Efficacy of Different Retreatment Techniques in Molar Root Canals: An ex vivo Study

The aim of this study was to evaluate the efficacy of two different rotary instruments with and without a solvent versus hand files in the removal of gutta-percha root fillings. Sixty extracted human molar teeth were used for this study. Mesiobuccal canals of teeth were prepared and filled with sealer and guttapercha. Before retreatment was applied, radiographs were taken. Specimens were divided into six groups: Group 1:Protaper Universal Rotary Retreatment System, Group 2: Protaper Universal Rotary Retreatment System with eucalyptol , Group 3: Profile, Group 4: Profile with eucalyptol, Group 5: Hedström files Group 6: Hedström files with eucalyptol. During retreatment procedure, the operating time was recorded. After removing root canal fillings from the canals, radiographs were taken, digitalized and analyzed in a software for image analysis. The ratio of remaining obturation material to root canal surface was derived. In this study gutta-percha and sealer remnants were present within the root canal in all test groups. Statistical analysis showed that there was no significant difference between the techniques (P 0.05); however, a significant statistical difference (P 0.001) was found between the groups in regard to retreatment time. Although completely clean root canal walls were not produced with any of the techniques investigated, groups which used solvent and rotary instruments demonstrated more shorter retreatment time than other techniques. According to these results, it can be suggested that sealer or gutta-percha solvents and rotary instruments are useful for root canal retreatment.