RESUMO
AIM: To evaluate and compare the in vitro pH, buffer capacity and calcium loss from tooth enamel before and after calcium fortification of a packaged fruit juice. METHODS: An approved brand of packaged mixed fruit juice was selected as a test drink on the basis of a pilot questionnaire. The test drink was fortified with 1,000 mg/l (0.1% w/v) of calcium citrate malate to obtain two test groups: Group 1: original beverage (serving as control) and Group 2: calcium-fortified drink. The pH and buffering capacity for the test drinks were measured before and after calcium fortification; 90 prepared enamel samples were divided and immersed into three test subgroups: (1) buffer solution pH 7 (positive control), (2) original fruit juice (negative control) and (3) calcium-fortified fruit juice for 3 min. Calcium loss from the enamel of immersed teeth was measured as a quantitative estimate of tooth mineral loss. RESULTS: After calcium fortification of the fruit juice the mean pH raised from 3.4 to 4.0 (p = 0.029), the mean buffer capacity decreased from 9.73 to 9.16 (p < 0.001) and the mean calcium loss from enamel specimens decreased from 3.5 to 0.26 mg/dl (p < 0.001). STATISTICS: To compare the change in mean pH and buffering capacity between the subject groups, t test was used, and to compare the calcium loss from enamel specimens, among the three subgroups, ANOVA was used. CONCLUSION: Calcium fortification of packaged fruit juice in vitro, improves its pH and buffering capacity. Consequently, the fortified juice causes significantly less mineral loss from human enamel. Fortifying juice with calcium may exert a significant protective potential against dental erosion particularly due to frequent exposure of acidic drinks.