About 20 years ago – already! – my dentist looked into my mouth and commented. “Ancient teeth. Our teeth get old than we do. Many of us are living far too long for our teeth. They were not designed to work after sixty years, or not so well. Now you may wish to floss, but it will make little difference. You will have troubles with these teeth like I do with mine. It is nearly inevitable. We carry ancient teeth you and I. Crumbling ancient teeth.”