Moderation of oral bacterial adhesion on saliva-coated hydroxyapatite by polyaspartate

Aims: Synthetic sodium alpha,beta-polyaspartate (PA) has been investigated as a moderator of adhesion and the subsequent biofilm formation by oral bacteria. Methods and Results: The inhibition of bacterial adhesion by PA was assessed by (i) a 30-min incubation with Streptococcus sanguis in a microtitre assay with the wells coated with hydroxyapatite (HAP) and (ii) an 18-h challenge with human salivary microflora in a HAP disc assay. In contrast to HAP-coated surfaces, clean polystyrene surfaces in the microtitre assay exhibited no anti-adhesion properties. It has been found that PA significantly and similarly adsorbs onto HAP surfaces in the presence and absence of salivary coating. The HAP disc assay also showed that PA, both in aqueous solutions and in toothpaste, reduced the level of adhered microflora and this effect was enhanced by added propylene oxide-ethylene oxide copolymers. Conclusion: The principal finding from this work is the potential role for PA as an inhibitor of dental plaque formation. PA may significantly modify the salivary pellicle. Significance and Impact of the Study: This work indicates the use of PA in controlling the development of dental plaque and the formation of bacterial biofilm in general.