Abrasivity testing of dentifrices - challenges and current state of the art

Abrasivity potential of dentifrices is assessed mostly in vitro due to practical, scientific, and ethical reasons. The two most used evaluation methods are based on the measurement of radioactive dentin release or dentin surface profile changes, after simulation of toothbrushing with dentifrices. The radiotracer method known as radioactive or relative dentin abrasivity (RDA) was developed decades ago and is the most frequently used today (the 'gold standard' for many). The RDA is a reasonably robust method considered a useful tool for the determination of the relative abrasive level of dentifrices and abrasive powders. Studying the level of abrasivity of dentifrices under laboratory conditions is important to develop new formulations, to evaluate quality control of production, and to obtain a rough estimate of its potential clinical abrasivity. However, it is inappropriate to use RDA values alone to determine clinical safety when considering that dental wear is multifactorial and in vitro dentifrice abrasivity level is only one of the variables potentially affecting this outcome. It is important to remember that individuals present significant behavioral differences when brushing that could dramatically affect the potential of abrasion of a particular dentifrice. RDA values should be just one of the multiple variables being taken into consideration by professionals when providing recommendations to prevent dental wear.