Effect of Profile and Race rotary systems on original canal anatomy in simulated severely curved canals

Recent advances in technology have permitted manufacturers to produce endodontic files from NiTi alloy and rotary systems. According to manufacturers, these files maintain original canal shape better than hand files and reduce treatment time. The aim of this study was to compare a new rotary system (Race) with an older one (Profile) in maintaining the original shape of curved canal and the working length as well as the procedural accidents rate. In this experimental study, 40 polyester blocks with curved canals (45), were fabricated and divided into 2 groups. After primary working length determination and staining with methylene blue, photographs were taken. Canal preparation was done with Profile and Race rotary systems according to manufacturers and working length was measured again. Canal staining by eosin was performed and photographs were taken for the second time. The two images were superimposed and changes in canals anatomy in 5 sections were recorded. Data were analyzed by t test with p<0.05 as the limit of significance. There was no significant difference in inner and outer canal walls transportation between 2 groups (P> 0.05). Changes in working lengths and procedural accidents were similar in the studied groups (P> 0.05). Based on the results of this study, changes in canal anatomy and working length of simulated severely curved canals as well as procedural accidents rate are similar in two rotary systems and both are suitable for canal preparation.