In silico study of hyposalivation and sugar exposure on biofilm dysbiosis

Dental caries develops under actively sugar-fermenting dental biofilms, but the most successful control methods available only target mineral loss. Reduced salivary flow rates (hyposalivation) significantly exacerbate caries progression by lessening sugar and acid clearance near tooth surfaces. Maintaining dental biofilm symbiosis (health) under hyposalivation requires knowledge of the impact of acid inhibition under given dietary regimens.

An individual-based mathematical model was used to predict biofilm dysbiosis under normal or hyposalivatory conditions by regulating the frequency of sugar intake and inhibiting microbial glycolysis, reducing the acid challenge to the tooth mineral. The impact of pH-dependent (stronger inhibition at lower pH [eg, fluoride]) and pH-independent (general percentage reduction in acid production) strategies on pH near the tooth surface during sugar intake, and the corresponding compositional changes in the biofilm, were quantified.

Under normal saliva flow, reducing the frequency of sugar intake and increasing the inhibition of acid production by pH-dependent or pH-independent strategies could prevent bacterial dysbiosis and prevent the biofilm from having a caries-associated (dysbiotic) to a health-associated (symbiotic) composition. However, under hyposalivatory conditions, dysbiosis occurred beyond 2 sugar intakes per day, and the degree of inhibition of glycolysis required to prevent dysbiosis was not feasible with available therapeutics.

Model data predict that to counteract the drastic effect of hyposalivation on biofilm dysbiosis, it will be essential to significantly reduce the frequency of fermentable sugar intake and any direct inhibition of bacterial metabolism.