Shaping ability of ProTaper instruments in flattened root canals

Objective: To evaluate the instrumented perimeter in flattened root canals by the last apical instrument of ProTaper system. Methods: For this study 30 mandibular central incisors were obtained from the tooth bank of University of Joinville, which were divided in six groups (n = 5): group I – F1 instrument associated with 2.5% sodium hypochlorite; group II – F2 instrument associated with 2.5% sodium hypochlorite; group III – F3 instrument associated with 2.5% sodiumhypochlorite; group IV – F1 instrument associated with distilled water; group V – F2 instrument associated with distilled water; group VI -– F3 instrument associated with distilled water. Thespecimens were prepared following the technique recommended by the manufacturer and between instruments 5 mL of a irrigant solution were used. The specimens were then submitted to the histological preparation and analysis with the Scion Image software. Results: A statistically significant difference in the instrumented area was found between all the instruments, but not between irrigating solutions. Conclusion: It can be concluded that none of the instruments of ProTaper system promoted fully instrumented root canals, however the groups that used F3 instrument with or without solution of sodium hypochlorite and 2.5% were more effective.