High-precision all-in-one dual robotic arm strategy in oral implant surgery

Dental implantation, a highly effective tooth replacement method, significantly improves oral function and aesthetics compared to traditional dentures. Precise implant placement—considering position, angle, and depth—is critical for long-term success, demanding high-precision surgical techniques. Robotic surgery offers advantages such as increased precision, efficiency, minimally invasive procedures, and enhanced safety in various fields, including laparoscopic surgery, tumor ablation, and assistive robotics. In dental implantology, robot-assisted surgery is gaining traction, promising more accurate implant placement and minimizing risks. Existing methods, including static guidance and dynamic navigation, each have limitations. Static guidance, while simple and cost-effective, lacks real-time adjustability, making it vulnerable to patient movement. Dynamic navigation, although more precise and adaptable, increases costs. Previous research, such as that by Chiu et al. (2006), Kramer et al. (2005), Brief et al. (2005), and Casap et al. (2004), reported angle deviations around 4° in dynamic navigation systems. While advancements have been made (Boesecke et al., 2001; Sun et al., 2014; Yu et al., 2015; Zhao, 2017), challenges remain in terms of preoperative preparation time, occlusion handling, and overall system complexity. This paper proposes a novel dual-arm robotic system (HADAROIS) to address these challenges.

Existing literature extensively covers osseointegrated implants and their significance in restoring oral function. Studies compare various surgical techniques, highlighting the importance of implant stability and accurate placement. The application of robotics in medical procedures is well-documented, demonstrating its potential in improving precision and efficiency. The application of robots to dental implantology has seen growth, with notable contributions exploring robot-assisted implant placement (Boesecke et al., 2001; Sun et al., 2014), image-guided navigation systems (Yu et al., 2015), and autonomous systems (Zhao, 2017). However, these methods often face challenges such as extended preoperative preparation times due to coordinate registration needs, limited adaptability to dynamic changes during surgery, and susceptibility to occlusion issues in image-based navigation. Existing systems, like the Yomi system, represent advancements but come with high costs and the need for specialized skills.

The proposed HADAROIS system integrates dual robotic arms: one manipulating surgical tools and the other carrying a miniature multi-eye gaze positioning camera. This all-in-one design significantly reduces preoperative preparation time by eliminating the need for separate calibration of the arms and optical positioning camera. The system utilizes three key modules: 1. **Occluded Target Tracking Module (OTTM):** This module uses image-guided techniques to track the target position in real-time, even when occluded by anatomical structures or instruments. The system employs a novel miniature camera with high accuracy (0.05 mm) and refresh rate (>100 Hz). It dynamically adjusts the camera's position and orientation to maintain unobstructed tracking. A lookup area is created around the target, and the camera searches within this area for an optimal viewing angle that captures all marker points. 2. **Planting Plan Development Module (PPDM):** This module utilizes CBCT data to create an implant plan. It extracts and analyzes tissue information to identify tissue boundaries and determine the optimal implant direction and position (starting and ending points). The system visualizes this plan to the surgeon for intuitive planning. 3. **Path Formulation Module (PFM):** This module coordinates the movement of both robotic arms in real-time. It transforms the target position from the camera's coordinate system to the surgical arm's coordinate system. It plans the trajectory for the surgical arm, ensuring collision avoidance and smooth movement. A reference device is used to track patient head movement, maintaining accuracy. The system provides real-time feedback on the position and orientation of the surgical tools. The Universal Robots 3 manipulators and NDI's Polaris Vicra optical tracker were selected for their precision and compact design. The complete surgical workflow includes preoperative CBCT scanning, registration, implant plan generation using PPDM, real-time tracking using OTTM, and coordinated robotic arm movement using PFM. The system's interface facilitates intuitive surgical plan selection and monitoring.

Simulation experiments using 5 dental models (10 experiments total) yielded an average angular deviation of 1.54° (SD 0.67°) and an average entry-point deviation of 0.334 mm (SD 0.202 mm), demonstrating the system's accuracy and repeatability. Clinical trials involving five patients yielded an average angular deviation of 2.1° and an average entry-point deviation of 0.39 mm. These results were compared to previous studies, highlighting the superior accuracy of the HADAROIS system. The study demonstrated that the HADAROIS system is a reliable tool for accurate implant placement, with deviations well within the clinically acceptable range. The postoperative analysis (Table 2) shows that even with larger angular deviations, the shoulder-to-root deviations remain within the safe 2mm limit. A visual representation of the angle and entry-point deviation for a particular patient is also provided (Fig. 9).

The HADAROIS system addresses key limitations of existing robotic oral implant systems. Its all-in-one design reduces the surgical preparation time significantly. The integrated modules (OTTM, PPDM, and PFM) streamline the surgical process, improving efficiency, safety, and reducing the dependence on surgeon experience through automated planning and real-time obstacle avoidance. The system's high accuracy, demonstrated in both simulation and clinical trials, significantly improves the precision of implant placement, leading to better long-term outcomes for patients. The system's introduction into clinical practice has already received positive feedback, underscoring its practical application and potential to enhance the field of dental implantology.

The HADAROIS system presents a significant advancement in robotic oral implant surgery. The integrated dual-arm design and the sophisticated control modules improve precision, efficiency, and safety. The superior accuracy demonstrated in both simulated and clinical settings confirms the system's effectiveness. Future work could focus on further enhancing the system's adaptability to various anatomical structures, expanding its capabilities to handle more complex implant cases, and developing more intuitive user interfaces.

The study's sample size was relatively small. Further clinical trials with a larger and more diverse patient population are needed to validate the system's generalizability. While the system effectively addresses occlusion, extremely challenging anatomical cases or unexpected surgical events may still require surgeon intervention. Long-term follow-up studies are needed to evaluate the long-term success rates of implants placed using HADAROIS.