Effect of Heat-treated and Conventional Retreatment Files on Removal of Gutta Percha and Remaining Dentin Thickness by CBCT Analysis: An in vivo Study

Abstract

The success of endodontic treatment depends on effective canal shaping, thorough chemo-mechanical debridement, and the achievement of a three-dimensional hermetic seal. Despite a reported success rate of up to 97%, failures may occur, often necessitating endodontic retreatment. Complete removal of gutta-percha while preserving radicular dentin is critical for the long-term prognosis of retreated teeth. Aim: To evaluate and compare the efficiency of ProTaper Universal Retreatment files, Solite RS3 retreatment files, and R-Endo retreatment files in the removal of gutta-percha and their effect on remaining dentin thickness using CBCT analysis. Materials and Methods: Sixty extracted human single-rooted mandibular premolars diagnosed with post-treatment apical periodontitis were included in this study. Samples were randomly allocated into three groups (n = 20 each) using a sealed envelope technique: Group 1 – ProTaper Universal Retreatment files, Group 2 – Solite RS3 Retreatment files, Group 3 – R-Endo Retreatment files. Preoperative CBCT scans were obtained to assess baseline dentin thickness. Standardized access cavity preparation was performed under rubber dam isolation using a sterile high-speed round diamond bur. Retreatment procedures were carried out according to the respective manufacturer’s instructions for each file system. Final irrigation was performed using normal saline. Postoperative CBCT analysis was conducted to evaluate the amount of remaining filling material and changes in dentin thickness. Results: All experimental groups demonstrated residual filling material following retreatment procedures. However, Solite RS3 and R-Endo systems showed significantly greater efficiency in gutta-percha removal compared to the ProTaper Universal Retreatment system. Additionally, the R-Endo group exhibited significantly greater preservation of remaining dentin thickness when compared to the Solite RS3 group. Conclusion: Within the limitations of this study, none of the retreatment systems achieved complete removal of gutta-percha. However, R-Endo and Solite RS3 systems were more effective than ProTaper Universal Retreatment files. R-Endo demonstrated superior preservation of dentin thickness, suggesting it may be a safer and more conservative option for endodontic retreatment.