ANTIBACTERIAL ACTION OF CERTAIN FLUORIDE-CONTAINING DENTAL RESTORATIVE MATERIALS

¹ Departments of Microbiology and Dental Materials, Indiana University School of Dentistry, Indianapolis, Ind.

The antibacterial effects of certain fluoride-containing dental materials against 7 different microorganisms have been investigated. The powders, liquids, plastic and hardened pellets of the materials were all studied.

These data indicate that the addition of low concentrations of fluorides to resins or zinc phosphate cement will not inhibit growth of the microorganisms here tested. Certainly, the results of this study give increased support to the theory that the lower incidence of recurrent caries associated with the silicate restoration is due to decreased solubility of the tooth structure which is in opposition to the restoration.

The materials listed in decreasing order of their antibacterial action in the plastic state were the two commercial silicates, zinc phosphate cement containing 5.0 per cent calcium fluoride, a commercial zinc phosphate cement, and resins containing fluoride. Addition of sterile horse serum or human saliva to the medium produced variable results. There was no inhibition of bacterial growth on transfer of the pellets to freshly inoculated plates. Likewise, no effect was observed when the hardened pellets or cement powders were used. Mixing fluids containing phosphoric acid were strongly antibacterial whereas the resin liquid was ineffective. The implications of these results have been discussed.