We developed a jaw movement training robot system implementing a 6-degree of freedom (DOF) parallel mechanism, and applied it to jaw opening and closing training, which is one of the therapies for temporomandibular joint disorders. As one application of this system, we developed an intermaxillary traction therapy system that provides non-physiological movements, whereby the patients' jaws receive traction to regenerate healthy temporomandibular joint tissue. This therapy is especially effective for patients with a symptom called "open bite", i.e. those who cannot completely close their jaws. Additionally, the previously developed mastication robot was applied to this robot system as a patient model, and the training movements of the training robot were evaluated.

This paper describes a jaw movement training robot system implementing a 6 degrees of freedom (DOF) parallel mechanism, and its application for lateral movement raining. Temporomandibular joints (TMJ) problem is a disorder, whereby patients are not able to open their mouths nor move their jaws easily because of the problems with the mandibular joints, mastication muscles, and other organs concerning food chewing. Conventional therapy has been done with simple mouth opening apparatuses based on a doctor's technique through their own experiences, while this is still common. The authors have developed and improved a jaw movement training robot system, which provides not only jaw open and close training but also consists of a 6-DOF slave manipulator as a patient working manipulator and a 3-DOF master manipulator as a doctor commanding manipulator.

Conventional medical/dental systems have developed only doctor or patient models. However, two models are needed to quantify the dental/medical therapy; these are the patient model and the doctor model. The authors focus on the mouth opening and closing training done for the patients who have disorders on their jaw joints. The mastication robot as a patient model and the mouth opening-closing training robot as a doctor model are developed. The paper describes two robots that quantitatively evaluate the mouth opening and closing training. Force data using these two robots showed that robot training's force acting on the patient is smaller than the conventional training using a wooden device.

This paper describes the 6-degrees of freedom (6-DOF) jaw training robot that manipulates the patient's jaw to move sideway. Patients with jaw disorders who can not only control the opening/closing of their jaws, but also sideway movements are the target of this research. The authors developed a 6-DOF slave manipulator and 3-DOF master manipulator for these patients. The natural jaw's sideway motion was simulated by changing the center of rotation according to the rotational direction of the mandible. A real training for a jaw disorder patient using the robot was done, and the resulting distance to sideway was increased 9 to 15 mm in the right jaw joint and 7 to 12 mm in the left.

Describes a skull robot as a patient simulator for mouth opening and closing training. The rehabilitation for patients who have problems on the jaw joint have been done primarily based on the doctor's qualitative experience and technique that is unknown to other people. The authors developed a skull robot WOJ-1R as a mechanical patient simulator This skull robot will be useful for the doctor to develop the strategy of training for the real human patient. Also, it will quantitatively clarify the effectiveness of the robots therapy compared with therapy by human. Experimental results of biting force comparison show that robot therapy force data acting on the skull robot was smaller than the conventional therapy by human.

This paper describes the remote training between Tokyo and Yamanashi with 6 degrees of freedom (DOF) parallel robot that is designed for the mouth-opening and -closing training. Remote training is useful for the patients who have difficulties to go to hospitals frequently. The authors have developed a master-slave training system using ISDN lines because ISDN is not difficult to come by in patients home. Mouth-opening and -closing training robot WY-5R (Waseda Yamanashi-5 Refined) realized the remote training via two ISDN lines with 128 kbps. As a result of remote therapy using WY-5R, two patients' mouth-opening and -forward distances increased.

This paper describes a 6 degrees freedom (DOF) parallel robot that is designed for the mouth opening and closing training. The rehabilitation for the patient who have problems on the jaw joint, mastication muscles, and other organs concerning the food chewing have been done primarily based on the doctor's technique. Conventional mouth opening apparatuses (such as wooden screws, bite blocks and clothespins-type apparatus) only increases mouth opening distance and do not have actuators, sensors, and/or control systems. Moreover, during therapy, the quantitative force data is unknown in spite of its importance for the standardization of mouth opening and closing training. Mouth opening and closing training robot WY-5 (Waseda Yamanashi No. 5) consists of mechanical, actuation, sensor and control systems. As a result of therapy using WY-5, the mouth opening distance increased.

Describes remote training with a 6-degrees-of-freedom (DOF) parallel robot that is designed for training patients in mouth opening and closing. Rehabilitation for patients who have problems with their jaw joint, mastication muscles or other organs concerned with chewing food has been done primarily based on their doctor's qualitative experience and technique. Conventional mouth-opening apparatus (such as wooden screws, bite blocks and clothes-pin-type apparatus) only increases the mouth-opening distance and does not have any actuators, sensors and/or control systems. Moreover, during therapy, the quantitative data is unknown, inspite of its importance for the standardization of mouth-opening/closing training. The mouth-opening/closing training robot WY-5R (Wadaseda Yamanashi-5 Refined) realized the remote training via an ISDN line. As a result of remote therapy using WY-5R, the patient's mouth-opening distance increased.

Describes the development of a mouth-opening and -closing training robot WY-3 (Waseda Yamanashi-3) that has been designed and developed by combining oral-maxillofacial surgery and robotics. Mouth-opening training is useful for the rehabilitation of patients who have problems opening and closing their mouths. Conventional mouth-opening apparatus (such as wooden screws, bite blocks and clothespins type apparatus) only increase mouth-opening distance and do not have actuators, sensors, and/or control systems. Moreover, during therapy the quantitative force data is unknown in spite of its importance for the standardization of mouth-opening and -closing training. The mouth-opening and -closing training robot WY-3 consists of mechanical, actuation, sensor, and control systems. As a result of therapy using WY-3, the mouth-opening distance increased from 36 to 41 mm.

This paper describes the quantification of masticatory efficiency by using a mastication robot that was developed as a mechanical simulator of human masticatory jaw motion on the basis of dental robotics. The masticatory efficiency is evaluated on the basis of human mastication and the quantification of masticatory efficiency is studied experimentally. In this paper, the authors use the sifting test to quantify efficiency. The results of chewing experiments with robot by comparing the differences in chewing motion between clenching and grinding showed that the masticatory efficiency of the latter was higher than that of the former.