Development and accuracy assessment of a crown lengthening surgery robot for use in the esthetic zone: An in vitro study

Crown lengthening surgery has been widely used to enhance the health and esthetics of anterior teeth, and its accuracy significantly influences surgical outcomes. However, the feasibility and accuracy of a robot system for crown lengthening surgery remains unknown. The purpose of this in vitro study was to develop a crown lengthening surgery robot and evaluate its accuracy. A robotic crown lengthening surgery system consisting of a robotic arm, a robotic software system, and an optical tracking device was designed. Intraoral scanning and cone beam computed tomography (CBCT) were performed on 18 artificial dentition models. The data were imported into the planning software program to synthesize a surgical path for gingivectomy and alveolectomy. Subsequently, a robotic arm equipped with a high-speed handpiece was used to perform these surgical procedures. Postoperatively, the models were rescanned for evaluation, with the accuracy (trueness ±precision) of the surgical outcomes of gingivectomy and alveolectomy being assessed from the trajectories in the highest, lowest, and overall regions. Differences between groups were analyzed by using the independent sample t test and the Levene test (α=.05). Crown lengthening surgery was feasible in vitro using the robot developed in this study. The overall robot-assisted crown lengthening surgery accuracy (trueness ±precision) of gingivectomy (0.23 ±0.08 mm) was significantly higher than that of alveolectomy (0.33 ±0.11 mm) (P