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Biomedical subjects

S Ebisu

Publications and source records attributed to S Ebisu.

117 records · Page 7Linked to original sources
PubMedDate not supplied

Fluoride uptake in human teeth from fluoride-releasing restorative material in vivo and in vitro: two-dimensional mapping by EPMA-WDX.

Class V cavities were prepared in the upper and lower left second premolars from an individual under infiltration anesthesia. The cavities were filled with fluoride- releasing resin (TF). One month later, the teeth were extracted. As a control (in vitro), the upper and lower right second premolars were extracted at the time of the cavity preparation in vivo. Immediately after extraction, class V cavities were prepared and filled with TF, and immersed in normal saline solution for 1 month at 37 degrees C. All four premolars were bisected longitudinally and the fluoride uptake around the cavity wall on the cut surface was measured using an electron probe microanalyzer-wavelength dispersive X-ray method. The fluoride uptake was given in the form of a two-dimensional map. Comparison of the observed values of each corresponding part of the tooth in vivo and in vitro revealed no characteristic differences. The maps were quite analogous as a whole.

Adult↗
PubMedDate not supplied

Effect of cavity form and setting expansion of refractory dies on adaptability of fired ceramic inlays.

The purpose of this study was to investigate the effect of cavity form and setting expansion of refractory die materials on the adaptability of fired ceramic inlays. Standardized Class I cavities with three kinds of lateral wall divergences (10 degrees, 20 degrees, and 30 degrees) and three kinds of surface roughness were prepared in epoxy resin blocks. A refractory die was prepared from an impression of the epoxy resin cavity, whose setting expansion ranged from 0.01 to 1.13%. A ceramic inlay was fired on each die. The fabricated inlay was inserted into the epoxy resin cavity, and the interfacial distance between the ceramic inlay and the cavity wall at the margin was measured using a reflecting microscope at X100 magnification. The internal fit was measured after sectioning the specimen longitudinally. The results were analyzed by ANOVA and Sheffé's F test. Good adaptation was achieved with the smooth-surface cavity. The adaptability depended on the angle of the cavity divergence, and small gaps were observed in 20 degrees and 30 degrees cavities (P < 0.05). The inlays fabricated on the refractory dies with a small setting expansion demonstrated small internal gaps. Significantly good adaptation was achieved when the setting expansion was less than 0.2% (P < 0.05). The results indicated that the cavity form and the setting expansion of the refractory die material had significant effects on the adaptability of fired ceramic inlays.

Analysis of Variance↗
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

Effects of cavity form and setting expansion of refractory dies on adaptability of Class II (MO and MOD) fired ceramic inlays.

This study investigated the effects of cavity divergence and setting expansion of refractory die material on the adaptability of Class II (MO and MOD) fired ceramic inlays. Standardized Class II (MO and MOD) cavities with two kinds of lateral wall divergence (10 and 20 degrees) were prepared in epoxy resin blocks. A refractory die was prepared from an impression of the epoxy resin cavity in which the setting expansion ranged from 0.04 to 1.14%. A ceramic inlay was fired on each die. The fabricated inlay was inserted into the epoxy resin cavity, and the interfacial distance between the ceramic inlay and the cavity wall at the margin was measured using a reflecting microscope at x100 magnification. The internal fit was measured after sectioning the specimen longitudinally. The results indicate that the setting expansion of the refractory die materials and the divergence of the lateral walls had significant effects on the adaptability of Class II (MO and MOD) fired ceramic inlays. The inlays fabricated on the refractory dies with small setting expansion showed small internal gaps in Class II (MO) cavities. Significantly good adaptation was achieved when the setting expansion was 0.32% or less (p < 0.05). The inlays fabricated on the refractory dies with large setting expansion showed small internal gaps in Class II (MOD) cavities. Significantly good adaptation was achieved when the setting expansion was 0.87% and greater (p < 0.05).

Analysis of Variance↗
PubMedDate not supplied

Analysis of longitudinal marginal deterioration of ceramic inlays.

This study quantitatively and morphologically analyzed and clarified the longitudinal marginal changes of ceramic inlays and determined the mechanism for those changes. Epoxy replicas of 15 Class II ceramic inlays in permanent premolars prepared at baseline, 6, 12, 24, 48, 72 and 96 months after placement were selected. A CCD optical laser scanner was employed to measure quantitative changes in the occlusal surfaces of restored teeth. Longitudinal cross-sections of marginal areas of a ceramic inlay were computed, and two profiles of the same location obtained at different periods were superimposed using software. The area enclosed by the two profiles obtained at different periods was defined as the quantitative marginal change, and both the area and maximum depth in the area enclosed were calculated with picture analysis software. The marginal deterioration pattern was analyzed by drawing a longitudinal curve of quantitative change for each restoration. Morphological observation was carried out by scanning electron microscopy at magnifications from 20x to 75x. Quantitative measurement and morphological observation identified a sequential three-stage pattern of marginal deterioration; initial rapid progress of wear of resin composite cement in the first stage, followed by a second stage without any remarkable visible change, then rapid progression of microfractures of ceramics and/or enamel in the third stage. Boundaries between the first and second stage were found in the six and 21-month period, and those between the second and third stage at 72 months. It was concluded that longitudinal marginal deterioration of fired ceramic inlays progressed in a sequential three-stage pattern.

Dental Porcelain↗
PubMedDate not supplied

Comparative SEM and TEM observations of nanoleakage within the hybrid layer.

Most adhesive interface studies have involved SEM demonstration of the penetration of adhesive resins into demineralized dentin surfaces with subsequent creation of hybrid layers. Nanoleakage is a term that describes the diffusion of small ions or molecules within the hybrid layer in the absence of gap formation. The present microscopic study examined the nanoleakage of the hybrid layer using a silver nitrate staining technique. Adhesive dentin sandwiches, which were immersed in a silver nitrate solution, were prepared for both SEM and TEM examination using both the Clearfil Liner Bond and All-Bond 2 adhesive systems. Both systems demonstrated silver accumulation within the hybrid layers. Clearfil Liner Bond System showed scattered silver particles at the bottom two-thirds of the hybrid layer by both SEM and TEM observation, whereas All-Bond 2 revealed stained fiber-like structures within the full thickness of the hybrid layer. To evaluate the quality of the hybrid layer, the utilization of tracer molecules such as silver nitrate that are detectable by both SEM and TEM is proposed. It is important to determine the location and morphology of these nanometer-sized porosities that may permit the hydrolysis of collagen fibers and degradation of adhesive monomers.

Collagen↗
PubMedDate not supplied

Weight change of various light-cured restorative materials after water immersion.

This study investigated weight changes of various light-cured glass-ionomer cements and other restorative materials during water immersion and compared findings with those of conventional glass-ionomer cement and light-cured resin composites. Three light-cured glass-ionomer cements, two polyacid-modified composite resins, one conventional glass-ionomer cement, and one light-cured composite resin were evaluated in this study. The weight changes of these specimens after water immersion were measured using an electronic analytical balance and adjusted according to water solubility measured at the same time weight change was measured. The results were analyzed by one-way ANOVA and Scheffé's F test at P < 0.05. The weight change of Photac-Fil Aplicap was the largest, and there were significant differences among the materials (P < 0.05). Weight change after 6 weeks' water immersion was noted in the following order: Fuji Ionomer Type II LC, Vitremer, Fuji Ionomer Type II, VariGlass VLC, Geristore V, and Clearfil AP-X. It is suggested that the amount of water sorption of light-cured glass-ionomer cements is greater than that of polyacid-modified composite resins.

Absorption↗
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↗