Interaction Between Access Cavity Design and NiTi Rotary Systems on Apical Debris Extrusion: An In Vitro Study

Background/Objectives: New-generation files and cavity designs may affect apical debris extrusion. This study compared the TruNatomy (TRN) and RaceEvo (REV) files regarding the amount of apically extruded debris (AED) of mandibular molars with different access cavity designs: Traditional Endodontic Cavity (TEC) and Contracted Endodontic Cavity (CEC). Methods: Sixty extracted mandibular molars with moderate mesial root curvature were divided into 4 groups (n = 15) according to the cavity design and instrumentation systems used: TEC/TRN; TEC/REV; CEC/TRN; and CEC/REV groups. The shaping of mesiobuccal canals was done at 37 °C, and irrigation was performed with bidistilled water. The AED was collected inside a glass jar and then desiccated for 5 days at 70 °C, with the amount of AED calculated by weighing jars. A two-way analysis of variance and the Bonferroni test were used for the statistical analysis of the data, with the significance level set at p < 0.05. Results: There was a significant difference between both instrumentation systems and access cavity designs in terms of AED (p < 0.05). The highest mean value was obtained in the TEC-TRN group, and the lowest mean value was obtained in the CEC-REV group. The REV file system caused significantly less AED than TRN within the TEC design; no significant difference was found between file systems within the CEC design (p > 0.05). Conclusions: The TEC and the TRN system were associated with a higher AED. Clinical Significance: The CEC would be a good choice in the clinic to decrease AED.