If you are one of those people who like to have orange juice in the morning just after they have brushed their teeth, you probably know how bad that tastes. Drinking orange juice after brushing your teeth brings about a very repulsive taste in the mouth. If you haven’t tried that, try it once. Trust me, toothpaste + orange tastes awful.
Water, fluoride, detergent and abrasives are the four major components of toothpaste. And the most common detergent (used to form foam) is called Sodium Lauryl Sulphate, or SLS. SLS has some strange effects on your taste receptors. It suppresses the receptors which help you taste sweet
Also, it destroys a compound called phospholipid – compounds meant to suppress the bitter taste. These are the two accepted reasons as to why drinking orange juice after brushing your teeth is probably a bad idea.