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Volume 10 (1991)
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 10, Issue 1
Displaying 1-9 of 9 articles from this issue
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Yoshihiro MURAKAMI, Norikatsu TSUKADA, Moriyasu WADA, Muneyoshi YAMAZA ...1991 Volume 10 Issue 1 Pages 1-7,97
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSIn this study we investigate the adhesiveness of composite resin on pulpal side dentin treated with the primer MTYA·G·H as compared with that for labial side dentin. Fresh bovine dentin was used; the labial and pulpal surfaces were prepared as adherends. The etching agents were 40% phosphoric acid, 10% citric acid, or 0.5M EDTA (pH 7.4) solutions. Tensile bond strengths were measured after immersion for one day in 37°C water. There was no significant difference between the mean bond strength for labial side dentin and that for pulpal side dentin for each etchant. The highest mean bond strength, about 12MPa, was obtained when pulpal side dentin was etched with EDTA. It is concluded that MTYA·G·H treatment of the deep portions of the dentin is effective in obtaining good adhesion.View full abstractDownload PDF (2146K) -
Ikuro HARASHIMA, Takashi NOMATA, Tadashi HIRASAWA1991 Volume 10 Issue 1 Pages 8-17,97
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe degree of conversion (DC) of dual-cured composite luting materials for composite inlay restoration was determined by Fourier transform infrared spectroscopy. Dual-cured composite cements showed a DC of 59.3-75.0% after self-cure and 66.6-81.4% after photo-cure. DC after photo-cure decreased with the increase in thickness of a restoring composite inlay between the composite cement and a light tip. A lower DC after photo-cure did not satisfactorily increase following subsequent self-cure. Sufficient light should be provided to the composite cement in photo-cure luting of composite inlays to achieve a high and uniform DC, as well as in filling restoration using photo-cured composites. Reirradiation, in which the tip of a light unit was brought close to the portion of the cement with a low DC, was very effective in increasing DC and making it more uniform.View full abstractDownload PDF (1371K) -
Seiichiro FUJISAWA, Yoshinori KADOMA, Yasuo KOMODA1991 Volume 10 Issue 1 Pages 18-26,97
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSTo clarify the mechanism of interaction of dental adhesive monomers with biological membranes at the molecular level, we studied the interaction of 4-META and its related compounds (4-methacryloyloxyethoxy-carbonylphthalic acid 4-MET, phthalic acid and phthalic anhydride) with the dipalmitoylphosphatidylcholine (DPPC) liposome system, using NMR and DSC. Changes in NMR chemical-shifts and phase transition temperatures at pH 7.4 of DPPC liposomes induced by phthalic anhydride and 4-META were greater than those induced by phthalic acid. NMR spectra of the DPPC/4-META liposome system were similar to those of the DPPC/4-MET liposome system, suggesting hydrolysis of the anhydride moiety of 4-META in D2O. The effects of 4-META and its related compounds on human erythrocytes were also studied. 4-META and phthalic anhydride showed a greater degree of hemolysis as compared to 4-MET and phthalic acid, indicating that ionized compounds do not impregnate into biological membranes.View full abstractDownload PDF (1766K) -
Hisao FUKUI, Jiro HASEGAWA, Kuniji ICHIDA, Teiichi OHKOUCHI1991 Volume 10 Issue 1 Pages 27-37,98
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSAlthough the mechanical properties of dental alloys have been studied by static tests including tensile tests and hardness tests, the measurements of endurance strength in which the fatigue properties of the dental alloys are considered have not yet been performed. It has been reported that fatigue fracture occurs in these alloys even when recurring stresses are lower than their yield strength. The purpose of this study is to measure several different fatigue properties in five varieties of wrought gold alloys. The relationships between stress amplitude (σa) and number of stress cycles (N) were studied using a four point bending testing machine at a frequency of 30Hz. After the fatigue tests, the fracture surfaces were observed by SEM.
The alloys with small elongation and comparatively high tensile or yield strength showed high fatigue strength. Gold alloys having such high fatigue strength cracked through a striation process named stage II from their crack inception.
We conclude that it is indispensable to consider the mechanical properties of dental alloys as measured by dynamic tests as well as by static ones.View full abstractDownload PDF (4627K) -
Miki IGA, Fumio TAKESHIGE, Takashi UI, Mitsuo TORII, Yasuhiko TSUCHITA ...1991 Volume 10 Issue 1 Pages 38-45,98
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSDownload PDF (1742K) -
Part I: Disintegration Properties and Biological ResponsesHiroshi KIMURA, Hwal SUH, Masayuki OKAZAKI1991 Volume 10 Issue 1 Pages 46-57,99
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSAn artificial bone defect filling material with appropriate plasticity was prepared from non-sintered CO3 apatite (Ap) and enzymatically-treated atelocollagen fibers, and is reffered to as the apatite-collagen composite. To improve the binding activity of the collagen fibers, the composite was irradiated with ultraviolet radiation for 4 hours. In vitro, the composite was placed in a 0.9% NaCl solution to observe disintegration rates, weight loss rates, and Ca2+ ion derivation rates. The UV-ray irradiated Ap-10wt% collagen composite showed the least disintegration, the non-irradiated Ap-5wt% collagen composite showed the greatest disintegration. To observe biological aspects, the composite was embedded into the mandibular borders of Sprague-Dawley rats for 1, 2, 4, 8 and 12 weeks, and histological changes observed by light microscopy of the cortical bone area. The collagen fibers in the composite disappeared within 2 weeks after implantation. The apatite was adhered well to the bone without significant abnormal histological changes during the period of experimention.View full abstractDownload PDF (3876K) -
Tohru WATANABE, Miyako YOKOYAMA, Kazuo ITOH, Sadao WAKUMOTO, Tetsuhiko ...1991 Volume 10 Issue 1 Pages 58-64,99
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSThe pulp reactions to a dentin bonding system including dentin priming with an aqueous solution of 35% glyceryl methacrylate (GM) were examined by observing the pathological change in the pulp of dog teeth restored by the combination of enamel etching with phosphoric acid gel, dentin cleaning with neutralized EDTA solution, dentin priming with the GM solution, and a chemically activated composite mediated by a commercial dentin bonding agent. It is concluded that it is possible to effectively use GM, because no serious irritation was observed in the tested specimens, although slight regressive change was seen in the early stages after restoration.View full abstractDownload PDF (4195K) -
Nobuyuki TANAKA, Hideaki SHINTANI, Masayuki TAIRA, Kunio WAKASA, Masao ...1991 Volume 10 Issue 1 Pages 65-71,99
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSAs a step in evaluating the feasibility of the use of machinable ceramics in dentistry, two machinable ceramics, a mica-containing glass ceramic and a boron nitride-containing aluminum nitride ceramic, along with a control apatite-containing glass ceramic, were examined for surface polishability Using a profiliometer and for machinability employing SEM. Although polishing of the two machinable ceramics with sand paper resulted in rougher surfaces, dental high-speed cutting of the two machinable ceramics produced smooth surfaces with little chipping, as compared with those of the control glass ceramic. It is speculated that the cleavage of dispersed crystals in the matrix phases gave the two machinable ceramics excellent machinability but limited surface polishability. For intra-oral applications of machinable ceramics, we expect that polishability can be improved by modification of their microstructures.View full abstractDownload PDF (3387K) -
Kazuyuki KATSUNO, Atsufumi MANABE, Sadao NAKAYAMA, Tetsuhiko TACHIKAWA ...1991 Volume 10 Issue 1 Pages 72-78,100
Published: June 25, 1991
Released on J-STAGE: February 12, 2009
JOURNAL FREE ACCESSMorphological changes produced by the application of dentin primer were examined by observing histological responses to the repeated application of aqueous solutions of 35% hydroxyethyl methacrylate and 35% glyceryl methacrylate. One of these two experimental primers was applied to the shaved skin of male Sprague-Dawley rats every eight hours for 21 days. After confirming the disappearance of the inflammation 36 days after the start of the test, the primer application was repeated for an additional 19 days for a total of 55 days. After completion of the primer application, slight hyperkeratosis, which was diagnosed as contact dermatitis, was observed in the epidermis of the treated skin in both the HEMA and the GM groups. These pathological changes were observed as scattered slight hyperkeratosis and slight hypertrophy of the sebaceous glands after both the 21 day and 55 day applications.View full abstractDownload PDF (3123K)
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