A Comparative Study of Laboratory Dentifrice Abrasion Measuring Methods.

OBJECTIVES: Recently, a profilometry-based method for measuring toothpaste dentin abrasivity has been proposed to be equivalent to the traditional radiotracer RDA (relative dentin abrasion) procedure. This review outlines the findings and comparative assessment of laboratory studies used to measure the abrasivity of commercially available whitening dentifrices on human dentin. Traditional radiotracer and profilometry RDA-PE (Profilometry Equivalent) methods were assessed, with the objective of determining how they compare, and also to learn if the two techniques yield RDA values that are consistent with each other, specifically in ranking and potential for discrimination of three commercially available silica-based products. Chosen were regular toothpaste and two whitening dentifrices having abrasive properties against dentin ranging from medium to high. METHODS: Dentin specimens underwent standard preparation, preconditioning, and abrasivity testing according to the ISO 11609 requirements for radiotracer method and RDA-PE. Three test dentifrices were used, each product containing various abrasive and polyphosphate agents, namely: Whitening Product A: Hydrated silica with disodium pyrophosphate (Crest® 3D Luxe); Product B: Hydrated silica (Crest® Cavity Protection); and Whitening Product C: Hydrated silica with tetrasodium pyrophosphate (Colgate® Ultrabrite Advanced Whitening). The products were chosen since they gave a range of RDA values from mid to high when compared with an ADA reference material that is given a value of 100. RESULTS: The data were subjected to statistical and SNK (Student-Newman-Keuls) analyses. Both procedures yielded numerical RDA values that permitted a ranking of the three test dentifrices. However, there was no direct correlation of the RDA values obtained by profilometry with those from the conventional radiotracer method. Significantly, one dentifrice rated as most abrasive using the radiotracer method was rated as moderately abrasive using profilometry. Additionally, there was loss of statistical significance and discrimination between products with RDA-PE. CONCLUSIONS: Given the lack of agreement between radiotracer and profilometry for the products tested in this study,it would appear that the RDA-PE method may not be equivalent to the traditional RDA radiotracer method, specifically in the higher abrasivity range.

Anti-hypersensitivity mechanism of action for a dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, 0.243% NaF and specially-designed silica.

PURPOSE: To evaluate the laboratory dentin occlusion efficacy and effects on dentin permeability of a new multi-benefit dentifrice in order to gain insight into the mechanism of action of a novel technology for dentin hypersensitivity relief based on a specially-designed silica and copolymer system. METHODS: Acid-etched human dentin was evaluated with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) after treatment with one of the following: (1) a dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, 0.243% sodium fluoride with specially designed silica (Test Dentifrice 1); (2) a dentifrice containing 0.3% triclosan and the same overall silica loading as Test Dentifrice 1 but without copolymer and the specially-designed silica (Placebo Dentifrice); (3) a commercially-available dentifrice containing 0.454% stannous fluoride in a silica base with sodium hexametaphosphate and zinc lactate (Test Dentifrice 2); and (4) a commercially-available non-sensitive dentifrice containing 0.243% sodium fluoride in a silica base (Negative Control Dentifrice). The composition of dentin treated with either Test Dentifrice 1 or Negative Control Dentifrice was analyzed using energy dispersive x-ray (EDX) and electron spectroscopy for chemical analysis (ESCA). To highlight dentin occluding efficacy of the specially-designed silica, dentin was treated with Test Dentifrice 1 formulated with fluorescently-tagged specially-designed silica and resulting occlusion followed with CLSM. The dentin occluding abilities of Test Dentifrices 1 and 2 were compared with the Negative Control dentifrice using CLSM after a 4-day cycling model consisting of twice daily dentifrice treatment and four acid challenges. Effects of treatment with Test Dentifrices 1 or 2 on dentin permeability and subsequent resistance of occluding deposits to acid dissolution and dislodgement by pulpal pressure were assessed using hydraulic conductance. RESULTS: Dentin specimens treated with Test Dentifrices 1 and 2 were significantly occluded compared to Placebo Dentifrice and Negative Control Dentifrice when visualized with CLSM. The level of occlusion remaining after challenge with cola was highest for dentin treated with Test Dentifrice 1 in CLSM xz views. Test Dentifrice 1 produced dentin surface deposits and tubule plugs containing silicon in addition to calcium and phosphorus as indicated by ESCA and EDX. CLSM visualization of fluorescently-tagged material confirmed occlusion by the specially-designed silica which was localized at the dentin tubule openings. Imaging of dentin by CLSM after the 4-day cycling model revealed a significantly higher amount of occluded tubules for dentin treated with Test Dentifrice 1 compared to the Negative Control Dentifrice or Test Dentifrice 2. Etched dentin treated with the Test Dentifrice 1 was significantly less permeable compared to that treated with the Negative Control Dentifrice, exhibiting over 80% reduction in dentin permeability. The occlusion provided by the Test Dentifrice 1 was maintained and provided significantly better reduction in permeability after extended pulpal pressure and acid challenge compared to dentin treated with Test Dentifrice 2.

The technology behind Colgate Simply White Toothpaste.

Colgate Simply White Toothpaste is a new advanced tooth whitening dentifrice that can be used every day. The synergy of abrasive stain removal with activated hydrogen peroxide delivers excellent performance in the removal of extrinsic and intrinsic tooth stain. Colgate Simply White Toothpaste provides other oral health benefits that have become the cost-of-entry into the toothpaste market: caries protection, tartar control, fresh breath, and a preferred flavor.