Tooth enamel is the hardest substance in the human body. But don’t let that fool you–it’s far from invincible. In fact, there are things you may be doing on a regular basis that weaken your enamel, which could lead to more frequent cavities, tooth discoloration and sensitivity. Tooth Enamel Acts As A Protective Barrier The enamel makes up the tooth’s protective outer layer and is the first line of defense against harmful acids and bacteria. Unlike other parts of the body, too