Abstract
The purpose of this study was to investigate the characteristics of the newly developed set paste/paste type light-cured restorative glass-ionomer cement “FujiFil LC”. The glass-ionomer cement was improved in transparency after light curing and in the mixing procedure. The interfacial ultra-structure between the glass-ionomer cement and human enamel/dentin was observed using SEM. The characteristic potential of fluoride-release and uptake of FujiFil LC was also determined. In addition, to investigate the recharge effect of fluoride on glass ionomer cements, specimens (9 mm diameter x 1 mm in height) were immersed in 9000 ppm NaF solution for 5 minutes. Moreover, diametral tensile strengths test of the specimens (6 mm dia.×3 mm thick) kept for 24h and 30 days in distilled water were undertaken in order to compare the strength of Fuji IX GP and Fuji II LC.
Results demonstrated that the glass ionomer cement-tooth junction was very tight showing no gap formation adjacent to the enamel and dentin, while a hybrid layer like structure about 1 um in thickness was observed at the superficial dentin on FujiFil LC. The highest fluoride ion release was shown after one day in all of the freshly-mixed specimens, and the release rates dropped quickly to become stabilized at 3 days. After 5-min exposure to a 9000 ppm NaF solution the initial fluoride ion release significantly increased for all materials. The highest rates were during the first day, but then dropped very quickly to become again stabilized in 3 days. The order of fluoride release and uptake for FujiFil LC was higher than those of Fuji II LC and a conventional glass-ionomer cement Fuji IX GP. In the tensile strength of tested specimens, there was no significant difference in diametral strengths between 24h and 30 days specimens for each material. FujiFil LC glass-ionomer cement can clinically achieve satisfying aesthetic dental restoration.
