Fluoride release for restorative materials and its effect on biofilm formation in natural saliva

This study investigated the influence of natural saliva of varying pH on surface biofilm formation of restorative materials and how this influenced fluoride release. Columnar specimens of glass ionomer cement (GIC), resin modified glass ionomer cement (RMGIC), compomer, giomer and composite, were prepared, matured for 24 h at 37 degrees C and 100% humidity, lapped and then placed in natural stimulated saliva with a pH of 3.8 or 7.1. Fluoride release was determined daily using an ion-selective electrode. The surfaces of selected specimens were observed using Confocal Laser Scanning Microscopy in conjunction with a fluorescent dye. The surface biofilm formation and bacterial growth was most dominant under neutral conditions and on the surfaces of GICs compared with other materials. GICs released significantly higher amounts of fluoride than other materials. The results suggest that the increased fluoride release of GICs did not reduce the amount of bacterial growth and biofilm formation on the surfaces of these materials when stored in natural saliva.