A comparative evaluation of retrievability of Gutta percha, Resilon and CPoints for retreatment using two different rotary retrieval systems: An invitro study

INTRODUCTION : The success of endodontic treatment depends on thorough debridement of canal system, of infected or necrotic pulp tissue, microorganisms and complete sealing of the canal space, thus preventing persistence of infection and/or reinfection of the pulp cavity. A number of endodontic failure cases are being reported to the dental clinics which require surgical or nonsurgical retreatment. Nonsurgical retreatment requires regaining access to the entire root canal system through complete removal of the core filling material and sealer. For retreatment to be practical, the material should be removable from the root canal space. AIMS AND OBJECTIVES : To compare the removal ability of Gutta percha, Resilon and CPoints, for retreatment, using two rotary retreatment systems, Protaper and Mtwo and comparing volume percentage of residual obturating material in the root canal walls, after removal, using the Cone Beam Computed Tomography images. METHODOLOGY : Sixty freshly extracted single rooted mandibular premolars which were extracted for orthodontic purpose, were collected and were decoronated at the cemento-enamel junction, approximately 15mm from apex. They were randomly divided into six groups of ten teeth each. Biomechanical preparation using Protaper rotary files and obturation of root canals using Gutta percha, Resilon and CPoints, using their corresponding sealers, were performed for twenty teeth each. The obturation material was removed with Protaper rotary retreatment files for 10 teeth each from each group obturated with gutta-percha, Resilon and CPoint. The rest were removed using Mtwo rotary retreatment files. All teeth, after removal of obturation material was analysed using Cone Beam Computed Tomography, for checking the cleanliness of root canals and the remaining percentage volume of obturation material from each group was calculated and compared. RESULTS AND OBSERVATIONS : The analysis of the results show that the mean volume percentage of the residual material is least for RealSeal group with the removal by Protaper retreatment file(16.35±2.69 %) and the highest volume percentage of residual filling material was seen in the groups obturated by CPoint and removed by Mtwo retreatment file system (29.67±2.34 %). CONCLUSION : In this study, it is well demonstrated that the canals obturated with CPoints were least retreatable and those with RealSeal were the easiest ones to be retreated. Clinical significance : Many retreatment cases are being reported to our clinics nowadays. Root canal treatment failures occur when the treatment falls short of the acceptable standards. It is usually associated with procedural errors in infected tooth. It may be due to intra-radicular or extra-radicular infections or due to overfilling of root canals or inadequate coronal seal. Retreatment has to be done in such cases and hence the obturating materials used must be retrievable from the root canals. It is a consensus that all filling material must be removed during retreatment thus providing adequate disinfection of the root canal system and favours conditions for new filling. The three different materials in this study shows three different sealing efficiency which affects the retrievability of the material from root canal. Hence the retrievability of each obturating material from the canal walls was evaluated by measuring the percentage volume of residual root canal obturating material to the total volume of root canal after the obturating material is removed by two retreatment file systems