Effect of Multi-use of Novel Ni-Ti instrument on Root Canal Filling Material Removal and Its Cyclic Fatigue Resistance
Project no. 373 · Status: Kapanmış · 2016
Summary
Aim: The aim of the present study was to evaluate the effect of multi-use of Reciproc Blue instruments (#25.08) on root canal filling material removal and its cyclic fatigue resistance during retreatment procedure in mandibular molar teeth. Methods: Seventy-two mandibular molar teeth with 20°-38° mesial root canal curvature angle and 5-8 mm radius, and straight distal root canals (0°-5°) were selected. The root canals were prepared using the Reciproc #25 file and filled with single cone R25 gutta-percha. Then the teeth were divided into three experimental groups with similar root canal curvature (Grup 1=12 teeth, Grup 2=24 teeth, Grup 3=36 teeth). Twelve Reciproc Blue 25 instruments for each experimental group were included in the study. In Group 1, each R25 blue file was used to remove the root canal filling material of 1 molar tooth; in Group 2, each file was used to remove the root canal filling material of 2 molar teeth, and in Group 3, each file was used to remove the root canal filling material of 3 molar teeth. A stainless steel artificial canal with a 90° angle and 3 mm radius of curvature was used for the testing process. Time to fracture was recorded in seconds by means of the video camera. For each instrument, the number of cycles to fracture (NCF) was calculated. Additionally, the remaining root canal filling material was calculated from digital radiographs for each tooth in group 3 using Image J software. Results: The NCF values of the instruments in Group 1 were significantly higher than those of Group 2 and Group 3 (P<0,05). While there was no difference between the first use of the instrument and the second time in terms of the amount of remaining gutta-percha (p>0.05), the difference between the first time use and the third-time use was statistically significant (P<0,05). Although no instrument fracture was observed in any group during the whole study, it was observed that cyclic fatigue resistance decreased after the second use of Reciproc Blue files. Conclusions: According to the data we obtained, the use of Reciproc Blue files in two molar teeth during retreatment procedure is not a risk factor for instrument fracture and can effectively remove root canal filling material similar to the first use.