HOW ABRASIVE NEED A DENTIFRICE BE?

¹ College of Dentistry, Ohio State University, Columbus, Ohio

Stained pellicle is not produced by liquid dentifrices, but results from accumulation of stain on the teeth of certain individuals using water or other nonabrasive dentifrices. The degree of staining is an individual characteristic.

Using groups of dental students who were heavy stainers with brush and water, we determined staining of their teeth while they were using a series of commercial dentifrices of different degrees of abrasiveness. These dentifrices varied from water, which is practically nonabrasive when applied with crossbrushing to the cervical areas of teeth, to a commercial tooth powder capable of cutting a notch 4 mm. deep with 100,000 strokes.

Dentifrice abrasiveness greater than that necessary to cut 1 mm. per 100,000 strokes into the cervical area of teeth with the apparatus employed, appears to be unnecessary even for very heavy stainers who would not constitute more than 20 per cent of a population. Only one of the commercial paste dentifrices tested was excessively abrasive for heavy stainers. The commercial powders tested, with one exception, were from 100 per cent to 300 per cent more abrasive than was found necessary to accomplish stain prevention in our tests on heavy stainers.

Generally speaking, for stainers with cervical exposure, a dentifrice with a safety index as high as is consistent with prevention of stain accumulation is desirable. Such a dentifrice should be determined on an individual basis.

Dentifrice abrasion, for obvious stainers, will be a necessary evil until a nonabrasive, stain-removing or preventing agent is found. Reliable current information on dentifrice abrasion, determined by testing whole dentifrices on dentin, should be available.