Just knowing the biblical verses here one could predict a likely problem in the teeth area.
So produce 'em.
In evolutionary terms anything that doesn't cause a problem until after the age of reproduction won't get selected against. The prime example of this is Huntington's disease which is inherited in an autosomal dominant manner. It's fatal, yet it continues to be passed on because it only begins to manifest itself well after reproductive age, usually starting in mid forties. By the time someone knows they carry the gene the've already had children, 50% of whom will also carry it.
So we're stuck with our teeth that are prone to caries and awful abscesses. They can keep us going long enough to pass on these teeth to our offspring without modification.
As to why we don't grow more teeth underneath to replace bad ones, it seems to be something that would be selected against if it had ever happened or started to change. Our bite is very complex. Our teeth are a mixture of carnivore and herbivore and to work well together have a very small tolerance to any change in the size, angle or position of molar cusps. The top molars and bottom molars have to fit together well and all teeth are subject to the same wear so they still function with their partner. A new, unworn tooth appearing would cause havoc. I know this courtesy of an idiot dentist who filled a lower molar, but left the filling too high. The only place in my mouth where my teeth met was the raised filling and the molar above it. I spent a week on soup, none of my other teeth could function at all and even talking and swallowing were difficult. The thought of that happening on a regular basis as replacement teeth grow in makes me shiver.