| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Masahiro Hiroshima Univ, Faculty of Dent. Research Associate, 歯学部, 助手 (00294570)
TAMAMOTO Mitsuhiro Hiroshima Univ, University Dental Hospital, Lectuerer, 歯学部・附属病院, 講師 (00136110)
HAMADA Taizo Hiroshima University, Faculty of Dentistry, Professor, 歯学部, 教授 (50034244)
MAKIHIRA Seicho Hiroshima Univ, University Dental Hospital, Research Associate, 歯学部・附属病院, 助手 (80304450)
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| Budget Amount *help |
¥14,200,000 (Direct Cost: ¥14,200,000)
Fiscal Year 2000: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 1999: ¥9,700,000 (Direct Cost: ¥9,700,000)
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| Research Abstract |
The growth of a single isolate of C.albicans on saliva-, serum-coated or protein free (uncoated), thermocycled seven commercial resilient lining materials was investigated, by monitoring pH changes in growth media. The inhibitory effect of the tissue conditioners on fungal growth was observed using three parameters viz : i) delay in the onset of the rapid decline in pH, ii) reduction in the rate of pH change and iii) the pH minima reached. In the case of control soft liners (not thermocycled and uncoated), the antifungal effect appeared to depend upon the type of commercial soft liner used. Thus, an initial delay in pH decline, and very high pH minima were observed with fluoric and heat cured silicone materials. High pH minima were also observed with cold cured acrylic soft liners, whereas cold cured silicone materials, did not significantly differ from heat cured acrylic resin (p>0.05). However, the antifungal effect of the materials was significantly reduced both by thermal cycling (
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ANOVA ; p<0.01) and a layer of protein coating (saliva, p<0.05 ; serum, p<0.01). These results, taken together, suggest that the ageing of the materials and the biological fluids of the host, particularly serum, promote yeast growth on soft lining materials.
In the second study, the growth of a single isolate of C.albicans on saliva-, serum-coated or protein free (uncoated), thermocycled (4oC-70oC for 1min, respectively ; 0, 1000 and 10000 times) seven commercial soft lining materials were investigated, by adenosine triphosphate (ATP) analysis. In the case of control resilient liners (not thermocycled and uncoated), the fungal colonization appeared to depend upon the type of commercial resilient liner used. Thus, the lowest colonization was observed with fluoric and heat cured silicone materials, cold cure silicone materials, except for one product, and heat cured acrylic resin exhibited the highest colonization capacity, and cold cured acrylic resilient liners exhibited the intermediate. However, the fungal colonization on the materials was significantly promoted both by thermal cycling (ANOVA ; p<0.01) and a layer of protein coating (saliva, p<0.01 ; serum, p<0.01). These results, taken together, suggest that the aging of the materials and the biological fluids of the host promote yeast colonization on resilient lining materials. Less
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