We take them for granted until they are gone or require major repairs. And then the options are grim: do without lost teeth or replace them with inert prosthetic versions. In the Western world, an estimated 85 percent of adults have had some form of dental treatment. Seven percent have lost one or more teeth by age 17. After age 50, an average of 12 teeth stand to have been lost.
In theory, a natural tooth made from the patient's own tissue and grown in its intended location would make the best possible replacement, although such bioengineered teeth have for many years been little more than a dream. Recently, however, progress in understanding how teeth first develop has combined with advances in stem cell biology and tissue engineering technology to bring us close to the realization of biological replacement teeth.