Anti-biofilm Effects of Glass Ionomer Cement Containing BioUnion Filler

Objectives: Previously, we reported that glass ionomer cement incorporating BioUnion filler (Caredyne-Restore, GC) demonstrated acidity-induced release of zinc ion and could inhibit growth of oral bacteria on its surface. The aim of this study was to evaluate inhibitory effects of Caredyne-Restore against bacterial adherence and biofilm formation by in vitro and in situ tests.
Methods: Disc specimens were prepared using Caredyne-Restore and immersed in Streptococcus mutans suspension at 10⁶ CFU/mL supplemented with sucrose. After anaerobic incubation for 24 hours, the bacteria attached onto the specimen surface were collected and their number was counted by the plating method. For evaluation of inhibitory effects against biofilm formation, the disc specimens were fixed in the region of upper premolars and molars of 4 volunteers using a custom-made acrylic splint. The specimens were collected after 24 hours, and the biofilm formed on the surface was observed and analyzed by using a confocal laser scanning microscopy with LIVE/DEAD staining. The number of viable bacteria in the biofilm was determined by colony counting. For comparison, a conventional glass-ionomer cement (Fuji VII, GC) and a resin composites (MI Fil, GC) were tested.
Results: The number of S. mutans attached on the Caredyne-Restore was significantly less compared with those on Fuji VII and MI Fil (p<0.05, ANOVA, Tukey’s HSD test, n = 3). The image analysis revealed that in situ biofilm formed on the Caredyne-Restore was significantly thinner than Fuji VII and MI Fil (p<0.05, ANOVA, Tukey’s HSD test, n = 4). The number of surviving cells in the biofilm formed on the Caredyne-Restore was significantly lower than that of Fuji VII and MI Fil (p<0.05).
Conclusions: The glass-ionomer cement containing BioUnion filler demonstrated the effects to prevent adherence of oral bacteria and was effective to inhibit biofilm formation on its surface.