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Y Tsuchitani

Publications and source records attributed to Y Tsuchitani.

49 records · Page 3Linked to original sources
PubMed1981

Adherence of Streptococcus sanguis clinical isolates to smooth surfaces and interactions of the isolates with Streptococcus mutans glucosyltransferase.

Streptococcus sanguis isolated from human dental plaque were grown in Todd-Hewitt broth. Cells were collected by centrifugation and lyophilized after extensive washing with water. The cell-associated glucosyltransferase (GTase) activities of S. sanguis strains were assayed with [14C]sucrose. Strain differences in GTase activity were significant within the same serotype or biotype or both. The ability of S. sanguis cells to adhere to smooth glass surfaces was generally weak, irrespective of significant cell-associated GTase activity synthesizing water-insoluble, gel-like glucans. Resting cells of most S. sanguis strains bound extracellular GTase from Streptococcus mutans strain B13 (serotype d), resulting in the strong adherence of the S. sanguis cells to smooth glass surfaces in the presence of sucrose. Conversely, S. mutans B13 cells also could bind extracellular GTase from some strains of S. sanguis examined. The sucrose-dependent adherence of S. mutans cells was not altered, although S. sanguis strains from which the extracellular GTases were obtained did not produce significant adherence in the presence of sucrose. In view of these findings, it was suggested that S. mutans GTase could affect the adherence of S. sanguis to smooth tooth surfaces in the oral cavity.

Binding Sites↗
PubMed1980

Isolation and immunobiological classification of Streptococcus sanguis from human tooth surfaces.

A total of 113 pure cultures of Streptococcus sanguis were obtained from dental plaque samples of 64 subjects. All isolates synthesized glucan from sucrose, elaborated peroxide, and were alpha-hemolytic. Two biotypes and four serotypes were differentiated within the species. Biotype A (95 isolates) fermented salicin and inulin and hydrolyzed arginine and esculin, whereas biotype B (18 isolates) did not possess these activities. The isolates were serotyped with autoclaved extracts against whole-cell antiserum to strains ATCC 10556 or ST3 (serotype I), ATCC 10557 (serotype II), ATCC 10558 (serotype III), and ST7 (serotype IV), by the capillary precipitin test. Serotypes I, II, III, and IV were found to consist of 24, 16, 37, and 15 isolates. Type IV was demonstrated anew in this study. The remaining 21 isolates were not typed because of either multiple reactions or nonreactivity against the standardized typing sera. All isolates of serotype II belonged to biotype B, which resembles Streptococcus mitior physiologically. Five isolates representing four serotypes and an untypable strain were examined for their cariogenicity against specific-pathogen-free Sprague-Dawley rats fed high sucrose diet no. 2000. Organisms of each isolate were established in the mouths of the rats, but only three isolates induced weak caries that were restricted to pits and fissures of occlusal surfaces of the teeth.

Adolescent↗
PubMedDate not supplied

Eight-year clinical evaluation of fired ceramic inlays.

This study evaluated the quality of fired ceramic inlay restorations consisting of a feldspathic porcelain system (G-Cera Cosmotech II, GC Co, Tokyo, Japan) after eight years in vivo. Forty-five fired ceramic inlays (for 26 premolars and 19 molars; Class I in 12 teeth, Class II in 31 teeth and onlay in two teeth) were placed in 25 patients. All restorations were evaluated at the time of placement and at 6 months, 1, 2, 4, 6 and 8 years after placement using modified USPHS criteria. Replicas of the restorations were observed with a scanning electron microscope (SEM) to evaluate the degradation of the marginal area and wear loss of the restoration. Longevity was observed in 80% of the fired ceramic inlay restorations at eight years (Kaplan-Meier method), although it was 92% at the six-year observation. Marginal fracture was detected in 11 restorations (22%), including bulk fracture in five (11%), which had first occurred during the last two years. Recurrent caries was observed in three (7%) cases and marginal discoloration in 14 (31%). SEM evaluation disclosed marginal microfractures in 77% of the restorations, wear in 36% and wear of the resin cement along the margin in 74% at eight years. No significant difference was observed in each of these three characteristics between molars and premolars. This longitudinal eight-year clinical observation suggested that fired ceramic inlay restorations made by the G-Cera Cosmotech II system are clinically acceptable. However, critical failure as bulk fracture may become a future problem since marginal disintegration was detected in 77% of the restorations from microscopic and macroscopic perspectives.

Aluminum Silicates↗
PubMedDate not supplied

6-year clinical evaluation of fired ceramic inlays.

The purpose of the present study was to evaluate the quality of fired ceramic inlay restorations consisting of a feldspathic porcelain system (G-Cera Cosmotech II) after 6 years in vivo. A total of 49 fired ceramic inlays (for 27 premolars and 22 molars: class 1 in 11 teeth, class 2 in 36 teeth, and onlays in two teeth) were placed in 29 patients, and all restorations were evaluated at the time of placement, at 6 months, and 1, 2, 4, and 6 years after placement using modified USPHS criteria. Replicas made of the restorations were observed using a scanning electron microscope (SEM) to assess the state of the marginal area and wear of the restoration. Favorable color match was noted, and no bulk fracture, tooth fracture, or missing restorations were detected. Longevity was observed in 92% of the fired ceramic inlay restorations at 6 years (Kaplan-Meier method); however, marginal fracture was detected in six restorations (13%) and marginal discoloration in 11 (23%). SEM evaluation disclosed marginal microfracture in 49% of the restorations, wear in 19%, and wear of resin cement along margins in 36% at 6 years. No significant difference was observed in the incidence of each of these three characteristics between molars and premolars. This longitudinal 6-year clinical observation suggested that fired ceramic inlay restorations made by the G-Cera Cosmotech II system are aesthetic, durable, and clinically acceptable. Further follow-up is needed for the restorations showing marginal degradation and fracture from a microscopic and macroscopic perspective.

Dental Marginal Adaptation↗