LIFESPAN OF NITI ROTARY FILES WITH 360°ROTATION AND RECIPROCATING MOTION

Objective: To assess the life of two different rotary nickel-titanium (NiTi) instruments in curved canals with complete protocol, by using 360°rotation motion and reciprocating motion. Materials and Methods: About one hundred and seventy extracted maxillary and mandibular molars were taken from which two hundred curved root canals were selected and randomly divided in 2 groups, for analyzing the number of uses of rotary files. One hundred curved canals were prepared with Hyflex EDM 25/~ (coltene) in 360°continuous motion and one hundred canals were prepared with Reciproc R25 (VDW) in reciprocating motion to full working length. One file was used to prepare root canals until fractured. Every file used was coated with 17% EDTA and copious irrigation with 2.5% NaOCl was done. t-test was used to analyze data. Results: A total of 7 Hyflex EDM 25/~ and 10 Reciproc R25 files were used to prepare 200 curved root canals, 100 with each file. The average life of one Hyflex EDM 25/~ file was 13±1.50 canals and of Reciproc R25 was 9±1.59 canals. Among Hyflex EDM one file prepared maximum number of 15 canals and among Reciproc maximum canals prepared by one file were 13. There was a statistically significant difference between the two groups (p < 0.001). Conclusion: Hyflex EDM25/~ and Reciproc R25 can safely prepare 13 and 9 canals respectively to full working length if complete protocol is followed.