The effects of different nickel-titanium instruments on dentinal microcrack formations during root canal preparation

OBJECTIVE: The aim of the present study was to investigate the incidence of dentinal microcracks caused by different preparation techniques. MATERIALS AND METHODS: 120 extracted human mandibular incisor teeth were divided into five experimental groups and one control group (n = 20): Group 1: Hand preparation with balanced force technique up to #25 K-file. Group 2: Preparation with only ProTaper F2 instrument in a reciprocating movement. Group 3: Preparation with Reciproc R25 instrument in a reciprocating movement. Group 4: Preparation with ProTaper instruments up to F2 instrument. Group 5: Preparation with ProTaper Next instruments up to X2 instrument. No procedure was applied to control group. The roots were sectioned horizontally at 3, 6 and 9 mm from the apex and examined. Absence or presence of dentinal microcracks was noted. RESULTS: The Chi-square test was performed to compare the appearance of cracked roots between all groups. There were no significant differences among the groups (P > 0.05). CONCLUSIONS: In conclusion, except the hand file and control group, all experimental groups showed microcrack formations.