RESUMO
Background: Self Adjusting Files have been introduced to overcome the disadvantage of protaper rotary files, especially for oval root canal centering. Aims and Objectives: To evaluate the canal centering ability between rotary protaper and self adjusting file in oval shaped canals using cone beam computed tomography. Methods:The study was carried out on 20 single rooted mandibular premolars. To compare the canal centering ability produced by different techniques, pre-instrumentation, post-instrumentation, cross section images of specimen at 3, 6 and 9 mm from the apex were obtained from the 3D CBCT images of each individual group. The images captured digitally using Image Tools Software were compared. Results: Inter group comparison of mean ratio of both the groups at 3, 6 and 9 mm after preparation of canal showed statistically significant difference between both the groups (p<0.05). Intra group comparison of mean ratio of both the groups at 3, 6 and 9 mm after preparation of canal showed that the difference between both the groups was not statistically significant (p>0.05).Conclusion: The canal centering ability of self adjusting file was efficient than protaper rotary files.
RESUMO
Objective To compare the effect of different nickel-titanium rotary files on fracture resistance of teeth by observing status of dentinal microcracks after root canal preparation with.Methods 6 5 mandibular anterior teeth with single oval canal were randomly divided into three experimental groups (n=20)and a control group (n=5),SAF、ProTaper Universal and ProTaper Next system were used to prepare root canal in experimental groups,while the control group were left unprepared.Roots were sectioned from 3,6,9 mm to the apex,its status of dentinal microcracks was evaluated under a stereomicroscope.Results Root fracture inci-dence rate of group ProTaper Universal was significantly higher than that of group SAF and group ProTaper Next (P0.05).Conclusion Roots with oval shaped canal prepared with SAF and ProTaper Next produce less dentinal microc-racks,which decrease risk of vertical root fracture.