Journal of AdvancedMedical and Dental Sciences Research

Background: Successful endodontic therapy depends upon triad of proper diagnosis, thorough biomechanical preparation and three dimensional obturation of root canal system.The purpose of this study is to compare the dentinal crack formation while using hand files, Protaper Next rotary files, Hyflex EDM rotary files, K3 XF rotary files, and Twisted rotary files. Materials & methods: Sixty single rooted mandibular premolar teeth were divided into 6 groups as follows:-Group I: Ten specimen canals were left unprepared.Group II: Ten specimen canals were prepared with Hand K Files (Mani).Group III: Ten specimen canals were prepared with The ProTaper Next files (Dentsply Maillefer) in the sequence Pro-Taper Universal SX and then ProTaper Next X1(17/.04) and X2(25/.06) at a rotational speed of 300 rpm and 200 g/cm torque. Group IV: Ten specimen canals were prepared with Hyflex EDM rotary files (ColteneWhaledent) size 25 with a variable taper from .08 at the tip up to .04 in the coronal part, in continuous rotation according to the manufacturer’s instructions.Group V: Ten specimen canals were prepared with K3 XF rotary files (SybronEndo) K3XF rotary instruments were used in a crown down approach with the sequence of 25/.10 and 25/.08 for coronal shaping followed by 25/.04 upto working length and then master apical file 25/.06 was used.Group VI: Ten specimen canals were prepared with Twisted rotary files(Sybron Endo) in the following sequence at 500 rpm: 25/.08, 25/.04 and finally 25/.06 file as master apical file. All of the roots were sectioned perpendicular to the long axis at 3, 6, and 9 mm from the apex. Then the slices were examined for cracks under stereomicroscope.Roots were classified as “defected” if at least one of the three sections showed either a craze line, partial crack, or a fracture. All the results were analyzed by SPSS software. Results: The total number of cracks caused observed in Control, Hand Files, ProTaper NEXT, Hyflex EDM, K3 XF and Twisted groups was found to be 0/30 (0%), 2/30 (6.67%), 10/30 (33.33%), 9/30 (30%), 12/30 (40%) and 10/30 (33.33%) respectively. The highest total number of cracks are caused by Group V (K3 XF) whereas least number of cracks are present in Group I ( Control). Group II (Hand File) showed least number of cracks among various file systems used in the study. Group IV (Hyflex EDM) showed least number of cracks among various rotary file systems used in the study. Statistical significant difference in total number of cracks was observed in six groups (P<0.001). Conclusion: All the instruments used in the study, including hand K file, induced dentinal defects,but this is less in comparison to the rotary file systems. Key words: Dentinal Cracks, Hyflex, Protaper, Twisted, K3XF