Development and Evaluation of an Automated Robotic System for Full Crown Preparation

Objectives: To develop a robotic system for full crown tooth preparation and to evaluate its preparation accuracy and operation time. Methods: The robotic system comprised a robotic arm, an infrared optical tracking system, and proprietary planning/control software. The planning workflow encompassed path planning for axial and occlusal surfaces, functional cusp bevels, and acute line angles, culminating in the generation of an ideal preparation morphology. Twenty-two standardized partial dentition models of mandibular teeth 35–37 were additively manufactured and equally allocated into two experimental groups based on preparation methodology: an automated robotic system group and a step-by-step guide group. Operation time was recorded concurrently. Post-preparation scan data were imported into three-dimensional reverse engineering software to calculate the root-mean-square-error (RMSE) values for the overall surfaces, axial surfaces, occlusal surfaces, and chamfer regions to evaluate preparation accuracy. Results: In the posterior crown preparation model experiment, the robotic group showed significantly lower RMSE values than the guide group overall and by region: overall, 0.18±0.03 vs 0.33±0.05 mm; axial, 0.15±0.06 vs 0.27±0.08 mm; occlusal, 0.20±0.05 vs 0.38±0.07 mm; chamfer, 0.12±0.03 vs 0.30±0.07 mm. The occlusal surface yielded the lowest accuracy in both groups. The robotic system also significantly reduced preparation time (350.15±7.79 s vs. 583.93±90.48 s), confirming its efficiency advantage. Conclusions: This study developed an automated robotic system for crown preparation that demonstrated superior accuracy and shorter operation time compared with the guide approach. Clinical significance: In this study, we developed a novel robotic system for full crown preparation that may enable precise and efficient procedures, representing a promising approach for achieving high-accuracy tooth preparation while minimizing tissue removal.