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THREE RECENT NATIONAL surveys have emphasised the extremely high prevalence of dental caries in Britain (Gray et aL, 1970;Todd & Whitworth, 1974;Todd, 1975). F#.>r example, 71 per cent of five-year-old children have teeth that are decayed or that have been filled or extracted; in eight-year-olds the figure is 91 per cent and in 15-year-olds 97 per cent. The average number of affected teeth in five-year-olds is 3.4, in eight-year-olds 5.0, and in 15-year-olds 8.4. No less than 37 per cent of the adult population in England and Wales have no natural teeth, and in Scotland the figure is 44 per cent.

It is generally accepted that carbohydrate foodstuffs retained in the mouth and around the teeth provide the substrate for the bacterial action which results in the formation of the acids associated with dental caries. It is also recognized that some carbohydrate foodstuffs may be more important than others in this respect. Previous workers have suggested that the greater the amount of acid produced by a food during fermentation, the greater might be the effect on enamel. Thus Bibby, Goldberg, and Chen' used the acid-production property (along with a food-retention factor) to obtain decalcification potentials of a large variety of foods. Later Ludwig and Bibby2 found that some foods having a high decalcification potential produced lower plaque pH values than did foods having a low decalcification potential. However, it has not been shown whether foods producing large amounts of acid actually have the power to cause greater enamel decalcification than foods producing less acid.In other experiments the decalcification of enamel in food-saliva mixtures has been studied but not related to the amount of acid produced by the foods. For example, Osborn, Noriskin, and Staz3 examined macroscopically the surfaces of whole, noncarious teeth for signs of decalcification, while Jenkins, Forster, Speirs, and Kleinberg4' 5 measured the increase of calcium and phosphorus in mixtures containing powdered enamel and later substituted calcium phosphate for the powdered enamel. Both these groups of workers found differences in enamel decalcification after incubating crude and refined carbohydrates in saliva which could not be explained on the basis of pH. However, in neither study was an actual titration made of the acid produced by the food-saliva mixtures, so that no relationship could be seen between total acid production and enamel decalcification.Thus some previous workers found differences in the amounts of acid produced by various foods in saliva but did not relate these to effects on enamel, while others showed differences in enamel decalcification but did not relate them to differences in acid production. The primary purpose of the present study, therefore, was to demonstrate whether there exists a direct relationship between the amount of acid produced by salivary fermentation of carbohydrate foods and the amount of accompanying enamel decalcification.The author is the recipient of the Edward H. Hatton Award for 1960, which was presented at the thirty-eighth general meeting of the I.A.D.R.

The caries-preventive effects of two toothpastes were tested in a 3-year clinical trial involving 1319 children aged 11-13 years. The test toothpastes were: 1) a low abrasion paste containing 0.8% sodium monofluorophosphate (MFP), and 2) a paste containing 3% sodium trimetaphosphate (TMP). The control toothpaste was a conventional, moderately abrasive paste containing 0.8% sodium monofluorophosphate. The children were examined clinically and radiologically each year. Toothpaste was supplied to the children's homes, and its use was unsupervised. Caries increments after 3 years, in terms of DMF teeth and DMF surfaces, showed no significant differences between the MFP test group (444 children) and the MFP control group (450 children). However, the TMP test group (425 children) had significantly higher caries increments than the MFP control group. All three groups of children showed some improvement in oral hygiene and in gingival health, but there were no significant differences between the groups.