Intraoral evaluation of mineralization of cosmetic defects by a toothpaste containing calcium, fluoride, and sodium bicarbonate.
Howard E. Strassler, DMD
Litkowski LJ, Quinlan KB, Ross DR, et al. Compend Contin Educ Dent. 2004;25(9 Suppl 1):25-31.
New dual-phase fluoride toothpastes that contain soluble calcium, phosphate, and baking soda have recently been introduced into the market. These toothpastes are designed to fill in small surface defects in tooth enamel and thereby enhance tooth esthetics such as gloss. This two-part study was designed to assess these superficial mineralizing effects from using one of these products compared to an experimental calcium-containing, bicarbonate-free formulation and a conventional fluoride toothpaste using an intraoral model. Enamel specimens with four types of defects were mounted into an intraoral appliance and placed in the mouths of volunteers for 1 month. The four types of defects were whitening toothpaste abrasion, coarse abrasion, natural dimpling, and acid-etching. Before and after intraoral exposure, scanning electron microscope photographs of the specimens were made. The surface microhardness of the acid-etched specimens also was determined. The volunteers brushed their specimens twice daily with one of the three randomly assigned toothpastes. The toothpastes were a two-phase, calcium-containing, bicarbonate-based toothpaste (now as Arm and Hammer Age Defying toothpaste, Church and Dwight); an experimental, two-phase, calcium-containing, bicarbonate-free toothpaste; and a conventional toothpaste. Only the calcium-containing toothpastes showed unequivocal signs of mineral deposition into surface defects, leading to smoothing of the enamel. All three products significantly increased the hardness of the etched enamel, presumably because of fluoride. However, only the two calcium-containing toothpastes gave significantly greater hardness increases than the conventional toothpaste; the specimens treated with a conventional toothpaste were indistinguishable from those treated with saliva.
Recently, there has been excitement in the tooth remineralization research community as a result of the use of and effectiveness of soluble amorphous calcium phosphate (ACP) in remineralizing enamel when used as an additive to chewing gums, mints, toothpastes, and brush-on pastes. This calcium phosphate chemistry has been shown to remineralize acid-attacked and eroded enamel. Unlike fluoride alone, which becomes incorporated into the superficial surface of enamel and dentin without itself adding new mineral or changing the surface structures’ physical appearance, under the influence of fluoride ACP actually reverses the erosive effects of acid attack on enamel by replacing lost mineral.
These two studies used a variety of different qualitative methodologies to demonstrate the remineralization of enamel with the use of an ACP, bicarbonate-containing, fluoride toothpaste (Arm and Hammer® Age Defying toothpaste, Church and Dwight, Princeton, NJ). There was definitive proof of reversal of the acid demineralization with the use of a thorough assessment of surface roughness, gloss, and microhardness by remineralization through calcium phosphate deposition. This research parallels an important clinical study which compared a conventional fluoride toothpaste to an ACP-containing fluoride toothpaste for the prevention of caries in a radiation therapy population.1 There is no doubt that this population is at highest risk of caries because of changes in the saliva-protective ability and a decrease in salivary flow. Radiation caries is insidious and very difficult to control. What this study demonstrated was that the remineralizing ability of a fluoride toothpaste containing ACP was significantly superior to the conventional fluoride toothpaste in preventing root caries in this at-highest-caries-risk population.
Dental professionals recommend fluoride-containing oral care products to all patients. Now, for those patients at highest risk (eg, patients with orthodontic brackets, patients with recession and at risk for root caries, patients with bulimia, gastroesophageal reflux disease, or those who ingest high quantities of acid-containing and enamel-eroding beverages and foods), we can recommend products delivering calcium and phosphate ions for routine use to prevent caries and remineralize and resurface existing acid-demineralized enamel.
References1. Papas A, Russell D, Singh M, et al. Double blind clinical trial of a remineralizing dentifrice in the prevention of caries in a radiation therapy population. Gerodontology. 1999;16(1):2-10.
|ABOUT THE AUTHOR|
|Howard E. Strassler, DMD |
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School, Baltimore,Maryland