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The results of oral and maxillofacial surgery (OMS) significantly depend on the individual capabilities of surgeons. In this article, an autonomous surgical robot is proposed to automatically perform surgery according to a preoperative plan with the assistance of a surgeon. A 3-D computed tomography image of the subject's teeth was used to build an offline shape-based model by creating a large amount of 2-D contour data. A monochrome camera was mounted on a self-developed robot to capture the real-time image of the teeth for comparison with the offline 2-D contour to verify the teeth pose without using common markers. The data of the preoperative plan and the teeth pose were integrated to guide the movement of the robot during operation. Drilling experiments were conducted on the five 3D-printed mandible models, and a statistical analysis revealed highly accurate results. This autonomous robot provides a practical solution for robotically conducted OMS and has the potential to significantly reduce the workload of surgeons.

Impracticable workspaces and cumbersome hardware limit the practical application of the currently available orthognathic surgical robots in a clinical environment. In this study, a compact and lightweight six degree of freedom (DOF) robot with a workspace limitation mechanism (WLM) was developed, and this article reports on the technical specifications of the robot, as well as the details of the three experiments performed to validate it. This robot can be easily installed by a single individual and is able to mechanically protect important organs from unintended injury. The results show that this robot functionally limits the workspace travel of the osteotomy device by an average overshoot of 0.8 mm, with a drilling and cutting accuracy of 1 and 0.5 mm, respectively. This operational accuracy has the potential to be further improved, making this novel robot a potentially precise and safe medical equipment for orthognathic surgery.

Computer-assisted oral and maxillofacial surgery (OMS) has been rapidly evolving since the last decade. State-of-the-art surgical navigation in OMS still suffers from bulky tracking sensors, troublesome image registration procedures, patient movement, loss of depth perception in visual guidance, and low navigation accuracy. We present an augmented reality navigation system with automatic marker-free image registration using 3-D image overlay and stereo tracking for dental surgery. A customized stereo camera is designed to track both the patient and instrument. Image registration is performed by patient tracking and real-time 3-D contour matching, without requiring any fiducial and reference markers. Real-time autostereoscopic 3-D imaging is implemented with the help of a consumer-level graphics processing unit. The resulting 3-D image of the patient's anatomy is overlaid on the surgical site by a half-silvered mirror using image registration and IP-camera registration to guide the surgeon by exposing hidden critical structures. The 3-D image of the surgical instrument is also overlaid over the real one for an augmented display. The 3-D images present both stereo and motion parallax from which depth perception can be obtained. Experiments were performed to evaluate various aspects of the system; the overall image overlay error of the proposed system was 0.71 mm.

Noncontact operation of a cycloid motor by means of a magnetic force has been realized. The fabricated motor has a cycloid reduction system with an internal gear as a stator and an external gear as a rotor. A cylindrical permanent magnet encloses the internal gear. The internal gear generates a wobbling motion due to attractive and repulsive magnetic forces produced by external permanent magnets. An output shaft attached to an external gear is rotated by the wobbling motion of the internal stator gear. This motor can be operated by means of magnetic fields applied to one side of the device. This feature allows the device to be used in medical procedures such as bone distraction osteogenesis, in which the actuator must be inside the human body for a long period of time. Such noncontact operation of the actuator reduces the burden on the patient. The fabricated motor exhibited a maximum torque of 4.1 mN·m and a maximum linear output of 4.9 N using a screw-nut system when the gap between the outer magnets and the motor was 2mm.