances bonding strength. Although aging procedures reduce bonding strength values, no statistically significant difference was observed in the sleeveless groups, whereas a statistically significant difference was noted in the groups where the sleeve was used.