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Inside Dentistry

October 2007, Volume 3, Issue 9
Published by AEGIS Communications


Getting the Benefit Without the Side Effect: Whitening and Sensitivity

Wyn Steckbauer

The pursuit of a bright, white smile has long been an interest of dental patients. In recent years, however, that pursuit has translated into significant business. Today, tooth-whitening products generate more than $1 billion in over-the-counter (OTC) sales alone, and that number is expected to climb.1 The American Academy of Cosmetic Dentistry says that whitening is now the most commonly requested dental procedure.2

Despite the surge in demand, a common whitening side effect continues to concern patients and clinicians: dentin hypersensitivity. While dentin hypersensitivity affects approximately 22% of American adults according to a recent survey,3 55% to 75% of whitening patients report suffering some degree of whitening-related sensitivity.4 Research has also suggested that as many as 41% of dentists recommend discontinuation of whitening treatments to address sensitivity.

With dentin hypersensitivity a significant problem, whitening-related sensitivity presents an opportunity to help large numbers of patients ease discomfort while encouraging them to adhere to cosmetic treatments that lead to a satisfactory result.

AVAILABLE WHITENING PRODUCTS
Today’s whitening products, whether dispensed by dentists or available OTC, generally rely on peroxide (either carbamide or hydrogen peroxide) to whiten enamel.5 Peroxide has been known to perform this function since the 1970s.6

In a statement addressing the safety and effectiveness of whitening products, the American Dental Association (ADA) categorizes them as "peroxide-containing whiteners or bleaching agents" and "whitening toothpastes (dentifrices)." Home-use products bearing the ADA Seal of Acceptance contain 10% carbamide peroxide, while professionally applied whitening products contain hydrogen peroxide in concentrations of 15% to 35%.7

Research has shown that whitening products using peroxide as the main bleaching agent are likely to cause at least some degree of tooth sensitivity and gingival irritation.8 This occurs because the chemical byproducts of peroxide pass through the enamel and into the pulp.5 There also are correlations between the frequency of applications and increased sensitivity, as well as concentrations of the bleaching agent.8

Broadly, dentin hypersensitivity is defined as a short, sharp pain arising from exposed dentin in response to stimuli that is not due to any other form of defect or pathology.5 The hydrodynamic theory attributes the cause of the dentin hypersensitivity to fluid movement around dental tubules that cause pressure changes on nerve endings within the pulp and a subsequent feeling of pain.5

COMMONLYREPORTED TRIGGERS

In addition to whitening treatments, common triggers3 of dentin hypersensitivity include:

  • cold stimulus (water, ice);
  • hot stimulus (coffee, tea);
  • air (hot or cold);
  • sweet (candy, sugars);
  • sour (lemonade);
  • touch (brushing or flossing); and
  • acidic foods/beverages (wine).

DIAGNOSIS AND TREATMENTS

Despite the widespread occurrence of dentin hypersensitivity, research has indicated that patients often avoid mentioning sensitivity because they are not aware that effective treatments exist.9 The implication of this fact for clinicians is that a proactive approach is typically required to identify the incidence and recommend treatment. Simply initiating a conversation about lifestyle choices and/or cosmetic goals with your patients can help create an easy transition to discussing sensitivity.

Productive questions to ask during office visits can include:

  • Have you recently undergone whitening or bleaching treatment?
  • If so, did you discontinue or interrupt treatment because of tooth sensitivity?
  • Are you considering using whitening or bleaching treatments in the future?

An answer of "yes" to any of these questions presents an opportunity for the provider to recommend a remedial course of action. There are two essential categories of treatment available to patients, both of them involving desensitizing agents containing fluoride or potassium nitrate.

In-office treatments include the use of bleaching trays to apply fluoride or potassium nitrate to the teeth, which provides some control while not inhibiting the bleaching process.8 These provide immediate relief, but do not provide a lasting benefit of more than a few weeks. When the substances wear away, the sensitivity returns.

More sustained relief can often be realized with the use of an OTC dentifrice containing 5% potassium nitrate (such as Sensodyne®, GlaxoSmithKline, Research Triangle Park, NC), which depolarizes nerve endings within the tubules. A recent study concluded that dentifrices containing potassium nitrate and fluoride used before and during a bleaching regimen can be a useful adjunct for managing sensitivity caused by whitening products, increasing patient satisfaction with whitening experiences, and increasing patient willingness to repeat the bleaching treatment.8 The initiation of such a dentifrice can be a good first step as a 4-week to 6-week trial before consideration of in-office treatments or take-home bleaching procedures, as well as a useful addition to treatment already in progress.

Certain perceptions persist with regard to desensitizing toothpastes, which may contribute to providers’ reluctance to recommend and patients’ reluctance to try them. For example, patients may consider desensitizing toothpastes fit for short-term use only, while many such products are safe for everyday, long-term use. Patients typically see noticeable results after 2 weeks of twice-daily use and can gain continued relief with sustained use. Patients also may associate anti-sensitivity toothpastes with an objectionable flavor or providing a poor feel to their mouth, whereas products on today’s market demonstrate significant advancement in these areas. Potassium nitrate, the active ingredient in many of today’s products, does not have the unpleasant taste of the strontium chloride-based formulations of the past.

CONCLUSION

With the popularity of whitening treatments on the rise, the already-high incidence of dentin hypersensitivity is likely to increase quickly as well. It is not often that a widespread problem can be addressed by a relatively modest amount of patient education and readily available OTC products, but dentin hypersensitivity appears to present such an opportunity. It is an opportunity to increase patients’ satisfaction with their treatments and to ease common discomfort—all at the small cost of asking some questions and making some simple, low-cost, and low-involvement recommendations that will help them significantly manage pain.

REFERENCES
1. Marr M. What’s the best way to a high-wattage grin? The Record. McClatchy Newspapers. 2007. Available at: www.northjersey.com. Accessed July 31, 2007.

2. American Academy of Cosmetic Dentistry. Cosmetic Dentistry Booms as Beautiful Smiles Make Summer Sizzle. American Academy of Cosmetic Dentistry Web site. Available at: www.aacd.com/press/releases/2005_06_16.asp. Accessed July 31, 2007.

3. Gillam DG, Aris A, Bulman JS, et al. Dentine hypersensitivity in subjects recruited for clinical trials: clinical evaluation, prevalence and intra-oral distribution. J Oral Rehabil. 2002:29(3):226-231.

4. Haywood VB. Current status and recommendations for dentist-prescribed, at-home tooth whitening. Contemporary Esthetics and Restorative Practice. 1993;3(suppl): 2-11.

5. Using Sensodyne® to Alleviate Dentin Hypersensitivity. Inside Dentistry. 2007;3(5): 108.

6. Yarnell A. Teeth whiteners. Chemical and Engineering News. 2003;81(6): 29.

7. American Dental Association. ADA Statement on the Safety and Effectiveness of Tooth Whitening Products. American Dental Asso-ciation Web site. Available at: http://www.ada.org/prof/resources/positions/statements/whiten2.asp. Accessed July 31, 2007.

8. Haywood VB, Cordero R, Wright K, et al. Brushing with a potassium nitrate dentifrice to reduce bleaching sensitivity. J Clin Dent. 2005;16(1):17-22.

9. Kielbassa A. Dentine hypersensitivity: Simple steps for everyday diagnosis and management. International Journal of Dentistry. 2002:52(5):394-396.

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About the Author
Wyn Steckbauer, DDS
Private Practice
Oshkosh, Wisconsin

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