The bactericidal potential of various endodontic materials for primary teeth.

An in vitro study of the bactericidal or bacteriostatic effects of several pulp therapy compounds and their components on selected bacterial commonly isolated from infected primary teeth was undertaken. It was determined that zinc oxide had no inhibitory effects on E. coli, Staph. aureus, and Strep. viridans; however, the addition of eugenol to this system retarded the growth of only the grampositive organisms. The inclusion of zinc acetate as a setting accelerator inhibited both gram-positive and gram-negative bacteria. Also the inhibitory effects on these three organisms could be greatly enhanced by the addition of formocresol or paraformaldehyde to the zinc oxide--eugenol--zinc acetate system. It was also noted that Sargenti's N-2 paste was apparently no more effective in retarding growth of these organisms than the mixtures. Only the lead tetroxide and hydorcortisone present in the N-2 paste was toxic to the Staph. aureus but not to E. coli or to Strep. viridans. The other heavy metals in N-2 apparently have no antibacterial activity in the manner in which they were tested. This evidence suggests, but is not conclusive, that zinc oxide--eugenol--zinc acetate, with or without formaldehyde-containing compounds, may be effective in the elimination of bacteria from pulpotomized primary teeth. Therefore, the addition of highly cytotoxic chemicals which will remain sealed in a root canal and be active for extended periods of time may not be necessary for successful treatment.