Willems G, Lambrechts P, Braem M, Vanherle G
Department of Operative Dentistry, Dental Materials, Catholic University of Leuven, Belgium.
Quintessence Int. 1993 Sep;24(9):641-58.
Human enamel and dentin should be used as the physiologic standards with which to compare composite resins, especially in the posterior region. The intrinsic surface roughness of composite resins must be equal to or lower than the surface roughness of human enamel on enamel-to-enamel occlusal contact areas (Ra = 0.64 microns). Roughness determines the biologic strength of composite resins. The nanoindentation hardness value of the filler particles (2.91 to 8.84 GPa) must not be higher than that of the hydroxyapatite crystals of human enamel (3.39 GPa). Composite resins intended for posterior use should have a Young's modulus at least equal to, and preferably higher than, that of dentin (18.500 MPa). The compressive strength of enamel (384 MPa) and dentin (297 MPa) and the fracture strength of a natural tooth (molar = 305 MPa; premolar = 248 MPa) offer excellent mechanical standards to select the optimal strength for posterior composite resins. The in vivo occlusal contact area wear rate of composite resins must be comparable to the attritional enamel wear rate (about 39 microns/y) in molars. Differential wear between enamel and composite resin on the same tooth is a new criterion for visualizing and quantifying the wear resistance of composite resins in a biologic way. Posterior resins must have a radiographic opacity that is slightly in excess of that of human enamel (198% Al). Based on these standard criteria, it can be concluded that in the 21st century the ultrafine compact-filled composite resins may be the materials of choice for restoring posterior cavities.
人体牙釉质和牙本质应用作生理标准，用以比较复合树脂，尤其是在后牙区域。复合树脂的固有表面粗糙度必须等于或低于人体牙釉质在釉质与釉质咬合接触区域的表面粗糙度（Ra = 0.64微米）。粗糙度决定了复合树脂的生物强度。填料颗粒的纳米压痕硬度值（2.91至8.84吉帕）不得高于人体牙釉质的羟基磷灰石晶体的硬度值（3.39吉帕）。用于后牙的复合树脂的杨氏模量应至少等于牙本质的杨氏模量（18500兆帕），最好高于牙本质的杨氏模量。牙釉质（384兆帕）和牙本质（297兆帕）的抗压强度以及天然牙（磨牙 = 305兆帕；前磨牙 = 248兆帕）的断裂强度为选择后牙复合树脂的最佳强度提供了优良的力学标准。复合树脂在体内的咬合接触区域磨损率必须与磨牙中牙釉质的磨耗率（约39微米/年）相当。同一颗牙齿上牙釉质与复合树脂之间的差异磨损是以生物学方式可视化和量化复合树脂耐磨性的新标准。后牙树脂的射线不透性必须略高于人体牙釉质的射线不透性（198%铝当量）。基于这些标准，可以得出结论，在21世纪，超细致密填充复合树脂可能是修复后牙洞的首选材料。
