It’s no surprise that teeth whitening is the most popular esthetic dental treatment, with research showing that a whiter smile can improve patients’ oral health-related quality of life, self-image, and well-being. However, it can also be associated with some uncomfortable side effects. Here, we discuss the link between teeth whitening and dentin hypersensitivity, and how dental students can support their patients through the process.
How tooth whitening works
Dental stain (tooth discoloration) is classified as intrinsic or extrinsic in nature.
Intrinsic stains occur when chromophores (colored compounds) are present within the structure of the tooth, while extrinsic stains happen when chromophores are adsorbed onto the surface of the tooth, or incorporated into calculus, biofilm and/or pellicle present on the tooth surface. Extrinsic stain most often comes from strongly pigmented foods and drinks, e.g., red wine and coffee, or from smoking. There are two main types of tooth whitening.
While mechanical stain removal (such as a prophy) can address extrinsic discoloration, tooth whitening can target both extrinsic and intrinsic stains and is most commonly achieved using whitening gels, strips, trays or in-office treatments.
The most popular tooth whitening methods rely on hydrogen peroxide as the active ingredient, either delivered as hydrogen peroxide or as carbamide peroxide which breaks down to produce hydrogen peroxide through a chemical reaction. The hydrogen peroxide decomposes and the free radicals produced oxidize the double bonds of the chromophores. This breaks the bonds down into smaller, lighter-colored molecules. Light-activated systems are also used, while recent studies have found no difference in the whitening effect compared to use of whitening products that do not utilize light-activation.
Tooth whitening and sensitivity
Sensitivity is a common side effect associated with tooth whitening, with its occurrence and severity influenced by the concentration of the whitening agent and the duration for which it is applied.
As the free radicals produced by the hydrogen peroxide diffuse through the enamel and dentin, they can encourage movement of the fluid in the dentin tubules and stimulate nerve fibers at the pulp. This leads to the short, sharp pain characteristic of dentin hypersensitivity. The free radicals can also reach the pulp itself, triggering an inflammatory response that leads to reversible pulpitis.
Tooth sensitivity usually occurs at the time of treatment and is transient, resolving within several days. However, aggressive bleaching (such as bleaching too frequently) may result in an individual experiencing ongoing dentin hypersensitivity.
Preventing and treating hypersensitivity
Due to the risk of sensitivity and other side effects, the American Dental Association (ADA) Council on Scientific Affairs states that professional supervision of teeth whitening is important for achieving a successful and safe outcome. If your patient expresses an interest in tooth whitening, and prefers at-home whitening, always encourage them to do so in partnership with you.
Before conducting an in-office whitening treatment or recommending an at-home solution, be sure to conduct a thorough oral health and risk assessment. Patients can benefit from the pre-emptive use of a sensitivity toothpaste like Colgate Sensitive Toothpaste, which contains 5% potassium nitrate for relief of sensitivity. For those with existing dentin hypersensitivity, or restorations, you may wish to offer a prescription-strength toothpaste like Colgate PreviDent 5000 Sensitive Toothpaste, which contains 5% potassium nitrate along with with the added benefit of high-concentration fluoride for protection against dental caries.
To further reduce the risk of hypersensitivity for in-office bleaching procedures, choose a product like the Colgate Optic White System. Not only does this whitening system offer your patient an average seven-shade improvement, it’s also specially formulated and designed for no sensitivity.
For on-the-spot relief when they’re out and about, you can also recommend a topical serum like Colgate Sensitivity Relief Serum, which provides relief in 1 minute with a fingertip application.