The effect of intracanal medication variations on microhardness of simulated immature root dentin

Microhardness and Fracture Resistance of Radicular Dentin Treated with Different Concentrations of Calcium Hydroxide in Endodontic Regeneration Procedures

Purpose: to reveal the effect of different concentrations of prepared calcium hydroxide pastes (70%, 50%, and 30%) used in regenerative endodontic on microhardness and fracture resistance of radicular dentin. Material and methods: Different concentrations of calcium hydroxide (Ca(OH)2) were prepared with measured pH, then forty eight single rooted teeth were prepared and randomized into three groups according to Ca(OH)2 paste concentrations (12 samples each) and 12 samples were availed as control group. Group I: root canal contained 30% Ca(OH)2 paste. Group II: root canal contained 50% Ca(OH)2 paste. Group III: root canal contained 70% Ca(OH)2 paste. Samples were stored at 37 0C with 100% humidity for four weeks for subsequent microhardness and fracture resistance tests. Results: There was a statistically significant reduction of microhardness  and fracture resistance between test groups and control group (P≤ 0.05), group III showed a  significant reduction  in both microhardness and fracture resistance compared to group I. However, there was no significant difference in pH between different concentration of Ca(OH)2. Conclusion: Increasing concentration of Ca(OH)2 paste can negatively affect microhardness and fracture resistance of radicular dentin in revascularization procedure.

Comparison of the efficacy of three different supplementary cleaning protocols in root-filled teeth with a bioceramic sealer after retreatment-a micro-computed tomographic study

OBJECTIVE

The present study evaluated the efficacy of three different supplementary cleaning protocols on the removal of bioceramic-based root canal filling materials from oval-shaped canals.

MATERIALS AND METHODS

A total of 36 human mandibular premolars were instrumented and obturated with gutta-percha and iRoot SP using the single-cone technique. Retreatment was performed with ProTaper Universal retreatment files. The samples were randomly divided into the following supplementary cleaning protocols: conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI), and XP-endo Finisher R (XPR). The samples underwent micro-CT scanning to quantify the amount of residual filling materials after retreatment and after performing the cleaning protocols. The volume of filling material removal was analyzed by one-way analysis of variance and post hoc Bonferroni and Games-Howell tests (P < 0.05).

RESULTS

There were significant differences in the amount of root canal filling material removal in every comparison group (P < 0.05). The XPR removed significantly more residual filling materials (P < 0.01) followed by PUI and CSI (P < 0.05). Similar efficacy was found in the total root canal and all root thirds.

CONCLUSIONS

The additional use of XP-endo Finisher R and passive ultrasonic irrigation effectively removed the bioceramic-obturated root filling materials from the oval-shaped canals. However, none of the techniques completely removed the filling materials.

CLINICAL RELEVANCE

The XP-endo Finisher R and passive ultrasonic irrigation exhibited greater efficacy compared with syringe irrigation in the reduction of residual filling materials after retreatment in root-filled teeth with a bioceramic sealer.