Impact of Green Vegetables and Green Smoothies on Enamel Mineral Composition In Vitro

Background: Recently, smoothies with a high vegetable content have become very popular, especially among young adults. Objectives: This in vitro study was conducted to determine the erosive potential of selected green vegetables and green smoothies on human dental enamel. Methods: A total of ten green smoothies and eight freshly mixed vegetables were chosen, and pH, calcium and oxalic acid contents were measured. The enamel specimens were obtained from wisdom teeth and incubated with 3 selected foods (spinach, parsley, or green smoothie) for 12 and 24 hours (N = 6). Control samples were incubated with a physiological salt solution. An electron probe microanalyzer (Jeol JXA 8900RL) was utilized to analyze the concentrations of calcium, phosphorus, magnesium and fluorine at various depths ranging from 5 to 50 mwithin the enamel samples. A visual examination of the specimen was carried out with a digital microscope. Results: The green smoothies showed pH values ranging from 3.6 to 4.2, and the values of the mixed vegetables ranged from 5.6 to 6.3. Only in the green smoothie group could a time-dependent release of different minerals be observed. After 12 and 24 hours of incubation, a pronounced loss of calcium and phosphorus was found to a depth of 15m. Digital microscopy of the enamel surfaces confirmed these findings. Conclusions: In our in vitro study, incubation with the spinach and parsley showed no damage to the enamel specimens; in the case of the investigated smoothies, a mild loss of minerals to a depth of 25 mwas observed. It must be considered that numerous factors influence the enamel surface in vivo, translating these results to in vitro conditions must be done with great caution.