Our primary teeth, sometimes called baby teeth or milk teeth, are usually gone by 12 years of age. Our permanent or "adult" teeth are meant to last for the rest of our lives. Unfortunately, as a result of dental caries, periodontal disease, or trauma, some teeth don't last as long as the adult to whom they are attached!
Replacing lost teeth with bridges, dentures, or implants is expensive and time-consuming, and, despite incredible dental materials and cosmetic advances in recent years, results may not be as good as nature's own. If only we had a third chance ...
Two reports in the July issue of the Journal of Dental Research highlight exciting advances in moving toward the tissue engineering of teeth. At The Forsyth Institute (Boston, Mass.), Pamela Yelick and colleagues have seeded cultured rat tooth germ cells on biodegradable scaffolds which were then implanted to bioengineer tooth tissues, while in London (UK), Paul Sharpe's group has been able to generate mouse tooth structures from non-dental mesenchymal stem cells placed in contact with embryonic oral epithelium. (Mesenchymal cells are uncommitted cells that can later develop into connective tissue, blood vessels, or lymphatic tissue.)
The latter report is pivotal in that it demonstrates that mesenchymal stem cells, in association with oral epithelium, can be instructed to mimic developmental events leading to growth of a tooth structure comprised of enamel, dentin, and pulp, with a morphology resembling that of a natural tooth. These observations offer very exciting opportunities for replacement of natural teeth damaged through disease or trauma. In addition, there may be applications in some rare genetic diseases, like ectodermal dysplasia, that result in congenitally missing teeth ("hypodontia"). There are obvious practical obstacles still to be overcome before this might be available as a routine clinical treatment, but it provides an elegant example of the translation of basic science research to the clinical arena.
There are also significant opportunities in the shorter term to exploit this knowledge for the development of novel regenerative therapies which seek to restore tooth structure lost due to dental caries. Rather than a traditional amalgam or composite "filling," the new tissue would become an integral part of the tooth, thus avoiding many of the problems of failure associated with more traditional fillings.
Clearly, the future for regenerative and tissue-engineering applications to dentistry is one with immense potential, capable of bringing quantum advances for the benefit of patients. The need for high-quality research in the basic sciences is paramount to ensuring the development of these novel clinical treatment modalities. This research illustrates how dentistry is evolving and highlights the need for close partnerships between basic and clinical scientists.
The Journal of Dental Research (est. 1919) is the most-cited dental journal in the world and is the flagship publication of the International Association for Dental Research, established in 1920 to promote research in all aspects of oral and related sciences, to encourage development of improved methods for prevention and treatment of oral and dental diseases, and to facilitate cooperation among investigators and communication of research findings and their implications throughout the world. The IADR, a non-profit organization, has over 11,000 active individual members and over 100 institutional members worldwide.