Endodontic access with different computer navigation systems in calcified root canals

Background: A range of computer-aided navigation techniques to aid endodontic access cavity preparation have been developed. The aim of this study was to analyze the accuracy of access cavities prepared with the aid of computer-aided static navigation (SN), computer-aided dynamic navigation (DN), and navigation based on augmented reality (AR) compared with a conventional freehand (FH) method in extracted mandibular teeth with calcified root canal systems. Methods: Forty single-rooted mandibular teeth were divided into 4 groups, and preoperative cone-beam computed tomographic scans and digital impressions through an intraoral scan were obtained. Access cavities were then prepared using SN (n = 10), DN (n = 10), AR (n = 10), or FH (n = 10), and postoperative cone-beam computed tomographic scans of each tooth were obtained to evaluate deviation of the access cavities between the virtually planned preoperative preparations and the actual postoperative preparations. Analysis of variance followed by Tukey post hoc tests were used to identify significant differences in deviation, with P values below .05 being considered significant. Results: Significant deviations of the access cavities were found coronally between SN and DN (P < .001), SN and AR (P < .001), DN and FH (P = .015), and AR and FH (P = .003) and apically between SN and AR (P = .003) and AR and FH (P = .006). There were significant differences at angular level between SN and DN (P < .001), SN and AR (P < .001), and SN and FH (P = .013). Conclusions: AR was associated with significantly smaller differences in dentin removal and cavity alignment than the SN, DN, and FH methods. Practical Implications: Endodontic access cavity preparations using AR technology were more accurate than preparations using other techniques and have the potential to be adopted in clinical practice when canal systems are obliterated.