Real-Time Three-dimensional Dynamic Navigation for Root Post Space Preparation in Root Canal-treated Teeth: an In vitro Study

Introduction The aim of this study was to investigate the feasibility of a real-time three-dimensional dynamic navigation system (3D-DNS) for root post space preparation (RPSP) in root canal-treated teeth and compares the accuracy and efficiency of 3D-DNS to freehand (FH) for RPSP. Methods Fifty-four maxillary molars were divided into two groups: 3D-DNS (n = 27) and FH group (n = 27). Cone beam computed tomography (CBCT) scans were taken pre- and post-operatively. The drilling path for the RPSP was virtually planned in the pre-operative CBCT scan in the X-guide software (X-Nav Technologies, Lansdale, PA). For the 3D-DNS group, the RPSP drilling was conducted under dynamic navigation. The 3D deviations and angular deflection (AD) were calculated. The residual dentin thickness (RDT) was determined after RPSP. The operation time and the total number of mishaps were recorded. Shapiro-Wilk, t-test or Mann-Whitney rank sum, weighted Cohen's kappa, and Fisher exact tests were used (p<.05). Results The RPSP was completed in all samples (54/54). The 3D-DNS was more accurate than the FH, with significantly fewer 3D deviations and AD (All, p < .05). The 3D-DNS required less operation time than the FH (p < .05). For the 3D-DNS, no teeth had RDT < 1 mm, whereas 6/27 in the FH showed RDT < 1 mm after the RPSP. There was no difference in the total number of mishaps (p > .05). Conclusion Within the limitations of this in vitro study, the 3D-DNS is feasible for RPSP. The 3D-DNS improved the accuracy and efficiency of RPSP. The dynamic navigation system can potentially become a safe and reliable technology for RPSP.