Is enamel the smartest dental material?

At the dental school, the structure of enamel is taught in great detail, but has anybody ever explained why enamel has its wonderfully unique structure? Before I go there, let's remind ourselves about the functions of enamel. It is there to cut, tear and grind the food to aid digestion. It does this very effectively, and if you look after your teeth, they will last you a lifetime. No such claim can be made for any of the dental materials we use to replace enamel. They are always second best. And yet enamel is not a strong material, it has been reported to have a flexural strength in the region of 30–50MPa. This contrasts with zirconia where strengths can reach into four figures. So what is it that makes enamel such a durable material? In order to answer that question, we have to look at enamel, not from its biological or chemical perspective, but from an engineering perspective.