Apical debris extrusion of ProTaper Next versus iRaCe Rotary files in curved root canals (An in vitro Study)

Background: This study quantitatively compared the apical extrusion of debris during the shaping of moderately to severely curved mandibular molar mesio-buccal canals using two rotary systems: ProTaper Next and iRace. Methods: Forty mesial roots from selected human mandibular molars, with inclusion criteria requiring a mesiobuccal canal curvature ranging from 25 to 35 degrees were selected. Then, teeth were mounted and scanned via CBCT to confirm anatomy. The roots were sectioned, and the mesiobuccal canals were instrumented to an apical size 30 using either ProTaper Next (PTN) or iRace (iR) systems (n=20/group) in a torque-controlled motor. Apically extruded debris was collected into pre-weighed Eppendorf tubes using a Myers-Montgomery apparatus, desiccated, and re-weighed to determine the net debris mass. A one-way ANOVA was employed for statistical analysis, with post hoc comparisons conducted using Tukey's HSD test. A p-value of less than 0.05 was considered statistically significant.Results: While both instrumentation techniques resulted in apical debris extrusion, quantitative analysis demonstrated a statistically significant difference between the groups. A significantly higher mean volume of debris was produced by the iR system in comparison to the ProTaper Next system (p < 0.001).Conclusions: The ProTaper Next (PTN) file system demonstrated a statistically significant reduction in apical debris extrusion compared to the iRace system during the preparation of curved mesial canals of mandibular molars.