| Project/Area Number |
16K15794
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Multi-year Fund |
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| Research Field |
Conservative dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
Ikeda Hideharu 東京医科歯科大学, 歯学部, 非常勤講師 (20222896)
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | エナメル質 / 電気伝導率 / 飛行時間型質量分析計 / 透過性 / 象牙質 / ＴＯＦ－ＭＳ / 電気伝導度 / 歯髄 / 定量測定 / 物質透過性 / TOF-MS / 定量測定法 / DDS |
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| Outline of Final Research Achievements |
Two methods, Time-of-flight mass spectrometer (TOF－MS) and electric conductometry, were used. The spectrometry was used to determine an ion's mass-to-charge ratio via a time of flight measurement. Electric conductometry was used to quantitatively evaluate chemical permeability through enamel/ dentin. Freshly extracted healthy molars were used to measure chemicals which passed from enamel side to pulp side for both experiments. Using TOF－MS, capsaicin and urea hydrogen peroxide could be detected. Electrical conductance correlated closely to a quadratic function of the concentration of capsaicin (r2 = 0.985) or urea hydrogen peroxide (r2 = 0897).
The results obtained from the present study have clarified that combined usage of the two methods enables to quantitatively measure the chemical passed though enamel, and therefore to show the effect of acid-etching, enamel bleaching and even acid food/drink on chemical pulp injury.
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| Academic Significance and Societal Importance of the Research Achievements |
エナメル質／象牙質を通過し歯髄に進入する低分子物質の定量分析を行うことは困難であった。本研究で我々はTOF－MSと電気伝導率の二つの方法を用いて、通貨物質を定量的に測定できることを明らかにした。つまり、口腔内に入る刺激物質にエナメル質が曝された時に、歯髄内に進入する物質量の定量計測ができた。
この方法を応用することにより、歯科治療でエナメル質性状を化学的に変化させる漂白処置・酸処理や、酸蝕を引き起こすことが近年注目されている酸性食品が原因で生じるエナメル質と象牙質の構造変化に起因する組織傷害性物質の歯髄内侵入量の変化を定量計測し、データを基に口腔の健康を目標とした啓蒙ができると考えられる。
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