Strengthening of dental materials by compounding short glass fibers -Development of new dental cement

本研究的目的是确定具有特定长径比（长径比）的CaO-P_2 O_3-SiO_2-Al^2O_3（CPSA）玻璃短纤维是否可用作玻璃离子水门汀的增强剂，并阐明CPSA短纤维对玻璃离子水门汀弯曲强度的影响。在与玻璃离聚物粘固剂的液体混合之前，将商业玻璃离聚物粘固剂（未树脂改性）的粉末与各种尺寸的CPSA玻璃短纤维混合。含有60质量%的CPSA玻璃短纤维（直径; 9.7±2.1 m，长径比; 5.0±0.9）的混合粉末在24小时后分别获得固化水泥的径向拉伸强度（MPa）和弯曲强度（FS）的最大值18 Mpa和35 Mpa。这两个值分别为1.8和4。比不含短纤维的固化玻璃离子奥默水门汀大5倍。此外，发现添加CPSA玻璃短纤维在增强方面比电玻璃（典型的玻璃纤维）短纤维显著更有效。结果表明，由于短纤维的形状以及短纤维与混合液的反应性，CPSA玻璃短纤维起到了增强玻璃离子水门汀的作用。此外，随着在水中储存时间和热循环的增加，观察到玻璃离子水门汀（有或没有CPSA）的强度明显增加。热应力对含CPSA的玻璃离子水门汀的力学性能没有严重影响。含有CPSA的玻璃离子可保持较好的强度，因此，它可能是一种良好的材料，用于临床应用的骨水泥填充。

The purposes of this study was to determine if short fibers of CaO-P_2O_3-SiO_2-Al^2O_3 (CPSA) glass possessing a particular aspect ratio (length/diameter) could be used as a reinforcing agent for glass-ionomer cement, and to clarify the effect of the CPSA short fibers contained in the flexural strength of the glass-ionomer cement. The powder of a commercial glass-ionomer cement (not resin modified) was mixed with variously sized CPSA glass short fibers before mixing with the liquid of the glass-ionomer cement. The mixed powders containing 60 mass% CPSA glass short fibers (diameter ; 9.7±2.1 m, aspect ratio ; 5.0±0.9) obtained maximum values of 18 Mpa and 35 Mpa for the diametral tensile strength (DTS) and flexural strength (FS) of set cements, respectively, after 24 hours. These DTS and FS values were 1.8 and 4. 5 times larger, respectively, than those of the set glass-ion omer cement not containing short fibers. Moreover, it was found that the addition of CPSA glass short fibers was remarkably more effective in the strengthening than Electric glass (a typical glass fiber) short fibers. The results suggested that the CPSA glass short fibers acted as a reinforcing agent for strengthening the glass-ionomer cement, because of the shape of short fibers and reactivity between the mixing liquid and short fibers. Moreover an appreciable increase in strength with time stored in water and with thermal cycling was seen with glass-ionomer cement, with or without CPSA. Thermal stress did not have a serious influence on the mechanical properties of the glass-ionomer cement with CPSA. The glass-ionomer with CPSA may maintain better strength, and, thus, it may be a favorable material for clinical applications as cement for filling.