The influence of cervical preflaring of root canal on determination of initial apical file using Gates Glidden drills, Protaper, Race and diamond-coated Galaxy files.

AIM: To investigate the influence of cervical preflaring on apical file size determination using four different rotary instruments. MATERIALS AND METHODS: Fifty root canals from extracted human maxillary premolars with complete root formation, straight roots were used for the study. Access opening was done and the working length established with 8 no K-file for each canal. Teeth were randomly divided into five groups of 10 canals. In Group 1--no preflaring was done and acted as control and in Groups 2, 3, 4 and 5 cervical and middle third preflaring of the root canals were done using Gates Glidden drills, Protaper instruments, Race instruments and Galaxy files respectively. After preflaring, the apical file size determination was done and the initial apical file (IAF) was fixed at the working length. Teeth were sectioned transversally 1 mm from the apex, with the binding file in position. The samples were imaged under stereomicroscope with 30* magnification. Root canal and file maximum diameters were recorded for each sample. The readings were subjected to analysis of variance test and Scheffe's multiple comparison test. RESULTS: Preflaring with Race instruments lead to most accurate determination of the IAF. It was followed by Protaper, Galaxy files and Gates Glidden drills. CONCLUSION: Traditional method of apical size determination may lead to a substantial underestimation of actual canal size. Cervical preflaring increases the accuracy of apical size determination. CLINICAL SIGNIFICANCE: Thus, cervical preflaring is recommended before selection of IAF as it increases the accuracy of apical size determination.