Wassell R W, McCabe J F, Walls A W
Department of Dental Materials Science, University of Newcastle upon Tyne, England.
Dent Mater. 1992 Jul;8(4):218-23. doi: 10.1016/0109-5641(92)90088-t.
This study was prompted after a series of composites had been hardness-tested with the Vickers (pyramidal diamond indenter) and Barcol tests (flat-ended steel cone indenter). The results were found to differ markedly from the supplied Barcol/Vickers conversion chart. A sectioning and silver staining technique was therefore developed to examine the modes of subsurface deformation of four composites under the two indenters. Under the Vickers indentations, the large particle hybrid, Occlusin, showed a clear hemispherical area of subsurface disruption while the small particle hybrid, Brilliant Dentin, had a less distinct zone of disruption. The microfilled materials, Heliomolar and Isosit, showed minimal silver uptake, suggesting a less disruptive mode of plastic deformation. Under the Barcol indentations, Occlusion and Brilliant Dentin produced clear hemispherical zones of deformation, while Heliomolar and Isosit were badly crazed with distinctive patterns of subsurface flaws. These consistent patterns of failure to some extent explain the comparison of hardness measurements and may be of use in explaining the wear mechanisms of composite restorations.
在使用维氏硬度测试（金字塔形金刚石压头）和巴氏硬度测试（平头钢圆锥压头）对一系列复合材料进行硬度测试后，引发了本研究。结果发现，测试结果与所提供的巴氏硬度/维氏硬度换算表有显著差异。因此，开发了一种切片和银染技术，以研究在两种压头作用下四种复合材料的亚表面变形模式。在维氏压痕下，大颗粒混合材料Occlusin显示出明显的亚表面破坏半球形区域，而小颗粒混合材料Brilliant Dentin的破坏区域则不太明显。微填料材料Heliomolar和Isosit显示出极少的银吸收，表明其塑性变形的破坏模式较小。在巴氏压痕下，Occlusion和Brilliant Dentin产生了明显的半球形变形区域，而Heliomolar和Isosit则出现了严重的裂纹，并伴有独特的亚表面缺陷模式。这些一致的破坏模式在一定程度上解释了硬度测量结果的比较，可能有助于解释复合修复体的磨损机制。
