| Project/Area Number |
59870067
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
小児・社会系歯学
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Project Period (FY) |
1984 – 1985
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| Project Status |
Completed (Fiscal Year 1985)
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| Budget Amount *help |
¥11,400,000 (Direct Cost: ¥11,400,000)
Fiscal Year 1985: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1984: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Keywords | F-ISFET / pH-ISFET / transistor electrode / plaque F / plaque pH / cariogenicity |
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| Research Abstract |
The purpose of this study was to develop a method to evaluate the cariogenicity of plaque using a H,F multi micro transistor electrode.
1.Fablication and Characteristics of F Ion Sensitive Field-Effect Transistor(F-ISFET)
F-ISFET was produced by the simultanous method of pH-ISFET fablication.The ion sensing layer was made by thin layer of LaF that reacted to F ion reversibly.F-ISFET have shown a linear response and an ideal sensitivity in high concentration of NaF solution(above 10mol).But,in low concentration(below 10mol) of itF-ISFET's sensitivity and ion selectivity dropped.It was nessesary to improve the characteristics of F-ISFET.
2. Continuous measuring of oral F ion concentration following mouth rinsing with NaF solution.
F-ISFET placed in a casted metal-box and put on the maxilary first molar was used in oral cavity,and the residual F ion concentration following a mouth rinsing with 100ppm F standard solution was measured in situ. The obtained F ion concentration was above 10ppm immediately after mouth rinsing and after 15 to 20 minutes dropped below 1ppm.When the residual F ion concentration in oral cavity was high,the stable F concentration curve was obtained.This in-dwelling method should be applied for the measurement of F ionconcentration in plaque.
3.Difference of acidogenicity in plaque between children and adults.
Plage pH was continuously mesuared in situ.It was showed that the acid production of dental plaque after lactose or sucrose exposure was different among subjects and increased with age of plaque.In childrem,the returning time to pH 6 was shorter and the area between the pH curve and pH 6 level was smaller than that in adults.
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