2019 Fiscal Year Final Research Report
Elucidation of the mechanism of abfraction focusing on changes in cracks and minerals
| Project/Area Number |
16K20462
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Conservative dentistry
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| Research Institution | Tokyo Dental College |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Keywords | アブフラクション / クラック / マイクロCT |
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| Outline of Final Research Achievements |
There is complexity associated with the mechanical or chemical processes in the creation of abfraction lesions. This study aimed to analyze mineral density and micro-cracks in extracted teeth with NCCL after demineralization, using micro-CT. Premolars with NCCL were immersed in a demineralization solution. After demineralization, the specimens were scanned by micro-CT. Thin sections were then prepared for SEM examination. The changes in width of cracks in the enamel surface were measured at each time point. Micro-CT images around the CEJ showed destruction of the enamel layer after demineralization. The length and width of cracks were increased significantly after demineralization. Comparisons of the micro-CT and SEM images revealed that the lines of the cracks were at the same positions. Micro-cracks on the cervical surface of human premolars with NCCL were detected by micro-CT. Demineralization of the cervical region progressed along the micro-cracks.
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| Free Research Field |
保存修復学
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| Academic Significance and Societal Importance of the Research Achievements |
エナメル質が菲薄化した歯に過度な咬合力が加わることにより，エナメル質から象牙質へ達するマイクロクラックが生じる可能性があり，臨床症状として歯の審美障害，歯の破折，歯髄疾患などを引き起こす誘因となる．非う蝕性の歯頸部欠損は咬合が関与すると考えられ，アブフラクションと呼ばれる．マイクロクラックの3次元的観察の結果から，脱灰によるエナメル質のマイクロクラック長さと幅の増加を認めた．このことは，脱灰が歯頸部に存在したクラックに沿って進み，CEJ付近のエナメル質の菲薄化と，咬合による歯頸部の応力集中などによって歯頸部欠損がさらに進行する可能性が考えられた．
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