Biomedical subjects
Publications and source records attributed to S Inokoshi.
The objective of this paper is to review the literature concerning factors affecting adhesion to mineralized tissues. Factors related to the physicochemical structure of the adherents and to the inherent properties of composite restorative materials, along with the postulated bonding mechanisms of current adhesive systems, are discussed.
Pulpal response to marginal enamel etching or both enamel and dentine etching with 37% phosphoric acid for adhesive composite restorations was studied in the teeth of the Japanese monkey (Macaca fuscata). Dentine etching irritated the pulp and caused moderate to severe initial changes along the odontoblastic layer at 3 days. When no bacteria were present along the cavity walls, the subsequent pulpal reactions at 30 and 90 days decreased with time and large amounts of irritation dentine were formed. These inflammatory reactions were less than those caused by enamel etching only, or zinc oxide/eugenol cement. Significant correlation (P less than 0.01) was found between the intensity of the inflammatory reactions and the degree of bacterial infection. The pulpal irritation caused by acid etching of dentine for composite restorations is transitory only when the fillings have a good marginal seal and wall adaptation.
A 99.5 per cent pure aluminium step-wedge served as reference for evaluating the radiopacity of 55 anterior and posterior composites. The radiopacity of all materials evaluated was compared with the radiopacity of human enamel and human dentine of equivalent sample thickness. Seventeen composites exhibited a radiopacity significantly greater than that of enamel. Some composites intended for posterior use lack the radiopacity required for posterior composite restorations.
Twenty-four chemically cured, 21 light-cured anterior, three light-cured anterior/posterior, and 18 light-cured posterior composite resins were examined using scanning electron microscopy, and the elemental composition of their filler particles was analyzed with an energy dispersive electron probe microanalyzer. According to the results obtained, the composite resins were divided into five groups (traditional, microfilled type, submicrofilled type, hybrid type, and semihybrid), with two additional hypothetical categories (microfilled and hybrid). Characteristics of each type were described with clinical indications for selective guidance of respective composite resins for clinical use.
A newly developed light-cured anterior restorative composite resin "Graft LC" by GC Co. is characterized by having Vita VMK 68 shades and containing glass filler particles treated with graft binders. Several properties of the resin were examined by using the SEM, surface recorder, and color analyzer. The Graft LC resin was classified as semi-hybrid resin. The filler particles of Graft LC resin comprised two kinds of glass filler in which Si, Ba and Al, and Si were detected. Graft LC resin showed a relatively small surface roughness after polishing in spite of the semi-hybrid resin. According to the degradation test in the alkaline solution, the polished surfaces of Graft LC resin became rough and the depth of subsurface damage layer increased with time. However, the filler particles were retained in the subsurface damage layers. An Ar ion etching employed for SEM preparation is useful to observe the subsurface damage layer distinctly under the SEM. No color change was found even after long-term immersion in a distilled water, though the color of Graft LC resin changed greatly due to irradiation.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The pulpal response to a new adhesive restorative resin was histopathologically investigated using dogs, and was compared with a representative conventional resin. When filled without etching and cavity wall lining, bacterial penetration and pulpal response were less with the new resin. Lining of dentin walls and total etching of cavity walls, including dentin, caused less pulpal response under the new resin. Cavities which were totally etched and filled with the new resin showed only a slight pulpal response and no bacterial penetration.
Explore the source record for details and available documents.
OBJECTIVES: To compare the in vitro shear bond strength of two commercially available resin-modified glass ionomer cements (RmGIC) to bovine dentine, with and without the use of adhesive bonding systems. METHODS: Ninety-six flat bovine dentine surfaces were divided into eight groups for bonding procedures. Fuji II LC and Vitremer were bonded to dentine that had been treated with and without Clearfil Photo Bond, Clearfil Liner Bond, or Clearfil Liner Bond II. The control group consisted of specimens that were treated as recommended by the manufacturer of each resin-modified glass ionomer cement. The bonded assemblies were stored in tap water for 24 h at 37 degrees C, and shear bond strengths measured using a universal-testing machine at a crosshead speed of 1 mm/min. RESULTS: For the control group, shear bond strength of Fuji II LC was significantly greater than Vitremer (P < 0.005). However, when any of the resin bonding systems was applied, no statistical difference between Fuji II LC and Vitremer was determined (P > 0.05). The Clearfil PhotoBond and Liner Bond groups showed similar bond strengths (P > 0.05), but were significantly less than Liner Bond II (P < 0.001). CONCLUSIONS: A recent bonding system combined with the RmGICs exhibited the greatest shear bond strength to dentine, irrespective of chemical differences that may exist between the two RmGICs.
Objectives of the study were to compare the capacity of fluoride releasing materials to inhibit in vitro caries formation and to measure the width and height of the inhibition zones. Box-shaped cavities were prepared on bovine root dentine and restored with Fuji II, Fuji II LC. Vitremer, or Clearfil Liner Bond II system with a fluoride releasing composite. After immersion in a buffered demineralizing solution of 50 mmol/L acetic acid adjusted to pH 4.5 for 3 days, longitudinal sections were cut and imbibed in quinoline for analysis under a polarized light microscope (PLM). The contours of the lesions and inhibition zones were traced and their depth, width and height calculated. The data were analyzed by one-way ANOVA and Fisher's PLSD test at 95% level of confidence. The polarized light microscopy results showed a distinct inhibition zone adjacent to both conventional and resin-modified glass ionomer cements; however, it was not observed around the adhesive resin system. The width and height of this inhibition zone were significantly greater for Fuji II than for Fuji II LC and Vitremer. An inhibition zone was not observed adjacent to the adhesive resin system with fluoride releasing composite. The resin-modified glass ionomer cements produced less protection against in vitro secondary caries formation than the conventional glass ionomer cement. The recent bonding system that releases fluoride failed to produce an inhibition zone along the cavity wall adjacent to the restoration.
This in vitro study evaluated the interfacial integrity of Class II resin composite restorations. The influence of a flowable composite and additional enamel etching was also evaluated. Deep, saucer-shaped Class II cavities were prepared in the mesial and distal proximal surfaces of 25 extracted human molars and assigned to five treatment groups. The gingival margins were extended to approximately 1 mm above the CEJ in 40 cavities and below the CEJ in 10 cavities. The prepared cavities were then restored with a self-etching primer system (Clearfil Liner Bond II) and a hybrid resin composite (Clearfil AP-X), with and without a flowable composite (Protect Liner F) and additional enamel etching with 37% phosphoric acid gel (K-etchant). After finishing, polishing and thermocycling (4 and 60 degrees C, x300), the samples were longitudinally sectioned through the restorations and resin-tooth interfaces were observed directly under a laser scanning microscope. Statistical analysis indicated that the use of a flowable composite produced significantly more (p = 0.04) gap-free resin-dentin interfaces than teeth restored without the flowable composite. However, both flowable composite and enamel etching could not prevent gap formation at enamel-resin interfaces and crack formation on enamel walls.
The interfacial structure between an adhesive composite resin and dentin after caries removal and acid conditioning was investigated. The hybrid layer between the adhesive resin and surface-demineralized dentin was found to be wider in the area of empty tubules compared with that of the occluded tubules, and was found to be the thinnest at the lateral walls of the cavity where the dentinal tubules run parallel to the cavity surface. Thus, the extent of demineralization by acid conditioning as well as impregnation of resin into the intertubular dentin forming the hybrid layer is probably related to the degree of closure and direction of the dentinal tubules.
This study evaluated the pulp biocompatability of a new light-cured composite resin which was placed in etched glass-ionomer-lined cavities of monkey teeth. The pulpal response to this material was less than that to zinc-oxide eugenol cement in each observation period. Therefore this material seems to meet acceptable biocompatability standards in nonhuman primates.
Explore the source record for details and available documents.
Monkey pulpal responses to resin-bonded indirect resin composite inlays were histopathologically evaluated by placing them in either etched-enamel, total-etched, or adhesive-resin-lined cavities. Initial pulpal responses caused by re-exposure of the cut dentin surfaces and luting procedure subsided if a tight marginal seal was secured by final cementation of the inlay. The adhesive resin coating of freshly cut dentinal walls/floors seems to provide a new technique to protect the dentin and pulp in indirect restorations requiring temporary sealing.
The interfacial structure between an adhesive composite resin and the dentinal walls of cervical erosion/abrasion lesions etched with 37% phosphoric acid gel for 60 seconds was investigated. Almost all dentinal tubules were occluded with rod-like structural depositions that remained undissolved even after acid conditioning. The hybrid layer between the adhesive resin and surface-demineralized dentin was found to be 0.3 to 3 microns, much thinner than that routinely found in either normal dentin or cariously affected dentin. The hybrid layer was thinnest at the occlusal walls of the cavity where the dentinal tubules run parallel to the cavity surface. The bond strength of adhesive resin to these areas may differ from that to intact normal dentin.