Biomechanical modelling of the caries-infiltration procedure of the photopolymer into the dental enamel

The study is devoted to the numerical investigation of the effectiveness of caries treatment by infiltration of the light-activated polymer into the caries-damaged enamel. The procedure of caries-infiltration is an advanced technology for treating of initial caries. As a result of enamel saturation with photopolymer, the progression of the disease stops. Due to the fact that the source of demineralization can be blocked even at the stage of caries initiation, it is possible to interrupt the caries development without mechanical damage of the enamel and without disruption of the natural structure of the tooth as a whole. In this paper, using the mathematical modelling and the application of the finite element analysis software package, the study of the infiltration method of caries treatment was carried out from the position of capillary phenomena on the basis of solving the problem of diffusion of a chemically reacting mixture in the “oral cavity-tooth-organism” system, which made it possible to determine the damage of solid tissues structure in the center of demineralization. Qualitative and quantitative estimation of the necessary parameters with functional interdependence was carried out with the help of numerical experiments on test models. Additional research allowed to us select the parameters under which the greatest physicality of the infiltration and the qualitative correspondence to the results of real process were observed. Some properties of the infiltrating polymer were obtained experimentally. The results of the calculations based on the constructed model reflect the pattern of the infiltration of the photopolymer as a function of both the polymer properties and the diversity of the volume distribution of carious damage in the porous structure of the enamel. In practice, this allows us to determine the time required for the infiltration of a zone completely encompassing the demineralized area, which is the criterion for evaluating the effectiveness of treatment by infiltration method.