Methods: Labial crown surfaces of 27 anterior human teeth were treated with Coca-Cola for 30 minutes, followed by one of nine different products for 30 minutes: filtered water, fluoride rinse, skim milk (30% Ca, 25% vitamin D), 2% milk (30% Ca, 25% vitamin D), whole milk (30% Ca, 25% vitamin D) chocolate milk (30% Ca, 25% vitamin D), lactose-free milk (50% Ca, 25% vitamin D), almond milk (45% Ca, 25% vitamin D), and soy milk (45% Ca, 30% vitamin D). Three teeth were used for each treatment and enamel microhardness of each sample was assessed at baseline pre-treatments, after the 30-minute erosion treatment, and after the 30-minute post-erosion treatment.
Results: All tested agents resulted in significant increases in enamel microhardness after erosion to levels compared to baseline (p<0.05). Significant differences of microhardness were observed between filtered water in comparison to fluoride rinse (p=0.02), skim milk (p=0.04), 2% milk (p=0.04), whole milk p=0.02), lactose-free milk (p=0.02), and soy milk (p=0.03). There were no differences in post-treatment microhardness between fluoride rinse and the various milks. Differences in microhardness were significant between skim and whole milks (p=0.002), skim and lactose-free milks (p=0.008), skim and soy milks (p=0.019), 2% and chocolate milks (p=0.04), whole and chocolate milks (p=0.02), whole and almond milks (p=0.045), chocolate and lactose-free milks (p=0.05), chocolate and soy milks (0.027), and almond and soy milks (0.029).
Conclusions: Filtered water, fluoride rinse, and varying milks all result in remineralization of enamel after erosion. There were no significant differences in post-treatment microhardness between fluoride rinse versus the milks. Fluoride rinse, skim, 2%, whole, lactose-free, and soy milks have a significant greater gain of enamel microhardness as compared to filtered water, chocolate milk, and almond milk.