Analyses of biofilms accumulated on dental restorative materials

To qualitatively and quantitatively assess the architectural arrangement of microorganisms in biofilm developed on the surface of different restorative materials: ceramic (C), resin composite (RC), conventional (CGIC) and resin-modified glass-ionomer cements (RMGIC).

Streptococcus mutans was used to develop a biofilm that adhered to the surfaces of the selected material disks in 30 days. The specimens were stained and analyzed by confocal laser scanning microscopy and COMSTAT. Among biofilm properties, mean thickness, total bio-volume, roughness coefficient and surface-to-volume ratio were investigated, as well as characteristics of the distribution and architecture of viable/nonviable cells in the biofilm.

Only the mean biofilm thickness was statistically significantly different among the restorative materials tested. C and RC accumulated the thickest biofilms. Qualitative analysis showed cellular aggregates and fluid-filled channels penetrating to a considerable depth of the biofilm. In addition, images demonstrated a progression of more viable cells in superficial regions of the biofilm to proportionally more nonviable cells in the deeper regions of the biofilms near the disk.