Aims: The present in vitro study intended to investigate minimal erosive effects of different freshly squeezed fruit juices on human enamel during short time incubation by determination of calcium and phosphate dissolution.
Material and methods: Healthy adult human molars and premolars were cut in 160 blocks (5 mm x 6 mm x 2 mm) and divided randomly in sixteen groups of 10 samples each (n = 10). Each group was assigned for immersion at 37 oC in 5 ml juice, for different spot times 3, 6, 9 and 12 minutes, respectively. The freshly squeezed juices analyzed were orange juice, apple juice, orange mixed with carrot juice (1:1) and apple mixed with carrot juice (1:1). Amount of titratable acid and pH was measured for the tested solutions. Calcium and phosphate release were determined photometrically using VIS-UV/VIS spectrophotometer. ANOVA test compared the data generated (p < 0.05).
Results: The apple juice showing the lowest pH and a high value for buffering capacity had the most pronounced erosive effect. The orange juice was less erosive (p < 0.001). The least erosive was the orange mixed with carrots (1:1) (p < 0.001), which has the highest pH. The enamel demineralization increased when prolonging the immersion time (p < 0.0001).
Conclusions: All freshly squeezed juices caused the dissolution of calcium and phosphate in human enamel. Erosive capacity is mainly determined by pH and to a lesser extent by the buffering capacity. The amount of demineralization is directly correlated with the exposure time. Absorption spectroscopy allows detection of very small mineral loss using standardised human enamel samples.