Saliva-Activated Nanohybrid Aggregates Are Rapid-Acting Agglutination Agents with Potent Anticaries Activity and Limited Toxicity

Dental caries is a multifactorial process attributed to a diet high in fermentable carbohydrates, tooth-adherent plaque comprising acidogenic microbes (Streptococcus mutans), and a host of associated risk factors. We previously reported a nanohybrid aggregate formulation comprising nanoceria (CeO₂-NP) and chondroitin sulfate A (CSA) that limited sucrose-dependent biofilm formation of S. mutans via the induction of nonadherent cell clusters. Herein, we report the chemical and bioactivity analysis of CeO₂-NP-CSA and a related derivative (CeO₂-NP-CSA-B) in a series of preclinical studies culminating in both in vivo efficacy and toxicity studies. Time-dependent sedimentation assays and dynamic light scattering studies in whole human saliva model systems demonstrate changes to aggregate size/zeta potential (activation) of both CeO₂-NP-CSA and CeO₂-NP-CSA-B that correlate with the rapid clearance of S. mutans. Further, CeO₂-NP-CSA-B was found to significantly inhibit tooth-retained rodent plaque and dental caries, similar to an over-the-counter anticaries mouth rinse. Human cell toxicity and maximum tolerated dose studies provided no significant evidence of toxicity of CeO₂-NP-CSA-B as quantified in a series of well-known clinical chemistry and hematological assays. This study summarizes the chemical and biological data supporting the potential of nanohybrid aggregate formulation(s) as future caries prevention agents.