Properties of Mechanical Endodontic Instruments and the Quality of the Simulated Canal Preparation

Abstract

Background. Successful root canal treatment is associated with correct canal preparation. The quality of mechanical preparation depends on many factors. Researchers are still looking for the optimal methods and instruments for this purpose. Objectives. The aim of the research project was to analyze the structure and work of mechanical files and the effect of simulated canal preparation with a single curvature. Material and Methods. The study involved the reciprocal files: WaveOne® (Dentsply Maillefer) and Reciproc® (VDW) and the rotary file ProTaper Next® (Dentsply Maillefer). The study used 30 resin blocks (Endo-Training-Bloc®, Dentsply-Maillefer) of the artificial canals with a single curvature (ie. L-type canals). Photographs were taken before and after preparation. Using computer images were imposed on and measurement points set. The amount of material removed was determined as the distance between the measuring point and the wall of the canals after the preparation. Results. The greatest mean changes in the working length were observed in the group Reciproc, the smallest in the group ProTaper Next. The highest average amount of material in all groups was removed from the inner wall of the central part of the canal. The greatest value was achieved in the WaveOne group. The lowest value was obtained in the group Reciproc. The best canal centralization was obtained at 8 mm from the apical foramen, the worst at 5–6 mm. Conclusions. The tested instruments prepare simulated canals in a satisfactory manner, but do not provide optimum results. Therefore, preparing the canals of complex anatomy with a large file and a large taper carries the major risk of complications. Comparison of WaveOne, Reciproc and ProTaper Next system based on a sequence of files showed statistically significant differences.