Toyohiko Hayashi

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Present dental CAD systems enable us to design functional occlusal tooth surfaces which harmonize with the patient's stomatognathic function. In order to avoid occlusal interferences during tooth excursions, currently available systems usually use the patient's functional occlusal impressions for the design of occlusal contact points. Previous(More)
Dysphagia (difficulty in swallowing) is an important issue in the elderly because it causes aspiration pneumonia, which is the second largest cause of death in this group. It also causes decline in activities of daily living and quality of life. The oral phase of swallowing has been neglected, despite its importance in the evaluation of dysphagia, because(More)
BACKGROUND In modern total knee arthroplasty (TKA), it is important to reproduce both medial pivot motion and posterior femoral rollback to obtain greater postoperative knee flexion. Several studies have reported the factors affecting knee motion and range of motion after TKA. The purpose of this study was to evaluate the effect of the tibial insert(More)
A photostereometric technology-based knee motion analysis system was developed and intraoperative kinematics during total knee arthroplasty (TKA) was investigated. Ten knees were evaluated and two different types of posterior-cruciate-retaining TKA (Genesis-I and Genesis-II) were used. Both TKA showed posterior translation of the medial and lateral femoral(More)
It has been reported that swallowing is a rhythmic movement, in which the onset of the oro-pharyngeal stage of swallowing starts from the mylohyoid muscle, followed by movement of the oral and pharyngeal muscles, and reaching the superior esophageal sphincter muscle. This is defined as the oro-pharyngeal stage of swallowing. It has also been reported that(More)
PURPOSE The aim of this study was to develop a means of coordinating helical computed tomography (CT)- based morphological data in 3 dimensions (3-D) with that pertaining to jaw movement as recorded by a device that measures jaw movement in six-degrees-of-freedom (6-DOF), thus producing multi-point movement analysis of the condyle. METHODS The study(More)
1 This open-access article is published and distributed under the Creative Commons Attribution-NonCommercial-No Derivatives License which permits the noncommercial use, distribution, and reproduction of the article in any medium, provided the original author and source are credited. You may not alter, transform, or build upon this article without the(More)
PURPOSE The purpose of this study was to develop a new device to measure continuously the vertical dimension of the human jaw relation using magnetic sensors. METHODS A sensor unit was made of six MI (Magneto-Impedance) sensors (AMI302 4.0 x 3.5 x 1.4 mm, Aichi Steel Corp.) placed in a line at intervals of 4 mm. The unit was positioned to the head by a(More)