A Question to sink your teeth into.

I went to the dentist to have a wisdom tooth removed. Getting the tooth out required breaking it into quarters and even then the dentist almost needed to kneel on my chest to get the leverage to get the first quarter of the tooth out.

Two weeks ago I went to the dentist because of the pain caused by one of my molars. X-rays were taken and it was advised that two other teeth on that side of my mouth also be removed. It proved necessary to drill into the bone to get the teeth out.

Today I went to the dentist to get the two teeth on the other side of my mouth that it was recommended be removed, pulled. Time and effort was required to get a piece of the root that broke off out. The piece was so firmly anchored into the bone that it broke off as the tooth was being pulled.

Which raises the Question: If my teeth are so attached to where they are and want to stay where they are as badly as the difficulties removing them suggests, why did the teeth allow the cavities that would necessitate removal?