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Biomedical subjects

T Suetsugu

Publications and source records attributed to T Suetsugu.

At least 19 recordsLinked to original sources
PubMed1990

Two-dimensional FEM analysis of hydroxyapatite implants: diameter effects on stress distribution.

The effect of the diameter of hydroxyapatite (HAP) implants on stress distribution in alveolar bone was analyzed by two-dimensional finite element methods (FEM), with use of a 100-N vertical and lateral load. Since HAP is considered a bioactive material, the alveolar bone was assumed to be bonded directly to the HAP implant in the FEM model. The analysis showed that the stresses in cortical bone were generally higher than those in cancellous bone, and that the stress concentration occurred mainly in cortical bone around the neck of the implant with both vertical and lateral load. The stresses in cortical bone with lateral load were especially high-twice those in vertical load. Stresses in cortical bone decrease in inverse proportion to the increase in implant diameter with both vertical and lateral load. The results suggested that an implant with a large diameter is favorable from the standpoint of stress distribution.

Alveolar Process↗
PubMed1989

[Geometrical investigation on mechanism and movement of Gysi Simplex OU articulator].

Gysi Simplex OU articulator was constructed by modifying Gysi Simplex 1914, and has been used for students' practice of complete denture construction at 18 Japanese dental schools. Therefore, the mechanism and movement of the articulator should be explained and understood clearly from the educational standpoint of view. In this study, the movement was analyzed by geometrical drawing after Ishiwara-Suetsugu's simplified method. The following results were obtained: 1. Sagittal inclination of incisal guidance acted as an important role for location and inclination of lateral axis. 2. Accessory working condylar guide, which is located behind the condyle post, is another important mechanism as one of determinants of the movement. 3. The lateral wall of balancing condylar guide should be forced to touch always the balancing condyle. 4. It was clarified that the movement of Gysi Simplex OU followed the Gysi's axis theory.

Dental Articulators↗
PubMed1989

[Movement analysis of Gysi Simplex OU articulator. 1. Rotational point and lateral axis].

Several researches have been reported on the mechanism and movement of Gysi Simplex OU articulator. And it was clarified logically by geometrical drawing method that the movement of the articulator followed the Gysi's axis theory. But no study reported about the movement of the articulator by measuring it. Therefore, the authors measured the movement of the articulator with Kyushu University 3-D movement analyzing system, and compared it with the results obtained from geometrical drawing method which we reported previously. The following results were obtained: 1. The rotational point exists actually at the same position where we analyzed by geometrical drawing method. 2. Lateral axis is constructed by joining the rotational points at various height. 3. The inclination of lateral axis changes by sagittal inclination of incisal guidance. As the results, we clarified that the movement of Gysi Simplex OU followed the Gysi's axis theory.

Dental Articulators↗
PubMed1989

Quantitative study on the interface between bone tissue and Blade-vent implants using the image processing system.

Undecalcified histopathologic sections of two titanium blade-vent implants (which had survived for five years in a dog) were made, and image analyses of the bone-implant interface were determined. One implant was inserted conventionally in the right mandible, and the other was inserted shallower than usual in the left mandible, so that the shoulder was located at the same level as the residual bone ridge. Using an image analysis technique, we observed, on the deeper implant, a 0-56% rate of bony contact around the implant and a 71-84% rate of bone-vent occupancy in the vents. With the shallower implant, a 0-46% rate of bony contact and a 26-60% rate of bone-vent occupancy were observed. When the two implants were compared, the deeper implant showed relatively higher bony contact and bone-vent occupancy than its less-submerged control in the five-year study.

Animals↗
PubMed1989

Improved method using a bubble-free adhesion technique for the preparation of semi-serial undecalcified histologic sections containing dental implants.

The preparation technique, with the minimum of artifacts for the semi-serial undecalcified histologic sections containing dental implants, is presented in this study. The sections enabled finer light-microscopic observations to be made. A formalin-fixed tissue block containing a dental implant was dehydrated in ethanol and acetone, and then embedded in polyester resin under 76 cm Hg reduced pressure. The embedded block was trimmed by a cutter and ground by abrasive paper. In a 1.5 Kg f/cm2 pressurized chamber, its polished surface was bonded to a methacrylate slide by means of ethylcyanoacrylate used in an adhesion loading device. This meant that no bubbles could arise in the interface between the slide and the block. The slide-block was then attached to an adsorptive specimen-holder of a hard-tissue cutting machine and cut to a thickness of approximately 50 microns, with use of a diamond blade. The slide-section was ground to 15-40 microns with wet-type abrasive paper and film on a polishing table. Etching with weak acid and surface staining with toluidine blue and methylene blue/basic fuchsin/light green were performed on the section.

Acrylic Resins↗
PubMed1988

Differences between the bony interfaces of titanium and hydroxyapatite-alumina plasma-sprayed titanium blade implants.

Histopathologic study was done to reveal the difference of bony interface in the mandibular bone between titanium blade implants and titanium implants coated with the mixture of hydroxyapatite-alumina by the plasma-spray technique, using the improved undecalcified histologic technique and the image analyzing system. In 4 adult shepherd dogs, the implantation was performed in the molar region of the mandible 2 months after tooth extraction. The coated implants and the non-coated ones were inserted respectively in the mandibles. They were sacrificed on the 5th, 7th, 14th and 28th day postoperatively. In 5-day implant after insertion, granulation tissues or fibrous connective tissues were observed around both implants in bone tissues. In 7-day implant, osteoid tissues regenerated around the apex of both implants, but attached a little to them. In 14-day implant, osteoid tissues or woven bone regenerated around both implants and attached more to the coated implant (approximately 13.7%) than the non-coated one (approximately 6.0%). In 28-day implant, regenerative woven or lamellar bone attached much more to the coated implant (approximately 63.4%) than the non-coated one (approximately 8.8%). Bony interface increased remarkably in the coated implants, chronologically. The results showed that the plasma-sprayed hydroxyapatite-alumina coating was effective for the initial fixation of endosseous dental implants.

Aluminum Oxide↗
PubMed1987

Prenatal developmental process of human temporomandibular joint.

The prenatal development of 20 human TMJs from the fourteenth gestational week to full term was studied and the following observations were made. Radiologic findings: at the sixteenth gestational week, the outline of the TMJ as radioopaque structures appeared. Curvature of the articular eminence of the temporal components was observed at gestational week 33, and convexity of the condylar head of the condylar process was observed at the thirty-first week. Histologic findings: at the fifteenth gestational week, thin intramembranous ossification of the temporal components and endochondral ossification of the condylar process were observed, and secondary cartilage occupied the whole condylar process. The articular disk was distinguishable and was composed of fine collagen fibers. At the seventeenth gestational week, endochondral ossification of the condylar process appeared, the formation of joint cavities was fairly completed, and synovial tissues were easily observed. From gestational week 17 through 21, endochondral ossification of the condylar process developed rapidly and the layer structures, which consisted of a fibrous covering layer, transitional cell layer, hypertrophic layer, and erosive layer, were observed. At the twenty-first gestational week, Meckel's cartilage disappeared and hematopoietic foci appeared in the temporal components and the condylar process. Week 21 seemed to be the greatest turning point of the prenatal development of the human TMJ. Secondary cartilage of the condylar process diminished gradually throughout fetal life, but was vestigial at full term.(ABSTRACT TRUNCATED AT 250 WORDS)

Cartilage, Articular↗
PubMed1987

Clinico-pathological study on denture stomatitis.

The clinical and pathological study was performed in order to determine the histopathological and cytoimmunological characteristics of denture stomatitis. All specimens were biopsy materials from seventeen patients with denture stomatitis. Normal palatal mucosae from ten patients served as the control. In addition to the usual staining methods, naphtol AS-D chloroacetate esterase stain and peroxidase-antiperoxidase method were used to detect mast cells and plasma cells. Denture stomatitis could be divided into atrophic and hyperplastic types. The former showed a smooth and atrophic mucosa. The latter showed a large number of exophytic projections which were composed of marked acanthosis and submucosal fibrosis, and was further subdivided into granular and papillary subtype according to the size of projections. In the present study, there were six cases of the atrophic type, and eleven cases of the hyperplastic type (consisting of seven granular and four papillary subtypes). The hyperplastic type was more frequently observed in patients with partial dentures compared with complete dentures and was associated frequently with ill fitting of the denture base as well as agglutination of denture plaque. Cytoimmunological study revealed that there was a pronounced increase of plasma cells, especially IgG- and IgA-producing cells, and a moderate increase of lymphocytes as well as mast cells in both types of denture stomatitis. Mast cells were always noted in the area with marked plasma cell infiltration, suggesting an intimate relation between both cells. These findings suggest that the immunological reactions play some role in the pathogenesis of denture stomatitis.

Adolescent↗