Impact of kinematics on the efficiency and safety of an engine-driven file for glide path preparation in MB2 canals of maxillary molars

Abstract

To evaluate the in uence of different kinematics on the e ciency and safety of an engine-driven le for glide path preparation in second mesiobuccal canals (MB2) of maxillary molars. In addition, the torsional resistance of the le was assessed after use. Methodology:Thirty-six maxillary rst and second molars with two canals in the mesiobuccal root were selected and the anatomy of the canals was veri ed by micro-CT. The teeth were divided into 4 groups (n = 9) according to the kinematics used for glide path preparation: continuous rotation (CR), 30°/150°r eciprocation (REC 30°/150°), 30°/90° reciprocation (REC 30°/90°), and 90° optimum glide path motion (OGP 90°). The duration of the procedure, number of canals in which the le reached the full working length (RFWL), canal volume before and after the procedure, rate of le fracture, and le torsional strength after use were evaluated. The ANOVA and Tukey tests or Kruskal-Wallis and Dunn tests were used for statistical analysis. ResultsNo signi cant differences among the groups were found for procedure duration, success at reaching the FWL, distance from the le to apex, and number of fractured les (P > 0.05). The CR group showed a signi cant decrease in rotation angle compared with REC 90° and OGP 90° groups (P < 0.05). There was no signi cant difference in canal volume among the groups (P > 0.05). ConclusionThe type of kinematics used did not affect the e ciency, success rate, and shaping ability of the le during glide path preparation. CR seems to induce more torsional stress than the other kinematics.

Evaluation of the Quantity of Extruded Debris through the Apical Foramen Using Optimum Glide Path Motion: An ex vivo study

“…These results may explain the formation of more debris in the RM group. In contrast, Araújo et al [14] found no signi cant differences among RM and OGP motion groups regarding canal volume changes, this result may be due to the small sample size.…”