Bright, White, and Sensitive: An Overview of Tooth Whitening and Dentin Hypersensitivity

Cosmetic whitening treatments are here to stay, with more than 29% of American adults requesting the procedures from their dentists to achieve or maintain a whiter smile (Table). According to the American Academy of Cosmetic Dentistry, in the past 5 years some dentists have reported as much as 40% growth in aesthetic services. Of these, whitening procedures are the most requested.1 With the increasing number of whitening patients, it is not surprising that one out of 5 adults suffers from dentin hypersensitivity.2 In fact, 55% to 75% of patients undergoing bleaching procedures report sensitivity, and 41% of dentists recommend patients discontinue whitening to relieve the painful symptoms.3
Notably, of the 22% of US adults suffering from dentin hypersensitivity, three quarters of them report they are somewhat and/or extremely bothered by the pain.2 What many oral healthcare providers may not know, however, is that 70% of sensitivity sufferers are less than 50 years old.2 Among this group, whitening is not single-handedly to blame; diet choices and other lifestyle factors are often significant contributors. Educating patients about sensitivity symptoms, triggers, and ways to manage the condition can help ensure a successful, pain-free whitening experience that doesn’t have to end before desired results are achieved.

THE FACTS ABOUT SENSITIVITY

While sensitivity can occur due to a variety of factors, a majority of patients undergoing whitening treatments will experience bleaching-related sensitivity. As previously noted, dentin hypersensitivity affects a significant number of patients due to tactile causes as well. It occurs when tubules at the exposed dentin surface are exposed to a stimulus or trigger, leading to sharp pain.4 As such, patients often subconsciously avoid the triggers that inflict this pain. Without realizing it, they may modify their behaviors to prevent contact with extreme temperatures (ie, hot or cold air or beverages), acidic food and beverages (ie, oranges, lemonade, or soft drinks), and sweet, sugary foods and beverages.
Often patients will not schedule an appointment to address their sensitivity, and they are unlikely to bring it up in conversation without prompting. This makes any discussion about dentin hypersensitivity one that dental professionals must initiate. While all patients should be questioned about sensitivity, the majority of sufferers are between the ages of 20 and 50 years old, with a peak in patients 30 to 40 years of age.5 Of that group, females are significantly more likely to experience sensitivity than males.5 When you also consider that 96% of patients requesting in-office cosmetic services are female, it becomes obvious that addressing sensitivity with this patient demographic is particularly important.

THE HYDRODYNAMIC THEORY

Figure. The Hydrodynamic Theory illustrated: Fluid within the dentinal tubules can flow in either an inward or outward direction depending on pressure differences in the surrounding tissue. A stimulus that makes contact with a tooth surface with open tubules causes a fluid disturbance, or change in flow direction, which the patient perceives as pain.

When patients inquire about sensitivity and why it occurs, the hydrodynamic theory can help practitioners illustrate the where, why, and how. According to the hydrodynamic theory, when a stimulus is applied to a tooth surface having open or patent dentinal tubules, the fluid inside the tubules moves.6 When this change in fluid flow occurs, it creates a painful response (Figure). Additionally, the hydrodynamic theory demonstrates that hypersensitivity can be controlled by penetrating the dentinal tubules and depolarizing the nerve. Historically, this has been effectively accomplished with a dentifrice containing potassium nitrate.

DIAGNOSIS AND MANAGEMENT

Once it has been determined that a patient is experiencing sensitivity, dental professionals should collect a complete history of the condition, including the following information:7

  • History and nature of pain
  • Location of sensitivity pain and identification of affected teeth
  • Pain consistency (ie, are the same teeth consistently involved, or are differing areas involved in various circumstances?)
  • Pain intensity
  • Triggers that initiate sensitivity (Hot or cold air, hot or cold beverages, etc)
  • Frequency and duration of pain.
Table. Tooth-whitening options.9
In-office

• Hydrogen peroxide

Approximately 25% to 35%

• Requires soft-tissue protection
• Activator

Chemical
Heat
Light

• Most rapid results
• Dentist applied

Take-home

• Carbamide peroxide

Up to 21%

• Used in trays

Twice a day
Overnight

• Patient applied

Over-the-counter

• Hydrogen or carbamide peroxide
• Available as:

Tray systems
Strips
Paint-on liquids
Rinses

• Consumer applied

Collecting this information from the patient at the initial report of sensitivity will allow you to track the condition’s severity over time. If the sensitivity pain increases or is unable to be resolved, further investigation may be necessary to rule out an underlying problem such as a split or cracked tooth hidden by an amalgam restoration. To help ease initial sensitivity pain temporarily, you can suggest that the patient take ibuprofen (as directed) until he or she is able to visit your office.
Patients may avoid addressing sensitivity pain because they presume treatment is painful, costly, and/or time-consuming. However, simple and effective home treatments may resolve the painful twinges by depolarizing exposed nerve endings. For example, a recent clinical study found that patients who brushed with a dentifrice containing 5% potassium nitrate, such as Sensodyne Fresh Mint (Glaxo-SmithKline), 2 weeks prior to as well as during and after whitening treatment were less likely to experience sensitivity.8 The use of a potassium nitrate dentifrice such as Sensodyne can help patients manage the sensitive side effects of bleaching without interfering with the whitening process itself, thus helping to ensure that patients will achieve their desired whitening results.

Conclusion

Not surprisingly, 43% of adults report they are unhappy with the current state of their teeth, as evidenced by the growing percentage of requests for cosmetic treatments such as whitening.8 However, with your help, patients requesting cosmetic treatments can achieve the bright, white smile they desire without the painful symptoms of dentin hypersensitivity. Instead of discontinuing treatment, oral healthcare providers should consider a patient’s cosmetic procedures, diet, and life-style. They can then recommend an easy and affordable solution to manage sensitivity pain, ultimately ensuring that their patients ideal smile is achieved.


References

  1. North American Survey: The State of Cosmetic Dentistry. A Levin Group Study Commissioned by the American Academy of Cosmetic Dentistry. AACD Web site. http://www.aacd.com/press/releases/2004%20National%20Survey.pdf. Published 2004. Accessed March 25, 2008.
  2. Data on file, GlaxoSmithKline.
  3. Haywood, VB. Treating sensitivity during tooth whitening. Compendium of Continuing Education. 2005;26(9), Suppl 3:11-20.
  4. Gillam DG, Aris A, Bulman JS, et al. Dentine hypersensitivity in subjects recruited for clinical trials: clinical evaluation, prevalence and intra-oral distribution [published correction appears in J Oral Rehabil. 2003;30:446]. J Oral Rehabil. 2002;29:226-231.
  5. Addy M. Dentine hypersensitivity: new perspectives on an old problem. Int Dent J. 2002;52:367-375.
  6. Drisko CH. Dentine hypersensitivity: dental hy-giene and periodontal considerations. Int Dent J. 2002;52:385-393.
  7. Haywood VB. Dentine hypersensitivity: bleaching and restorative considerations for successful management. Int Dent J. 2002;52:376-384.
  8. Data on file, GlaxoSmithKline.
  9. Margeas RC. New advances in tooth whitening and dental cleaning technology. The Academy of Dental Therapeutics and Stomatology Dental Continuing Education Web site. http://www.ineedce.com/toothwhit.html. Accessed March 25, 2008.

Dr. Marvin is a graduate of the University of Minnesota School of Dentistry. She practices family dentistry in Stillwater, Minn, and can be reached at klmarvin@hotmail.com.



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