Trivia: What is the hard coating on teeth called?
Collagen
Enamel
Fibrosis
Ischium
The correct answer is Enamel
So why is this answer correct? : Enamel, the outer coating on teeth, is mostly made up of hydroxyapatite, a substance even harder than bone. Enamel serves to protect the teeth from physical and chemical damage, and as a result is prone to wear and tear. Enamel erosion can lead to symptoms such as tooth stains and sensitivity.