2012 Fiscal Year Final Research Report
Study of zirconia surface modification by femto-second laser.
| Project/Area Number |
23659895
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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 |
Prosthetic dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
MOTOMURA Kazuo 東京医科歯科大学, 医歯(薬)学総合研究科, 助教 (60272598)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Shigekazu 静岡大学, 工学部, 教授 (60197423)
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| Project Period (FY) |
2011 – 2012
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| Keywords | 歯科補綴学一般 |
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| Research Abstract |
We modified the surface of zirconia dental prostheses through femto-second laser process in order to improve the adhesion strength of them. In this study, two alignments of linear micro-grooves were employed on the surface. The increase of adhesion shear strength and the effect of the alignment on the strength were examined. A round end surface of a fully-sintered zirconia bar with diameter of 5mm was processed with femto-second laser system, which provided pulse energy of 9μJ and spot feed of5μm/pulse. Through the process, micro grooves with depth of 51μm and width of 53μm were obtained. In this study, two types of alignments in linear grooves were produced. In the first alignment, straight groove lines were parallel. In the second, two groups of parallel grooves were perpendicular to each other.The modified zirconia surfaces were bonded to the mirror surface of Crearfil DC Core Auto-mix ONE (Kuraray Medical Inc.,Japan) to which the surface of a glass slide was transferred. The adhesion used was Crearfil SA Cement Auto-mix universal (Kuraray Medical Inc.,Japan). The thickness was 50μm and the diameter of round bonded area was 4mm. Adhesion shear strength tests were carriedout on the universal testing machine(DCS-5000, Shimazu Co.), in which the speed of cross head was 1mm/min.The adhesion shear strength of zirconia surface with linear parallel microgrooves was35.8(S.D.:6.0) MPa, while the strength of original surface without grooves was23.4(S.D.:9.2) MPa. Moreover, the strength of the surface with cross-typed microgrooves increased up to 46.8(S.D.:5.5) MPa. The surface modification through femto-second laser process, in which micro-grooves were formed on it, is very useful tool for improving the adhesion strength between zirconia prostheses and cements.
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