In vitro demineralization of enamel by orange juice, apple juice, Pepsi Cola and Diet Pepsi Cola.

Enamel demineralization was studied over periods related to normal use of an orange juice, an apple juice, Pepsi Cola and Diet Pepsi Cola. Rectangular blocks of intact human enamel (3 mm x 3 mm) were cut from teeth, coated with nail varnish except for the enamel surface and exposed to the drinks for 2, 4, 5, 6 or 40 minutes. The amount of calcium released from the enamel into solution was determined with the use of an atomic absorption spectrophotometer. The results showed the following degree of enamel demineralization: Pepsi Cola = orange juice greater than apple juice greater than Diet Pepsi Cola. The results suggest that diet colas are less demineralizing than other acid drinks, and complementary plaque studies indicate that they are also less cariogenic. The study emphasized the importance of acid-type, buffer capacity, pH and the presence of other components on the degree of enamel demineralization.

The degree of enamel erosion by five different kinds of fruit.

It could be expected that the degree of enamel erosion by different fruits containing different kinds of organic acids, or different ratios of acids, and other different chemical components, will vary. The aim of this study was to investigate the degree of enamel erosion by different kinds of fruits (by determining the depths of enamel removed at different stages) over a period of 40 minutes. Statistically significant differences (p less than 0.05) were found among the slopes of apricot and that of grape, guava, apple, and orange. The results demonstrated that the degree of enamel erosion (etch depth) over a six-minute period had the following sequence: apricot more than grape and guava more than apple and orange; while over a 40-minute period the degree of etch depth was grape greater than apricot greater than guava greater than apple greater than orange. The degree of enamel erosion initiated by a fruit juice, as marketed, was about 5-8 times higher than that of the fruit (minced fruit juice). It also became clear that the degree of enamel erosion by different fruits depended on a combination of factors, such as the pH, amounts, and ratios, as well as the types of organic acids and other chemical components present in the fruits.