Although Coke caused the most staining OJ was the most acidic and caused demineralization of the shell. Brushing your teeth right after acidic drinks can wear away the enamel because the minerals have been taken away by the acid. Try drinking water to neutralize the acid and wait 30 min for the natural minerals of your saliva to help out before brushing. Using a fluoride mouth rinse or toothpaste helps to remineralize the enamel as well. Beer proved to be the least damaging to the enamel in this experiment! Brush and floss before bed because the bacteria in your mouth doubles every 8 hours...this will decrease the effect of that morning breath!