
When I had a problem with a toothache, a reader wrote in to offer advice about a product that she uses to help strengthen her teeth.She wrote:"Here's a suggestion buy a bottle of Glycerin. Either the '100% pure Vegetable Source' from a health supplement store, or a drugstore's 'USP' grade is fine. Brush your teeth with it, pure. It is a moderately sweet, intensely hygroscopic 3-carbon alcohol, somewhat syrupy in texture. You can swallow it, if you wish. In fact, a swish on the back of the tongue...