Masatoshi Ohnishi

Mouth opening and closing training with 6-DOF parallel robot

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 doctors 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.

Quantification of masticatory efficiency with a mastication robot

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.

Integrated dental robot system for mouth opening and closing training

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 trainings force acting on the patient is smaller than the conventional training using a wooden device.

Jaw training robot that manipulates patient's jaw to sideway

This paper describes the 6-degrees of freedom (6-DOF) jaw training robot that manipulates the patients 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 jaws 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.

Mechanisms of platelet retention in the collagen-coated-bead column.

Although the glass-bead column has been used to measure platelet adhesion, whether platelet interaction with glass beads represents physiologic processes remains unsettled. In an attempt to obtain more physiologic platelet responses, plastic beads coated with type I collagen have been recently developed to replace glass beads. In this study, we analyzed the factors responsible for platelet retention in the collagen-coated-bead column and investigated its possible clinical applications. We pumped citrated whole-blood samples into columns at a fixed speed with an injection pump and calculated platelet-retention rates by measuring platelet counts before and after passage through the columns. The platelet-retention rates, which were highly reproducible with samples from healthy donors, were reduced in a patient with glycoprotein (GP) VI deficiency but not in patients with type III von Willebrand disease. Anti-GPIIb/IIIa antibody and GRGDS peptide markedly inhibited platelet retention, whereas inhibition of the GPIb-von Willebrand factor or GPIa/IIa-collagen interaction had no effect. Data on the effects of various antiplatelet agents (including the antithrombin agent argatroban, prostacyclin, acetylsalicylic acid, and the ADP scavenger creatine phosphate/creatine phosphokinase) support the usefulness of this assay method in clinical application. Our findings suggest that GPVI and GPIIb/IIIa but not the GPIb-von Willebrand factor interaction are mainly involved in platelet retention in this column.

Remote therapy with mouth opening and closing training robot between Tokyo and Yamanashi 120 km

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.

Human skull robot as a mechanical patient simulator for mouth opening and closing training

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 doctors 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.

Universal Dental Robot — 6-DOF Mouth Opening and Closing Training Robot WY-5

This paper describes the mechanism, control method, and training results of the 6 degrees-of-freedom (DOF) mouth-opening and -closing training robot WY-5 (Waseda Yamanashi No. 5) that is an application of the Universal Dental Robot (UDR). The mouth-opening training is indicated for the rehabilitation of the patients suffering from disturbance of the mouth-opening and -closing. The six linear actuators manipulate the u-shaped end-effector of UDR. This u-shaped end-effector is a moving platform of 6-DOF parallel manipulator. Each linear actuator has displacement, velocity, and force sensor to measure the position and orientation of the u-shaped end-effector. The WY-5 is a master-slave parallel robot that manipulates the patient’s mandible that can’t widely open. The doctor grasps the 2-DOF master manipulator, and the 6-DOF slave manipulator opens the patient’s mandible according to the master manipulator’s motion. As the result of therapy by using WY-5 for two female patients who cannot open their mouth widely, the mouth opening distance increased.

Remote treatment with mouth opening and closing training robot

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 doctors 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 patients mouth-opening distance increased.

Three degrees of freedom mouth opening and closing training robot

Describes the mechanism and control of a three degrees of freedom (3-DOF) mouth-opening and -closing training robot WY-2 (Waseda Yamanashi-2). The WY-2 is a master-slave type 3-DOF robot. The WY-2 consists of a mechanical actuation sensor, and control systems. The seesaw mechanism inserted in the patients mouth opens the mouth by squeezing the master manipulator. The 6-axes force-moment sensor measures the patients biting force. A personal computer integrates and controls the other systems. As the result of therapy using WY-2, mouth-opening distance increased from 29 to 37 mm.