Modeling the caries-inhibitory effects of dental materials.

The objectives of this review are to compare the models that are used to simulate the caries process in cardiology research and to suggest how these models might be used to assess caries-inhibitory properties of dental materials. Available caries-simulation models fall into the following classifications: 1) in vitro demineralization using acid buffers, 2) in vitro demineralization using bacterially generated acids, 3) in vitro demineralization/remineralization using a pH-cycling system, 4) an artificial mouth where a bacterially generated acid challenge is interspersed with a "saliva" treatment, 5) in vivo animal model (generally with rats), 6) in situ demineralization and/or remineralization using enamel or dentin blocks or slices in the human mouth, and 7) in vivo studies using teeth scheduled for extraction in the human mouth. Most dental materials studies have used simple in vitro demineralization models or component release experiments, each of which is inadequate to answer the questions that are being asked about the caries-inhibitory properties of the material being tested. Experimental methods must be chosen with care to ensure that the material to be tested is examined in an appropriate mode. The ultimate goal is to correctly predict clinical outcomes. The design or redesign of a model must eventually be tied to documented clinical outcomes to improve the model and allow for future successful development of new materials.