Study on high-strength plastic teeth. Tooth discoloration.

Conventional plastic teeth (CV teeth) are inferior to porcelain teeth in maintaining an adequate esthetic appearance with wear and discoloration, and thus have a shorter period of durability. Recently, high-strength plastic teeth (HS teeth) have been developed and applied to overcome the wear problems of CV teeth. Since HS teeth made of hard resin are still susceptible to staining with pigments, it has been observed that the esthetics of removable partial dentures made from such plastic teeth are gradually impaired in many patients. To investigate the susceptibility of HS teeth to pigments, we conducted an in vitro study by immersing three types of artificial teeth in three coloring liquids. It was found that the HS teeth tended to be less susceptible to the test pigments than the CV teeth to various degrees. In contrast, they showed markedly stronger susceptibility to the pigments than porcelain teeth. For all three artificial tooth types, daily tooth cleaning with an ultrasonic vibrator had a tendency to reduce the coloration in comparison with their counterparts without ultrasonic cleaning.