The effect of dilution on the in vitro erosive potential of a range of dilutable fruit drinks

Background.  Only one previous study has investigated the effect which dilution has on the erosive potential of dilutable fruit drinks. Based solely on measurement of neutralizable acidity, the authors concluded that the erosive potential of diluting juices may be reduced substantially by the addition of water. This has not been verified in an in vitro enamel erosion model. Objective.  The aim of this study was to examine the effect of dilution on the erosive potential of five dilutable fruit drinks. Methods.  For each product, the erosive potential of three dilutions (1 : 3, 1 : 6 and 1 : 15) was assessed by measuring the initial pH and neutralizable acidity; in vitro enamel erosion was measured by profilometry following immersion for 1 h. Results.  For the majority of products, increasing dilution from 1 : 3 to 1 : 15 produced a statistically significant rise in initial pH, though they remained markedly acidic. Increasing the dilution factor consistently produced a statistically significant decrease in neutralizable acidity. Increasing the dilution factor from 1 : 3 to 1 : 15 produced a statistically significant reduction in in vitro enamel erosion in only three of the five products tested. Conclusions.  Increasing the dilution factor of dilutable fruit drinks within a range likely to be acceptable to the consumer may not effectively reduce their erosive potential.