Accuracy of Endodontic Access Cavities Performed Using an Augmented Reality Appliance: An In Vitro Study.

INTRODUCTION: The purpose of this study was to compare and contrast the accuracy of endodontic access cavities created using an augmented reality appliance to those performed using the conventional technique. MATERIALS AND METHODS: 60 single-rooted anterior teeth were chosen for study and randomly divided between two study groups: Group A-endodontic access cavities created using an augmented reality appliance as a guide (n = 30) (AR); and Group B-endodontic access cavities performed with the manual (freehand) technique (n = 30) (MN). A 3D implant planning software was used to plan the endodontic access cavities for the AR group, with a cone-beam computed tomography (CBCT) and 3D intraoral surface scan taken preoperatively and subsequently transferred to the augmented reality device. A second CBCT scan was taken after performing the endodontic access cavities to compare the planned and performed endodontic access for accuracy. Therapeutic planning software and Student's t-test were used to analyze the cavities at the apical, coronal, and angular levels. The repeatability and reproducibility of the digital measurement technique were analyzed using Gage R&R statistical analysis. RESULTS: The paired t-test found statistically significant differences between the study groups at the coronal (p = 0.0029) and apical (p = 0.0063) levels; no statistically significant differences were found between the AR and MN groups at the angular (p = 0.6596) level. CONCLUSIONS: Augmented reality devices enable the safer and more accurate performance of endodontic access cavities when compared with the conventional freehand technique.

Influence of the Geometrical Cross-Section Design on the Dynamic Cyclic Fatigue Resistance of NiTi Endodontic Rotary Files-An In Vitro Study.

The aim of this study was to analyze and compare the influence of the geometrical cross-section design on the dynamic cyclic fatigue resistance of NiTi endodontic rotary files. MATERIALS AND METHODS: Forty sterile endodontic rotary files were selected and distributed into the following study groups: A: 25.06 double S-shaped cross-section NiTi alloy endodontic rotary files (Mtwo) (n = 10); B: 20.04 rectangular cross-section NiTi alloy endodontic rotary files (T Pro E1) (n = 10); C: 25.04 convex triangular cross-section NiTi alloy endodontic rotary files (T Pro E2) (n = 10); and D: 25.06 triangular cross-section NiTi alloy endodontic rotary files (T Pro E4) (n = 10). A cyclic fatigue device was used to conduct the static cyclic fatigue tests with stainless steel artificial root canal systems with 200 µm and 250 µm apical diameter, 60° curvature angle, 3 mm radius of curvature, 20 mm length, and 4% and 8% taper. The results were analyzed using the ANOVA test and Weibull statistical analysis. RESULTS: All the pairwise comparisons presented statistically significant differences between the time to failure and number of cycles to failure for the cross-section design study groups (p < 0.001). CONCLUSIONS: the double S-shaped cross-section of Mtwo NiTi endodontic files shows higher cyclic fatigue resistance than the rectangular cross-section of T Pro E1 NiTi endodontic files, the convex triangular cross-section of T Pro E2 NiTi endodontic files, and the triangular cross-section of T Pro E4 NiTi endodontic files.