S. G. Khirtika, Sindhu Ramesh

Abstract

To compare the incidence of dentinal cracks and detachments after instrumentation using different types of NiTi files in rotary motion. 36 human extracted mandibular central incisors were taken and divided into four groups (n=9 per group). Group 1 - Hand instrumentation, Group 2 - ProTaper Universal, Group 3 - Protaper Next, and Group 4 - M-two files in rotary motion. Specimens were then sectioned horizontally and viewed under dental operating microscope. Roots prepared with hand files shows the lowest percentage of dentinal cracks and detachments (7%); whereas in roots prepared with ProTaper Universal, ProTaper Next, and M-two was 66, 20, and 13%, respectively. There was no significant difference between ProTaper Next and M-two group (P < 0.05). Apical cracks developed in 2 of 27 teeth with rotary file systems. Apical dentinal detachments developed in 1 of 27 teeth with rotary file systems. No crack was resultant from instrumentation with rotary files terminating 1mm short of apical foramina. Only in cases when instrumentation with rotary files terminated short of the apex, less cracks and detachments occurred. More apical cracks appeared in teeth with deviated apex.