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

点击翻译按钮获取中文摘要

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.