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Biomedical subjects

H Tsuru

Publications and source records attributed to H Tsuru.

At least 73 records · Page 4Linked to original sources
PubMed1989

Correlation between clinical and histological evaluations of the peri-implant gingiva around the single-crystal sapphire endosseous implant.

The correlation between clinical periodontal parameters and histological structure of the gingiva around a single-crystal sapphire implant has been evaluated in two volunteer subjects. The implants had functioned after 6 years as the distal abutment of implant bridges in the Kennedy class II mandible. First, clinical evaluation was performed (gingival bleeding index, crevicular fluid volume, plaque index and probing depth) of the gingiva around the implant and natural teeth abutments and then a small piece of peri-implant gingiva was excised from the lingual site of the implant of each subject for histological evaluation. The clinical evaluation using the periodontal parameter indices corresponded with the histological evaluation of the peri-implant gingiva. The result suggests that it is possible for such parameters to be used in practice for judging the success of an implant.

Adult↗
PubMed1989

Heterogeneity of beta-adrenoceptor in canine veins: comparison among the facial, portal and saphenous veins.

A study was made on the characteristics of beta-adrenoceptors in the isolated canine facial, portal and saphenous veins. Ring segments of the facial and saphenous veins and longitudinal strips of the portal vein were suspended in tissue baths containing Krebs solution oxygenated and maintained at 37 degrees C. They were moderately contracted with prostaglandin F2 alpha before examining their relaxation responses. The facial and saphenous veins fully relaxed to isoproterenol, while the portal vein relaxed to a small extent (20% of maximum relaxation) even in the presence of an alpha-adrenoceptor blockade. In contrast, both forskolin, a direct activator of adenylate cyclase, and membrane-permeable dibutyryl cyclic AMP similarly relaxed all the veins studied. Thus, the reduction of coupling between beta-adrenoceptors and the adenylate cyclase system may be involved in the decreased responsiveness of the portal vein to beta-adrenoceptor agonists. In addition, analyses of beta-adrenoceptor agonism and antagonism, using selective (beta 1: T-1583, beta 2: procaterol) and non-selective (isoproterenol) agonists as well as selective (beta 1: atenolol, beta 2: ICI 118,551) and non-selective (propranolol) antagonists, confirmed that beta-adrenoceptors in the canine facial vein are not homogeneous, with the beta 1-subtype predominating over the beta 2-subtype, and that the canine saphenous vein has a homogeneous population of the beta 2-subtype, as reported in the other species.

Adenylyl Cyclases↗
PubMed1989

[Electromyographic study on masticatory function of the telescope denture wearers in the Kennedy Class II mandible].

Masticatory function of 10 telescope denture wearers in the Kennedy class II mandible patients was evaluated with electromyography. Electromyographic activity during mastication with kamaboko and peeled raw carrot was recorded from bilateral masseter and the anterior part of temporal muscles at each interval: Before treatment, immediately after denture insertion and 2, 4, 6, 8 weeks after respectively. Mean of duration, interval and cycle of EMG activities, coefficient of variation and average variation were calculated. The results were as follows: 1. Means of duration and cycle times decreased immediately to 2 weeks after denture insertion. 2. EMG activities during raw carrot chewing became regular immediately to 2 weeks after denture insertion, and within 4 weeks in kamaboko chewing. These results suggest that telescope dentures would be adapted to stomatognathic system within short period after denture insertion.

Denture, Overlay↗
PubMed1989

Clinical evaluation of a new resilient denture liner in long-term use.

The new resilient denture liner "M" was evaluated for adhesion, color stability, surface texture, tissue response, deterioration and denture base stability, at periods of 1 month, 3 months and about 30 months after denture liner application. At the observation of approximately 30 months, the usage of 17 dentures had been discontinued within 2 years, and 6 dentures continued to be used. It could be considered that the main reasons why 17 dentures were discontinued were poor fitting caused by deterioration, and a decrease in the strength of the denture base caused by the denture liner lining. It was suggested that "M" was appropriate for long-term use (about 2 to 3 years), if patients faithfully practice denture cleaning, and if the strength of denture base is considered.

Adult↗
PubMed1989

Accurate evaluation of balancing-side contacts in relation to internal derangements of the temporomandibular joint: possible roles of balancing-side protection.

Balancing-side contacts were precisely evaluated in relation to internal derangements of the temporomandibular joint. Balancing-side contacts were classified into the three following groups: 1) Severe balancing-side interference, 2) balancing-side interference and 3) balancing-side protective contacts. Balancing-side protective contacts were defined as balancing-side occlusal contacts on lower first and/or second molar in lateral excursive movements, which are observed only when clenching forces are exerted. The prevalence of the balancing-side protection was revealed to be highly correlated with that of internal derangements of temporomandibular joint. These results strongly suggest that balancing-side protection might play an important role as a regulating mechanism in the etiology of internal derangements of temporomandibular joint.

Adult↗
PubMed1989

Comparative evaluation of chewing function with removable partial dentures and fixed prostheses supported by the single-crystal sapphire implant in the Kennedy Class II partially edentulous mandible.

Differential chewing function with removable partial dentures (RPDs) and fixed prostheses supported by the single-crystal sapphire implant was evaluated in five subjects with Kennedy Class II partially edentulous mandibles by means of electromyography. Rehabilitation with the single-crystal sapphire implant resulted in regular chewing patterns with a low variation coefficient and higher activity of chewing-side masticatory muscles compared to RPD rehabilitation. This difference in chewing function between the two rehabilitation modalities could be the result of differences in stability of occlusion and neurophysiologic feedback systems.

Aluminum Oxide↗
PubMed1988

Morphology of single mesencephalic trigeminal neurons innervating masseter muscle of the cat.

The morphology of functionally identified single axons of mesencephalic trigeminal neurons was studied in the cat by the method of intra-axonal injection of horseradish peroxidase (HRP). Each axon can be divided into united (U), peripheral (P) and central branches (C). The united axon (U) descends from its soma within the tract of the trigeminal mesencephalic nucleus to the dorsal aspect of the trigeminal motor nucleus (Vmo), where it splits into peripheral and descending central branches with a Y-shaped bifurcation. The peripheral axon (P) joins the motor root of the trigeminal nerve to exit the brainstem. The central axon (C) travels caudally within the juxtatrigeminal regions (or lateral reticular formation). All 3 branches issue axon collaterals that distribute terminal boutons within the dorsolateral subdivision of Vmo, supra- and intertrigeminal regions. Collaterals emanating from the central axon (C) except for its proximal segment travel ventrolaterally within the juxtatrigeminal regions, and send their terminal branches into the lateral boundaries adjacent to the spinal trigeminal nucleus. The trajectory of terminal branches distinguishes group Ia afferents from the possible group II afferents. The majority of terminal boutons are found to distribute in the supra- and intertrigeminal regions for group II afferent fibers and in the dorsolateral subdivision of Vmo for group Ia afferents.

Afferent Pathways↗
PubMed1988

Bone-implant interface structures after nontapping and tapping insertion of screw-type titanium alloy endosseous implants.

To compare different surgical insertion procedures, histologic and histometric studies were made on the structure of the interface between jaw bone and implants in two monkeys. Two materials were tested; TiO2 coated and noncoated, screw-type titanium alloy endosseous implants. All implants by tapping insertion were healed with direct bone apposition whereas implants by nontapping insertion revealed some degrees of fibrous connective tissue intervention between bone and implant. No difference was found between TiO2 coated and non-coated materials.

Alloys↗
PubMed1988

Single-crystal sapphire endosseous dental implant loaded with functional stress--clinical and histological evaluation of peri-implant tissues.

Peri-implant tissues of the single-crystal sapphire implant connected with neighbouring teeth by a metal bridge-work were examined clinically, radiographically, and histologically in ten monkeys. Professional tooth cleaning was performed during the study. At 3-12 months after insertion, most of the implants were firmly connected to the surrounding tissues and peri-implant gingiva was regarded as healthy, based on various periodontal parameter scores. Destructive changes of the peri-implant bone were not found radiographically. Histologically, peri-implant gingiva was revealed to show similar structure to that of the gingiva around natural teeth. Direct bone-implant interface was observed at 3 months after insertion, while a thin loose fibrous connective tissue layer was present between bone and implant at 6 and 12 months. Such different interrelationship between bone and implant might be attributable to the difference in distribution of functional stress.

Aluminum↗
PubMed1988

A new objective parameter for the electromyographic evaluation of masticatory function of edentulous patients.

An objective parameter for the electromyographic evaluation of the masticatory function of edentulous patients was studied. The normal ranges of the parameters for such subjects were also established. This study focused on the time parameter of electromyography, which is one of the most reproducible parameters. The variation coefficient of the time parameters (interval and duration) were revealed to be reliable and reproducible for the evaluation of masticatory functions.

Aged↗
PubMed1988

Tissue response to implanted ceramic-coated titanium alloys in rats.

In order to assess the tissue compatibility of the hybrid materials for the dental implant (hydroxyapatite, titanium oxide and titanium nitride coated titanium alloys), tissue response to these materials implanted in the rat subcutaneous tissue was histologically examined. Initial inflammatory response was less evident in titanium oxide coated and non-coated titanium alloys. All materials were encapsulated by thin fibrous connective tissues. The membrane thickness of hydroxyapatite coated titanium alloy was significantly higher than that of titanium nitride coated one. These results suggest that all materials possess favourable tissue compatibility and may encourage clinical use as the dental implant.

Alloys↗
PubMed1988

A criterion for the selection of artificial posterior teeth.

Mandibular movement and masticatory performance were evaluated in the edentulous patients with an experimental denture using posterior artificial teeth of different occlusal schemes in order to determine the criterion for the selection of posterior artificial teeth. Lower masticatory performance was observed with non-anatomic posterior teeth than with semi-anatomic or anatomic ones regardless of the condition of residual ridge and inclination of the horizontal condylar guidance. The value of the lateral component of the masticatory cycle was closely related to the inclination of the cusp and the value of masticatory performance. This suggested strongly that the component could be a criteria for the selection of the type of the artificial posterior teeth.

Aged↗