Modelling oral malodour from a tongue biofilm.

A new model about the genesis of malodour emanating from the tongue is introduced. A new approach uses mathematical formulae to combine existing empirical knowledge and bring it into context. The resulting description of halitosis includes the three-dimensional structure of the tongue dorsum surface as the substratum, and the transfer of oxygen and metabolites based on a four-dimensional partial differential equation solved by finite element analysis. The transport mechanisms of diffusion, flow, volatilization and chemical reaction are considered. The model predicts the majority of volatiles emanating from the back of the tongue at the end of a swallowing cycle, which correlates with empirical findings. Because the model is conceptual it allows greater freedom and precision than in vivo experimentation.