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Biomedical subjects

H Onose

Publications and source records attributed to H Onose.

At least 37 records · Page 2Linked to original sources
PubMed1995

Influence of light irradiation of dentine primers on dentine-resin bond.

OBJECTIVE: The purpose of this study was to examine the influence of light irradiation of dentine primers that contain camphoroquinone (CQ) on the shear bond strength to dentine and their contact angle. METHOD: Three dentine bonding systems which contain CQ, Imperva Bond, OptiBond and XR-Bond; and Light Bond, which does not contain CQ, were employed. Labial surfaces of freshly extracted lower bovine incisors were ground with no. 600 grit SiC paper. Dentine primers were applied to the dentine surfaces in two groups, irradiated and non-irradiated. A shear bond strength test was performed and the direct contact angle was measured. RESULTS: Statistical analysis (Newman-Keuls multiple comparison P < 0.05) of the data indicated that light irradiation of the dentine primer for systems containing CQ resulted in increased bond strength and decreased contact angle. CONCLUSION: This study indicates that for these dentine bonding systems containing CQ in their primers, light irradiation of the dentine primer is effective in improving wettability and increasing the bond strength to dentine.

Analysis of Variance↗
PubMed1995

Suicide and aging in Japan: an examination of treated elderly suicide attempters.

Although individuals aged 65 and over accounted for 12% of the total population of Japan in 1990, suicides in this age group consisted of 29% of all suicides. The elderly population of Japan is expected to grow rapidly to 24% of the total population by the year 2020, and suicide prevention for the elderly is an urgent mental health problem. Among a total of 1,216 elderly patients who were admitted to the Department of Psychiatry at Tokyo Metropolitan Geriatric Hospital between April 1980 and March 1990, 50 were hospitalized immediately after suicide attempts in order to study their psychosociomedical problems. Because early diagnosis of depression and initiation of proper treatment are indispensable--even if patients do not show obvious depressive symptoms--those who develop persistent somatization and/or delirium should be considered highly suicidal and given special attention. With the cooperation of mental health professionals, it is necessary to educate general practitioners, the public, and the elderly themselves about characteristics of psychiatric disorders and various problems associated with aging. Further research on other elderly Japanese populations, as well as research that examines suicide completion, is needed to confirm the findings of the present study.

Age Distribution↗
PubMed1995

Influence of light intensity on shear bond strength to dentin.

PURPOSE: To investigate the influence of light intensity on dentin bond strength of five dentin bonding systems. MATERIAL AND METHODS: The light intensity used to polymerize specimens was controlled at the levels of 100, 200, 400, 600, 800, and 1000 W/m2 (470 +/- 40 nm). Labial surfaces of freshly extracted lower bovine incisors were ground with #600 grit SiC paper to expose dentin. After primer application, bonding agents were applied and bonded with resin composites. A shear bond strength test was performed and the data were analyzed by a one-way ANOVA followed by Newman-Keuls multiple comparison (P<0.05). RESULTS: Statistical analysis of the data indicated that light intensity affected the bond strength to dentin. The mean bond strength of all bonding systems decreased with lower light intensity. The tendency of decreasing bond strength was different among the test materials and each test material had a threshold light intensity that resulted in statistically the same bond strength obtained using a light intensity of 1000 W/m2.

Analysis of Variance↗
PubMed1994

Effect of D-Ala-D-beta Nal-Ala-Trp-D-Phe-Lys-NH2 (KP-102) on GH secretion in urethan-anesthetized rats.

The effect of a newly developed growth hormone (GH)-releasing hexapeptide (KP-102) on GH secretion was studied in urethan-anesthetized adult male rats. Although KP-102 alone exerted a small influence on GH secretion, it produced a large plasma GH response in the presence of exogenous GH-releasing factor (GRF). During the continuous infusion of GRF, the somatotropes became refractory to a large bolus dose of GRF, but KP-102 induced a marked increase of plasma GH. The GH response to KP-102 alone or KP-102 with GRF was significantly augmented when antiserum to somatostatin (ASS) was previously administered. Although KP-102 and GRF acted synergistically on GH secretion in control animals, they acted additively in ASS-administered rats. The KP-102 effect on plasma GH was significantly attenuated in control animals and ASS-administered rats by prior i.v. injection of antiserum to GRF. Taken together, KP-102 stimulates GH secretion dependent on GRF and appears to act synergistically with GRF by antagonizing the SS effect.

Animals↗
PubMed1993

Influence of argon laser curing on resin bond strength.

Light cured resin composites are usually cured with halogen lamps whose light output decreases with time and distance to the resin surface. This study compared bond strengths of resins to tooth structure cured with either an argon laser or a conventional halogen light. The enamel and dentin of bovine incisors were ground on the buccal surface with wet #600 grit SiC paper. A 4 x 2 mm mold was placed on the tooth surface and Scotchbond 2/Silux and Clearfil Photobond/Photo Clearfil A were placed into the molds and cured using a Quick Light or an argon laser for exposure times of 10, 20, and 30 seconds, and distances of 0.0, 0.5, 1.0, and 1.5 mm from the resin surface. The intensity of the Quick Light was measured as 510 mW/cm2 at 470 +/- 15 nm and the intensity of the argon laser was adjusted to 510 mW/cm2 before curing. Shear bond tests at a crosshead speed of 1.0 mm/min were performed after 24 hours of storage in water. The bond strengths obtained with the halogen lamp and the laser were not significantly different at the same exposure times and at 0.0 or 0.5 mm from the resin surface. The laser cured bond strengths did not decrease with increasing distance whereas there was a significant decrease in halogen bond strengths at distances greater than 0.5 mm for both resins. The use of the laser might provide a clinical advantage in cases where the curing light source cannot be brought into proximity to the surface of the resin.

Animals↗
PubMed1991

Effect of filler content of light-cured composites on bond strength to bovine dentine.

The bonding of light-cured composites to tooth tissues is known to be disturbed by polymerization shrinkage, and polymerization shrinkage is affected by the filler content of composites. This in vitro research examined the relationship between the filler content and bond strength to dentine of light-cured composites. Experimental light-cured composite systems with filler contents of 45, 55, 65 and 75 per cent by volume were used in both bond strength to dentine and shrinkage tests. The surfaces selected as substrates were a flat surface and a box-shaped cavity prepared in bovine dentine. The lowest bond strength was obtained with the 45 per cent filler content composite in the box-shaped cavity. Bond strength increased with increasing filler content. Volumetric polymerization shrinkage decreased with increasing filler content. The polymerization shrinkage at 120 s after light curing was 5.24 per cent for the 45 per cent filler content system, 4.77 per cent for the 55 per cent, 2.14 per cent for the 65 per cent and 1.68 per cent for the 75 per cent. The correlation between bond strength and shrinkage was greater for the cavity than it was for the flat surface. This implies that bond strength in the box-shaped cavity may have been affected more by polymerization shrinkage than with the flat surface. The findings lend support to the view that filler content is one of the important factors influencing the physical properties of composites.

Acid Etching, Dental↗
PubMed1991

Dentin bond strength of light-cured glass-ionomer cements.

The purpose of this study was to investigate the influence of surface treatments and irradiation conditions on the bond strength of light-cured glass-ionomer cements to dentin. The light-cured glass-ionomer cements used in this study were Vitrabond, XR Ionomer, and Fuji Lining LC. Three experiments were designed to study the influence of the following factors on bond strength to dentin: (1) effect of the surface treatment of the dentin, (2) effect of the irradiation time, (3) effect of an increase in the interval between mixing of the cement and irradiation. Samples were stored in water for 24 hours, after which shear bond testing was performed at a cross-head speed of 1 mm/min. For Vitrabond, the Scotchprep and Gluma 2 treatments gave the greatest shear bond strengths. For XR Ionomer and Fuji Lining LC, the Scotchprep treatment gave the greatest shear bond strengths. The bond strengths for all cements increased with prolonged irradiation time. Bond strengths decreased with a longer elapsed time between mixing and light-curing. This means that light-curing should be done soon after the cement is placed. The failure mode was found to be cohesive in the ionomer.

Acid Etching, Dental↗
PubMed1991

Effect of irradiation time to light-cured resin composite on dentin bond strength.

This study examined the relationship between the irradiation time of three light-cured resin composites and their bond strength to dentin using two adherend surfaces. The light-cured resin composite systems selected were: Scotchbond/Silux, Scotchbond 2/Silux, and Clearfil Photo Bond/Photo Clearfil A. The adherend surfaces selected were a flat dentin surface and a box-shaped cavity. The greatest bond strength for all resin systems was recorded using the longest irradiation time. The bond strengths increased with an elevated irradiation time. When comparing the flat surface and a box-shaped cavity, the bond strength of the box cavity was greater than the flat surface with similar conditions except for 20 and 30 seconds of Scotchbond and 30 seconds of Clearfil. The correlation between bond strength and irradiation was greater for the flat surface than for the box-shaped cavity. This implied that the bond strength of the box-shaped cavity may be more susceptible to polymerization shrinkage.

Animals↗
PubMed1990

Factors of glass-ionomer cements influencing the bond strength to resin composites.

The bond strength between composites and various particle sizes of glass-ionomer cements was investigated. The best bond strength was obtained after use of a small-particle cement and with the highest powder-to-liquid ratio employed for mixing the cement. In addition, use of a small-particle cement and the highest powder:liquid ratio produced cements with significantly stronger tensile strengths. Failure usually occurred within the cement. Consequently, the recorded bond strength actually reflected the tensile strength of the relevant cement.

Composite Resins↗