I was thinking about how we differ from crocodiles and sharks in terms of teeth. Now of course we don't have carnivore teeth but we also don't grow new teeth unless you are talking about a young child losing his/her baby teeth. But it seems like an omnivore diet, especially one that includes bones would be better suited to growth of new teeth than a carnivore diet.
I mean, there are all kinds of things that would wear down an omnivore's teeth. Here are just some of them:
Nuts and Seeds
And these 3 would wear an omnivore's teeth down the most, assuming no crispy processed foods are included.
And wouldn't wearing down of the teeth be a major factor into evolving the ability to grow new teeth?
So, since my Kepler Bb Humanoids are omnivores and they eat bones, especially during these circumstances:
And they don't get more frail with old age, why wouldn't they evolve to grow new teeth?