Establishment and evaluation of path planning strategy and execution methods for posterior tooth preparation using an autonomous oral surgical robot

Objective To establish two path-planning strategies and execution modes for posterior tooth preparation and to evaluate their feasibility preparation accuracy, and efficiency using an autonomous oral surgical robot, so as to provide a reference for the clinical application of autonomous oral surgical robots in tooth preparation. Methods Twenty three-dimensinal (3D)-printed resin standard mandibular partial dentition models (teeth 35-37) were allocated to an experimental group (n=10) and a control group (n=10). A full-crown preparation path-planning strategy for tooth 36 was established in the software. The experimental group adopted a feature-guided stepwise removal preparation strategy, whereas the control group adopted an equal-section layered milling preparation strategy. The robot performed tooth preparation on the 3D-printed resin standard mandibular partial dentition models fixed on the experimental bench, and the preparation time was recorded. After preparation, the models were three-dimensionally scanned and registered to the ideal prepared tooth model planned in the software. A 3D comparison between the actual prepared tooth and the planned preparation was performed to assess 3D deviation and the percentage of the actual removed volume (the designed value was 37.3%). Results Robotic tooth preparation was successfully completed for all models in both groups. The 3D deviation in the experimental group was (0.13±0.02) mm, significantly smaller than that in the control group (0.80±0.04) mm (t=47.37, P<0.05). With an identical designed removal amount of 37.3%, the actual removed volume percentage in the experimental group [(39.32±1.18)%] was closer to the designed value and significantly higher than that in the control group [(23.86±1.92)%] (t=21.70, P<0.05). The preparation time was (350.6±7.5) s in the experimental group, which was significantly shorter than that in the control group [(1 390.6±47.5) s] (t=68.34, P<0.05). Conclusions Using an autonomous oral surgical robot, posterior tooth preparation could be completed with both path-planning strategies and execution modes. However, the feature-guided stepwise removal preparation strategy was superior to the equal-section layered milling preparation strategy in both preparation accuracy and efficiency.