COMPARATIVE EVALUATION OF EFFICACY OF NEO ENDO RETREATMENT FILES BY AUTOCLAVE AND COLD STERILIZATION AFTER EACH USE - AN INVITRO STUDY

Aim: The aim of the study is comparative evaluation of efficacy of neo endo retreatment files after autoclave and cold sterilization. Materials And Methods: 45 human mandibular premolars with a single straight root canal were selected and decoronated leave 16mm of root.The working length was determined by subtracting 1mm from above measurment. Canal preparation was done with Neo endo flex rotary files (25/6) and were obturated with GP size 25/6% .After 2 weeks of storage in normal saline they were randomly divided into three groups .In Group A (5 sub-groups :A1, A2, A3, A4 and A5 of 3 sets of specimens) Neo endo retreatment files were subjected to sterilization by autoclaving.In group B files were sterilized by cold sterilization with 2.4% Glutaraldehyde solution for 12 hours.In Group C files were cleaned using soap and water . Statistical analysis was done with One-way ANOVA Test followed by Tukeys post hoc test to compare the mean remaining GP & time taken between different groups and usage times. Result: All samples showed GP remnants. Irrespective of the sterilization methods used, the amount of remaining GP increased sequentially from first to fifth use along with usage time. The remaining GP was lesser in the group A where sterilization was done by autoclave, and remaining GP was highest in Group C where no sterilization was done. The remaining GP of Group B ( Cold sterilization) was higher than Group A and lower than Group C. Conclusion :From the findings of present study it can be concluded that Autoclave sterilization causes least changes to the physical properties of the files when compared to Gluteraldehyde sterilization which adversely effects the cutting efficiency of the files. Unsterilized files exhibits least cutting efficiency resulting in reduced gutta percha removal from the canals. Also the number of use was a determining factor for cutting efficiency. Reduction in the cutting effectiveness of instruments may increase operating time and it could take longer to remove the material from root canal.