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Study on Toughening of composite resins using fatigue crack propagation test

Research Project

Project/Area Number 07457455
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Conservative dentistry
Research InstitutionOsaka University

Principal Investigator

TAKESHIGE Fumio  Osaka Univ., Hospital Attached to Fac.of Dentistry, Assistant Professor, 歯学部・附属病院, 講師 (60206969)

Co-Investigator(Kenkyū-buntansha) HAYASHI Mikako  Osaka Univ., Hospital Attached to Fac.of Dentistry, Instructor, 歯学部・附属病院, 助手 (40271027)
KAWAI Keiji  Osaka Univ., Hospital Attached to Fac.of Dentistry, Assistant Professor, 歯学部・附属病院, 講師 (40204664)
Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
Budget Amount *help
¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
KeywordsComposite resin / Fatigue strength / Fatigue crack / Filler / Toughening / 高靱化
Research Abstract

The equation, da/dN=C (DELTAK) ^m, could be applied to the fatigue crack propagation of the composites both in the atmosphere and in the water environment. The DELTAK_<th> for composite resins in the atmosphere was in the range of 0.43-0.82MPa・m^<1/2>, and that in the water increased to the range of 0.52-1.12Mpa・m^<1/2.> The expansion of matrix due to the water absorption enhanced the fatigue resistance of composites. The residual compression stress in the matrix might arrest the fatigue crack.
The fatigue crack of dental composites propagated mostly along the interface between inorganic filler and matrix. In the contrast to inorganic filler, some organic fillers were penetrated with fatigue cracks. The crack was bridged, bowed or deflected by the inoganic filler, and consequently the energy release rate for crack propagation was increased. These showed that crack deflection and crack bridging by inorganic filler increased the fatigue resistance of composites. The inorganic filler larger than 10mum was effective in arresting the fatigue crack propagation. The aspect ratio and the size of inorganic filler in composites might be influential factors for their fatigue resistance.
There was no significant reduction of bending strength after 3m aging in water. On the contrary, the fatigue resistance measured as DELTAK_<th> was decreased by aging for only 1m. Fatigue crack growth rate was more sensitive to degradation of composites by aging in water than bending strength.
Thus, it can be concluded that the crack deflection and the crack bridging by inorganic filler increase the fatigue resistance of composites, and the expansions of matrix due to the water absorption enhance the fatigue resistance of composites. From the present study, it was shown that the fatigue crack propagation test was an effective method to investigate toughening and degradation of dental composites.

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] F. Takeshige et al.: "Fatigue Crack Growth Rate of Composites Determined under K-value controlled Test." Journal of Dental Research. vol75, Special Issue. 291 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] F. Takeshige et al.: "Fatigue Crack Propagation of Composites Resins in Water Environment." Journal of Dental Research. vol76, Special Issue. 77 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] F.Takeshige et al: "Fatigue Crack Growth Rate of Composites Determined under K-value controlled Test" Journal of Dental Research. vol 75, Special Issue. 291 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] F.Takeshige et al: "Fatigue Crack Propagation of Composite Resins in Water Environment" Journal of Dental Research. vol 76, Special Issue. 77 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] F.Takeshige,et al: "Fatigue Crack Growth Rate of Composites Determinedunder K-value controlled Test." Journal of Dental Research. vol75,Special Issue. 291 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] F.Takeshige,et al: "Fatigue Crack Propagation of Composite Resinsin Water Environment." Journal of Dental Research. vol76,Special Issue. 77 (1997)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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