The science behind caries prevention.

Many agents have been shown to have an anticaries effect or to have the potential for such an effect. They can be categorised by their modes of action into three groups: those which affect plaque and plaque bacteria, those which affect tooth enamel chemistry and those which buffer oral pH. To be effective clinically, agents must not only possess intrinsic efficacy but also good oral retention characteristics. Currently, chlorhexidine is arguably the only antibacterial agent to have inhibited caries in humans, but is not employed in anticaries dentifrices and mouthrinses intended for long-term unsupervised daily use because of formulation difficulties and undesirable side effects such as tooth stain. Certain calcium salts and xylitol may also exert some clinical effect. The only extensively clinically-proven agent is fluoride. Well established reasons for the success of fluoride are its abilities to inhibit demineralisation of enamel and to enhance the remineralisation of incipient caries lesions. Recent research has highlighted the persistence of fluoride in saliva and plaque at potentially-active concentrations between successive regular applications of dentifrices and mouthrinses as a further important mechanistic step. Oral fluoride retention studies can explain recent clinical observations of increased efficacy of sodium fluoride dentifrices compared with sodium monofluorophosphate dentifrices of equivalent fluoride content.