Pro-ArginTM Technology - Clinical Evidence for Instant and Lasting Relief of Dentin Hypersensitivity
D. Cummins, F. Ayad, N.Ayad, E. Delgado, Y.P. Zhang, W. DeVizio, L.R. Mateo, S. Nathoo, T. Schiff, R. Docimo, L. Montesani, P. Maturo, M. Costacurta, M. Bartolino, S. Dibart
The Efficacy of a New Dentifrice Containing 8.0% Arginine, Calcium Carbonate, and 1450 ppm Fluoride in Delivering Instant and Lasting Relief of Dentin Hypersensitivity
Colgate-Palmolive Technology Center
Piscataway, New Jersey, USA
Dentin hypersensitivity is an oral health problem that typically afflicts individuals in the age range of 20–49 years, especially 30–39 years.1,2 Numerous studies, which have included clinical evaluations by trained examiners through patient-based surveys, have reported prevalence figures in the range of 15-20%.3-6 However, higher levels, of up to 57% for individuals in general dental practice settings, and up to 98% in patients following periodontal therapy, have been reported.1,2,7-9 Dentin hypersensitivity is most commonly observed in the buccal-cervical regions of the canine and pre-molar teeth, sites which are also most susceptible to gingival recession.1,2
Dentin hypersensitivity is characterized by short, sharp pain arising from exposed dentin in response to stimuli that are typically thermal, evaporative, tactile, osmotic, or chemical in nature.1,10 Other defects or oral disease conditions, such as cracked teeth and dental caries, can give rise to dental pain, therefore treatment decisions rely upon differential diagnosis to correctly attribute dental pain to dentin hypersensitivity.1,2,11
The hydrodynamic theory suggests that dentin hypersensitivity occurswhen an external stimulus, such as cold air, induces a change in fluid flow within the dentin tubules. This, in turn, results in a pressure change across the dentin which activates the nerve response, causing a painful sensation.1,8,12 For the hydrodynamic mechanism to induce pain, the dentin tubules must become exposed, be open at the exposed surface, and patent at the pulp.1,7 Ex vivo studies have shown that sensitivity is strongly correlated with the number and diameter of exposed and open dentin tubules.1,13,14
Clinical evidence supports a conclusion that gingival recession is the primary cause of dentin exposure and, as a result, is a major predisposing factor for dentin hypersensitivity.1 Gingival recession primarily occurs through the mechanical forces encountered during overzealous tooth brushing, or through the biological processes involved in periodontal tissue breakdown.1,9 Once gingival recession occurs, the cementum can thereafter erode away, exposing the underlying dentin. Likewise, current evidence suggests that acid erosion is an important factor in opening up exposed dentin tubules, and mechanical forces may have an exacerbating effect.1,8
Advances in scientific understanding have laid the foundation for approaches to the management of dentin hypersensitivity that encompass the control of etiological and predisposing factors, as well as treatment of the pain itself.1 Products to alleviate dentin hypersensitivity have followed one of two treatment approaches: 1) to interrupt the neural response to pain-triggering stimuli; or 2) to occlude open dentin tubules to block the hydrodynamic mechanism. In order to apply appropriate treatment modalities, a differential diagnosis must first exclude other conditions that can cause pain, and then treat the dentin hypersensitivity.
To successfully treat the condition requires that etiological and predisposing factors be identified and then minimized through professional dietary advice and oral hygiene instruction. The next step in treatment is the assessment of individual needs.1 Typically, the first treatment option is to recommend use of a desensitizing toothpaste. For many individuals, this will result in an improvement if used regularly for several weeks. Home-use prescription fluoride products may offer additional benefits, and so may be useful to those who do not experience sufficient relief from a desensitizing toothpaste. Finally, a professionally applied in-office product, which can occlude the open dentin tubules and block the hydrodynamic mechanism, may be appropriate for severe sufferers with additional treatment needs.10
Most desensitizing toothpastes are based upon the first approach, and contain a potassium salt to increase the nerve depolarization threshold, and thus modulate or suppress the sensation of pain.15,16 Potassium nitrate (5%), potassium chloride (3.75%), and potassium citrate (5.5%) are used interchangeably, as each provides 2%potassium ion which is the active ingredient. Clinical studies have shown that toothpastes containing each of these ingredients are effective in reducing dentin hypersensitivity. 17-32 Although some studies have failed to show benefits as compared to a placebo control product,33-35many have shown significant reductions in sensitivity, over four to eight weeks of twice-daily use, as compared to control products.17-32 A recent review has summarized these clinical data.36
The second approach, to occlude open dentin tubules, has been broadly applied to professional in-office products.37 Published data show that products such as Gluma® (Heraeus Kulzer, South Bend, IN, USA) and Duraphat® (Colgate-Palmolive Company, New York, NY, USA) are clinically proven to provide sensitivity relief after one ormore applications,38-42 whereas other products appear not to have been clinically evaluated. In contrast, there has been only limited application of the approach of occluding dentin tubules in desensitizing toothpastes. Strontium chloride-based toothpastes were available prior to the development of potassium-based products, and have been largely superseded by them. Toothpastes containing stannous fluoride have been shown to be effective in reducing sensitivity over four to eight weeks of twice-daily use.43-46 However, stannous fluoride has not found widespread application, largely because of its well-documented negatives, i.e., tooth staining and poor taste.36
Both strontium and stannous are believed to work by precipitating insoluble metal compounds on dentin surfaces to occlude, or partially occlude, open dentin tubules.36 In a review published in 2007, Markowitz and Pashley suggested that new technologies should target the underlying causes, as well as the symptoms of dentin hypersensitivity. Specifically, they proposed that increasing the surfacemineral density of exposed dentin,while plugging and sealing open tubuleswith a calcium-rich dentin-like material, could increase its resistance to wear and erosive attack by blocking diffusion through open tubules into the dentin sub-surface. Further, they suggested that the ideal dentin hypersensitivity treatment would accelerate and enhance nature’s own desensitizing process of occlusion of open dentin tubules.47 This has now been accomplished with the development and validation of a novel technology based upon 8.0% arginine and calcium carbonate.