Effect of modified Hedstrom files on instrumentation area produced by ProFile® instruments in oval canals

Objective. To study the effect of a modified Hedstrom file called IqFile on the instrumentation shape of oval canals prepared with ProFile((R)) instruments. Study design. Fifty extracted premolars were divided into 3 groups of 16 teeth each. Group 1 was subjected to ProFile 0.04 rotary instrumentation to a size 6. Group 2 followed the same technique, but also received buccolingual hand instrumentation with IqFiles to ISO size 70. Group 3 was instrumented similarly to group 2 but unmodified Hedstrom files were used. Teeth were sectioned at 1 and 3 mm from working length and photographed at 26x magnification. AutoCAD was used for measuring the percentage of instrumented area of the canal. Results. AOVA revealed that Group 2 was significantly better than Groups 1 (P =.00) and 3 (P =.00) at the 1 mm level. At the 3 mm level Group 2 was significantly better than Group 1 (P =.03), but no differences were found between Groups 2 and 3 (P =.15). Conclusion. The combination of ProFile and IqFile was found more effective in instrumenting oval canals at both the 1 and the 3 mm levels. However, at the 3 mm level no difference was detected between the use of IqFiles and the use of unmodified Hedstrom files.