| Project/Area Number |
02454437
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Okayama University |
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Principal Investigator |
INOUE Kiyoshi Okayama University Dental School Department of Operative Dentistry Professor, 歯学部, 教授 (60028727)
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| Co-Investigator(Kenkyū-buntansha) |
UTSUMI Seishi Okayama University Hospital attached to Dental School Depertment of Operative De, 歯学部附属病院, 講師 (10168726)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Keywords | Indirect composite resin inlay / Marginal fracture / Marginal leakage / コンポジットレジンインレ- / 窩縁形態 |
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| Research Abstract |
The purpose of the present study was to investigate the marginal fracture of composite inlay with each of three marginal forms-butt joint, straight bevel and round bevel, under simulated occlusal force and to estimate their clinical performance.
Six class 1 cavities with each marginal form were prepared on the surfaces of extracted incisors. Indirect composite inlay was inserted into the cavity with a dual-cured resin cement. Half of the restored teeth was subjected to 5000 thermocyclings between 4 and 60ﾟC and the other half was stored in water. After all teeth were subjected to the load cycling test designed for a stainless rod (weight : lkg) to fall repeatedly from the height of 1.5cm at 125 times/min, they were immersed in fuchsin solution for 24 hours. Degree of marginal fracture and leakage were observed. The teeth restored by direct composite filling technique were also tested as control. In clinic, carious molar teeth were restored with composite inlay with each marginal form. Clinical-estimation was performed at 0, 3 and 6 months later, using a USPHS criteria. The marginal integrity of the restorations was also observed by SEM.
Results were as follows ;
1. The frequency of marginal fracture of indirect composite inlay was lower than that of direct composite restorations. However it was increased by thermocycling, while in direct composite restoration there was no effect of thermocycling.
2. In indirect composite inlay without thermocycling, the order of the frequency of fracture was straight bevel>round bevel>butt joint.
3. The order of the degree of marginal leakage around both restorations after thermocycling was butt joint>round bevel>straight bevel.
4. Marginal leakage around indirect composite inlay was remarkably increased by thermocycling.
5. In clinical estimation, no marginal fracture around composite inlay was observed at the period of 6 months.
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