Evaluation of volumetric substance loss and precision in targeted endodontic re-treatment with guided versus conventional access cavity preparations: An in vitro study

INTRODUCTION: Root canal retreatment is typically viewed as an “all or nothing” approach. Whether there is periapical pathosis or not, it is advised that all restorative and obturation materials be removed from all roots. Selective root retreatment, a new therapeutic strategy, allows retreatment to be restricted to a single root or multiple roots exhibiting periapical pathosis. To address the issues, “guided endodontics,” a unique guided technique for the preparation of apically extended access cavities, was introduced. MATERIALS AND METHODS: In this in vitro experimental study, 22 freshly extracted two-rooted maxillary first premolars were selected and divided into two groups (n = 11). Pretreatment cone-beam computed tomography imaging of all teeth was performed. Root canal treatment was performed for all samples followed by postendodontic composite restorations with the occlusal stamp technique. Then targeted endodontic retreatment (TER) was done with the conventional method and guided method respectively. The tooth substance loss was measured and evaluated using Ez3D-i-3D-software (VATECH) and work precision was determined by calculating the dentinal loss. Statistical data analysis was done by Independent t-test for substance loss measurement and Chi-square test was used to measure the dentinal loss. RESULTS: TER with conventional method showed significantly higher substance loss with t = 4.591 (P < 0.05) and significantly higher dentinal loss measured in conventional method (P < 0.05). CONCLUSION: In comparison to traditional TER, TER using a customized bur and three dimensions (3D)-guide results in much less substance loss. The dentinal loss was much lower in 3D-guided approach.