Development of new composite resin for core build -up with similar machinability of dentin

本研究的目的是开发一种具有与人牙本质相同的可加工性的新型复合树脂。基质树脂采用BIS-GMA树脂。选用两种平均粒径为0.2m和4.3m的球形填料和一种平均粒径为6.6μm的异形混杂填料，硅烷化填料的质量分数分别为50%和80%。制备了3×3×25 mm的复合材料棒状试件。在40gf载荷下进行了可加工性试验，以体积磨削量来评价复合树脂的可加工性，平均粒径为4.3μm的球形填料的复合树脂磨削量大于使用不规则形状混杂填料的复合树脂的磨削量。在本研究所使用的复合树脂中，采用球形小填料的复合树脂研磨量最低。填料含量越高，研磨量越大，含50%小颗粒填料的复合树脂研磨量最低，与牙本质的研磨量相近。虽然复合树脂的可加工性与牙本质相似，但力学性能表现出较低的能力。必须改善复合树脂的性能，以满足堆芯使用。

The purpose of this study was to develop a new composite resin what has the same machinability with human dentin. Bis-GMA based resin was used for matrix resin. Two types of spherical-shaped fillers with average particle sizes of 0.2 and 4.3μm, and one type of irregular-shaped hybrid filler with average particle sizes of 6.6μm were selected.Silanized filler loadings were 50 mass % and 80 mass%. Bar-shaped specimens, 3x3x25 mm, of composites were prepared. The machinability was evaluated as a volumetric grinding amount after a machinability test at a 40-gf load.The grinding amount of composite resin using the spherical-shaped filler with average particle sizes of 4.3μm was greater than those using the irregular-shaped hybrid filler. The composite resin using small spherical-shaped filler was the lowest grinding amount among the composite resins using in this study. The grinding amounts were greater when the filler content was higher.The grinding amount of the composite resin included 50 mass % small sphericalshaped filler was the lowest, and similar to that of dentin. Although the machinability of composite resins were similar to that of dentin, mechanical properties of these composite resins show low ability. Improvements of composite resin properties must be done for core build-up usage.