Laboratory studies on the chemical whitening effects of a sodium hexametaphosphate dentifrice

Laboratory studies were developed to permit the evaluation of chemical actions of toothpaste components in the non-abrasive prevention and removal of tea stains. Powdered hydroxyapatites were used as substrates for adsorption of tea chromogens. Pre-treatment with a sodium hexametaphosphate dentifrice (Crest Dual Action Whitening) reduced tea adsorption to powdered apatite, while post-treatments of pre-stained powder resulted in desorption of tea components. These results exemplified the chemical actions of condensed calcium phosphate surface active builders toward dental stain removal and prevention. A cycling synamel chip model permitted the study of stain prevention, including salivary pellicle formation and chlorhexidine enhancement of dental staining by tea chromogens. Staining was evaluated by image analysis of color development. Under these conditions, condensed phosphate dentifrices were observed to produce superior prevention of stain accumulations, with Crest Dual Action Whitening dentifrice providing stain prevention superior to a variety of commercial dentifrices, including Colgate Total, Aquafresh Whitening, Colgate Tartar Control Whitening, Mentadent Baking Soda and Peroxide Whitening, Close-Up Whitening, Crest Tartar Control and Crest Regular Cavity Protection.