Effect on plaque pH of fruit drinks with reduced carbohydrate content

To assess the acidogenic response in dental plaque after challenge with four fruit drinks, including two blackcurrant drinks newly formulated, with low levels of carbohydrate.

24 adult volunteers rinsed, in randomised order, with each of two new formulations of a blackcurrant drink (7% juice with 0.49% and 10% juice with 0.65% carbohydrate concentration respectively), an apple and blackcurrant drink with no added sugar (0.8%), and a mixed citrus fruit drink with a higher carbohydrate concentration (4.5% w/v). Solutions of 10% sucrose and 10% sorbitol were used as controls. Plaque pH was assessed, in vivo, before and after the acidogenic challenge using the plaque-harvesting technique.

Results showed that the minimum plaque pH after the subjects rinsed with the new blackcurrant drinks was higher as compared with all the other test products and significantly so compared with the mixed citrus drink (P = 0.0001). It was also found that with the 7% blackcurrant juice drink none of the subjects and with 10% blackcurrant juice drink only one subject recorded a pH drop below the pH of 5.7. Ten minutes after consumption, both the new formulation blackcurrant drinks produced significantly higher plaque pH than the mixed citrus drink. In addition, overall change in the hydrogen ion concentration over the study period (sigma delta cH) was significantly less with both new blackcurrant drinks compared with the mixed citrus drink.

It was concluded that the two new formulations with low levels of carbohydrate had a low acidogenic potential and did not depress the plaque pH below the critical level and their consumption could not be considered to pose a significant risk for enamel demineralisation.