The purpose of this study was to determine the elastic modulus of components at the resin-dentin interface with the use of an ultrasound device. Dentin slabs were obtained from freshly extracted bovine incisors shaped into a rectangular form. After demineralization, the dentin specimens were immersed in adhesives and polymerized. Adhesives were also polymerized and trimmed into the same shape as the dentin slabs. The specimens were then immersed in distilled water at 37°C for up to one year. The ultrasound equipment employed in this study was a Pulser-Receiver, transducers and an oscilloscope. By measuring the longitudinal and shear wave sound velocities, the elastic modulus was determined. When the elastic modulus of adhesive resin-infiltrated demineralized dentin was compared with that of adhesives, slightly but significantly lower values were found for adhesives used in a self-etching primer system. On the other hand, a higher elastic modulus was observed for resin-infiltrated dentin than for an adhesive used in an etch and rinse system. The elastic modulus of the resin-infiltrated dentin prepared with the etch and rinse system was affected by long-term storage in distilled water. (J. Oral Sci. 50, [481][482][483][484][485][486] 2008)
The purpose of this study was to investigate the effect of previous phosphoric acid etching on the dentin bond strength of single-step self-etch adhesive systems. Facial surfaces of bovine teeth were wet ground with #600 SiC paper. Adhesives were applied with and without previous phosphoric acid etching, and light irradiated. Resin composite was bonded to the adherend surface, followed by light irradiation and storage in water at 37 degrees C. Four groups (n = 10) were made per adhesive system: with and without previous acid etching and with and without thermal cycling between 5 degrees C and 55 degrees C for 10,000 cycles. Specimens were tested in a shear mode at a crosshead speed of 1.0 mm/min. Two-way ANOVA and Tukey HSD test at a level of 0.05 were performed. The changes in dentin bond strengths were different among the adhesive systems tested. In all experimental conditions of this study, the dentin bond strength decreased or remained unchanged with previous acid etching. From the results of this study, previous acid etching might not be acceptable for increasing dentin bond strength of the single-step self-etch adhesive systems.
Between 1997 and 1999, the prevalence of Demodex canis mites was determined in 150 dogs. In two dogs, we found two different species of mites; Demodex canis and another, unidentified, Demodex mite. The unidentified Demodex mite species had several different morphological features. First, it had a short opisthosoma and an obtuse end. In addition, the fourth coxisternal plate was rectangular and there was a band-like segmental plate between the fourth coxisternal plate and opisthosoma. Although all of the morphology and the development of male mites could not be investigated in this study, the location of the opisthosoma and the genital pore clearly differed from Demodex canis, suggesting that this unidentified mite is a new species.
ABSTRACT. A serological survey with latex agglutination test to detect anti-Toxoplasma gondii antibodies was conducted on 800 serum samples collected from domiciled cats at animal hospitals in various areas of Japan. The overall prevalence was 6.0% (48/800). Among 48 positive individuals, there was no specific distribution of strength of antibody titers; the titers were 1:64 in 8 cats, 1:128 in 12, 1:256 in 8, 1:512 in 10, 1:1,024 in 8 and 1:2,048 in 2. The maximum prevalence was 15.4% in 13 cats at 17-23 yrs old group, whereas all were negative in 58 cats aged 12-16 yrs. The age groups in the order of higher prevalence were 8, 4, 10, 5, 3, and 7 yrs, showing no aging effect to the prevalence. In terms of rearing conditions of those cats, they were classified into 4 groups, i. e., indoor, free, outdoor, and others. The prevalence in the outdoor group (11.1%) was significantly higher (p<0.05) than that in the free group (4.8%). Epidemiological aspects observed in the domiciled cats were different from those reported in the stray cats. -KEY WORDs: epidemiology, feline, prevalence, Toxoplasma gondii.
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