A new substance may counteract tooth decay under fillings and braces. According to Joseph M. Antonucci of the National Institute of Standards and Technology in Gaithersburg, Md., half of all fillings are replaced due to recurring decay. His team has developed polymer composites that dentists might someday place under fillings and behind orthodontic braces to heal small cavities.
The new substances carry calcium and phosphate ions inside polymers commonly used in dental applications. These ions can combine to make the stuff of teeth, the mineral hydroxyapatite (SN: 8/19/00, p. 122: http://www.sciencenews.org/20000819/bob1.asp). The new composites have already repaired decay in the enamel of cow's teeth in laboratory experiments, says Antonucci.