Glide path with a reciprocating driven pathfinding instrument: performance and fracture rate

Abstract Introduction This study assessed the number of mesial and distal canals of mandibular molars in which the R-Pilot pathfinding reciprocating instrument reached the working length (WL) during macro glide path procedure. Fracture and deformation rates were also evaluated. Methods One-hundred and fifty-six root canals of 52 teeth were scouted to the length of the apical foramen. Then, the R-Pilot instrument was positioned at the canal orifice and activated. The instrument was moved using a pecking motion and light apical pressure. This procedure was repeated in an attempt to reach the WL. The type of fracture and/or instrument deformation was assessed by scanning electron microscopy, while the roots with fractured instruments were scanned through micro-computed tomography. The percentage frequency distribution of fractures, deformations, and root canals in which the R-Pilot reached the WL were recorded and statistically compared using the Pearson’s chi-square test with α = 5%. Results R-Pilot instruments reached the WL in 139 root canals (89.10%) and chi-square test showed a significant difference between the observed frequencies and the expected frequencies (x 2 = 95.41, p = 0.000). The observed frequencies of fractures (2.56%) and deformations (1.92%) were also significantly lower than the expected (fracture: x 2 = 140.41, p = 0.000; deformation: x 2 = 144.23, p = 0.000). Fractures occurred mostly at the apical and curved parts of the root canals. Conclusion R-Pilot reached the WL in 89.10% of the root canals of mandibular molars with fracture and deformation rates of 2.56% and 1.92%, respectively.