Thanks both of you for your input. The tooth isn't a "shell,"
it's still pretty strong. I'm investigating ways to build up the enamel on teeth. Calcium fluoride cell salt, Black-Walnut and comfrey are some of the things I'm using. Hopefully this along with OP and other things will help keep teeth in mouth. I'll know when the time is right to see a dentist again.
Mr. C, why did you have to extract that tooth? I've read that it is better to leave broken teeth in the mouth, since the root helps maintain the jawbone.