Influence of working distance and repeated use on the accuracy of the drilling system in guided endodontics

Abstract

Introduction: Partial or complete obliteration of root canals, because of progressive mineralization processes, constitutes a significant challenge in contemporary endodontic practice. These complex cases require a highly precise approach to minimize the risk of deviations, iatrogenic perforations, and loss of tooth structure. In this context, Computer Aided Design (CAD) and Computer Aided Manufacturing (CAM) technologies have allowed the development of guided navigation systems that optimize the planning and execution of endodontic access. Objectives: The objective of this study was to quantitatively evaluate the influence of working distance and the number of reuses on the accuracy of the bit-ring assembly used in guided endodontics procedures. The relationship between the repetition of clinical use and the angular and linear deviation in the drilling path is analyzed, to determine the functional impact of these factors on the accuracy of the assisted drilling system. Methodology: An experimental study was conducted to evaluate the accuracy of the drill-ring assembly in guided endodontics, considering the working distance and the number of uses. Bovine dentin discs drilled with high-speed steel drill bits (0.65 mm) at 1200 rpm and 4 N of torque, guided by 3D printed rings, were used. Deviation was measured with ImageJ® software and data was statistically analyzed using a two-way analysis of variance in GraphPad Prism 9. Results: This study analyzed the accuracy of the perforations made by a guided system, focusing on the variations recorded in the X and Y axes. On average a deviation of 0.28 mm was observed on the X axis and -0.43 mm in the Y axis, being the largest deviation detected at the height of disk number 7. To better understand the behavior of the system, a two-way ANOVA analysis was applied that evaluated the impact of the drilling depth and the number of times the instrument was reused. The results revealed no statistically significant differences, although depth explained a considerable proportion of the observed variability. In addition, when analyzing the trajectories of the boreholes, it was noted that they did not follow a constant direction, suggesting a random deviation without a clear pattern. Conclusions: Taken together, these findings indicate that neither the length of the perforation nor the reuse of the components significantly compromise the accuracy of the procedure. This reinforces the reliability of the static guides, which proved to be effective and stable, even after multiple uses and at different depths, always within the parameters evaluated in this study. General area of study: Dentistry. Specific area of study: Endodontics. Type of study: Original article.