The etched depth profile of enamel surface was tested by SEM and digitized by image analysis to detect the roughness of enamel. And the fractal dimension could quantify the roughness.

Very few whitening toothpastes have undergone any type of clinical trial, and ones that are too abrasive can damage teeth or make them very sensitive.

To evaluate the effectiveness (versus a placebo or another active product) and side effects of over-the-counter or dentist-dispensed chemically-based tooth whitening products designed for home use.