An international collaborative study of laboratory methods for assessing abrasivity to dentin.

An International Collaborative Study was conducted in which one surface profile and two radiotracer methods for assessing abrasivity of dentifrices on human dentin were compared. The study consisted of two phases: an open phase in which participating laboratories used the method they routinely practiced; and a controlled phase in which an expert team for each method performed the abrasion tests using all three methods. Four test pastes of known abrasivity were evaluated by each method. Similar abrasivity values for the test pastes were obtained with the radiotracer methods, whereas the surface profile method produced significantly different values. The precision levels of the radiotracer methods were similar, and both were superior to those obtained by the surface profile method. The time needed to perform the tests by the ADA radiotracer method was significantly less than that needed by the other methods. These findings suggest that the ADA radiotracer method will be useful in assessing abrasivity of dentifrices.