Laboratory Evaluation of Toothbrushes
The primary objective of this study was to determine the stain removing ability of STAINO® toothbrushes.
The secondary objective was to evaluate the effect of the brush bristles on natural tooth enamel (safety evaluation).
MATERIALS AND METHODS
This was a standard laboratory evaluation performed on extracted stain bovine teeth and on extracted human teeth.
Twelve STAINO® toothbrushes were supplied. All brushes had the same bristle configuration, shape, size and length. Eight (8) brushes were used for the stain removal evaluation and four (4) brushes were used for the safety evaluation.
Eight (8) flat bovine enamel samples, which were stained according to the method described by Schemehorn, “In Vitro Removal of Stain with Dentifrices”, JDR (1982), were used for the stain removing evaluation of the study. Four (4) extracted human central incisors with broad, flat unrestored facial surfaces were used for the safety evaluation of the study.
The toothbrushing machine is modeled after an ADA standard design. The weight on each toothbrush head is 256 grams, and a speed of 180 reciprocal stroke cycles per minute was used. Water was used in all testing as a medium; no dentifrice was used in this evaluation.
All samples were evaluated at specific intervals: after 500, 1000, 2000, 5000 and 10000 brushing cycles. At each interval, the samples were visually evaluated for scratches and stain removal, and were also evaluated at 10X and 20X under a stereomicroscope. A Mitutoyo Surftest 401 Profilometer was utilized to determine surface roughness of the bovine and human enamel samples at each test interval. Digital images were taken using a Nikon Coolpix 800 digital camera to record any visual changes. A Minolta Chromometer CR-221 with a 1 mm diameter limited area attachment was used to quantify color changes during the progressive removal of the stain from each sample.
For the safety evaluation, one-half of each extracted natural tooth was protected with adhesive tape during the brushing in order to compare brushed vs. non-brushed areas for each tooth. The teeth were observed under a Hitachi Scanning Electron Microscope (SEM) for evidence of scratches produced by the brushes.
The Minolta Colorimeter measurements show a significant decrease in the amount of stain on the test bovine tooth enamel surfaces when brushed for 10,000 reciprocal strokes. The amount of stain removal was dependent on the level of initial stain: lighter stains were removed more significantly and sooner than heavier stains.
Examination of human enamel under the SEM (Scanning Electron Microscope) at 1000X magnification shows no adverse changes in surface condition (i.e., no scratches) after 10,000 brush strokes. The brushes do not abrade human tooth enamel to any measurable extent.
Studies conducted at:
New Jersey Dental School (UMDNJ)
110 Bergen Street
Newark, New Jersey 07103
July 31, 2003
by Marc A. Rosenblum, Ph.D., D.M.D.
Associate Professor of Dentistry
Department of General Dentistry and Biomaterials