بررسي آزمايشگاهي مقايسه مقدار دبري خارج شده از آپيكال فورامن در استفاده از تكنيكهاي آماده سازي دستي و چرخشي پروفايل

An Invitro Comparative Study of Apically Extruded Debris in Conventional and Rotary Instrumentation Techniques

Introduction: Common instruments have been used in root canal therapy are hand Stainless Still instruments. For the reason of difficulties in root canal preparation related to these instruments, the new generation of instruments from Ni-Ti alloys introduced. The purpose of this invitro study was to investigate of the quantity of debris extruded apically in straight canals by comparing conventional step-back technique and instrumentation using profile Rotary system at 3 different speeds: 1000 rpm, 8000rpm and 24000rpm (Collection of these speeds were decreased with micromotor to 1/6rpm) and the relationship between the amount of extruded debris and length of the root canal. Materials and Methods: 200 Mature human teeth with minimum curve were randomly divided in to 4 groups and prepared using step-back instrumentation and profile 4%, Taper series 29 rotary system at 3 different speeds 1000 rpm, 8000rpm and 24000rpm. Extruded debris through the apical foramen during instrumentation was collected on preweighted vials containing distilled water. Then the vials placed into a microoven at 150° to drv and then weighted again. the difference was recorded as the weight of the extruded debris. Eight control vials (2 for each group) were weighted and filled with distilled water, dried and reweighed. The mean weight of extruded debris for each group was statistically analysed. T student statistical with variance analysis were used in this study. Results: The results showed that step-back instrumentation (group 1) produced significantly more debris than the other groups and the difference in the amount of produced debris among groups 2,3,4 was not significant. The amount of extruded material increased in proportion to length of the canal that was significant in group 1 but not significant in groups 2,3,4. Conclusion: step- back instrumentation (group 1) produced significantly more debris than the other groups.