JADA Continuing Education
Tooth whitening today
DAVID C. SARRETT, D.M.D., M.S.
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ABSTRACT
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Background. Methods to improve the esthetics of the dentition by tooth whitening are of interest to dentists, their patients and the public. In the past 20 years, research on bleaching and other methods of removing tooth discolorations has dramatically increased. Dentist-supervised and over-the-counter products now are available to solve a variety of tooth discoloration problems without restorative intervention. The indications for appropriate use of tooth-whitening methods and products are dependent on correct diagnosis of the discoloration.
Overview. Tooth-whitening methods include the use of peroxide bleaching agents to remove internal discolorations or abrasive products to remove external stains. Peroxide bleaching procedures are completed by the dentist in single or multiple appointments, or by the patient over a period of weeks to months using custom trays loaded with a bleaching agent. Both methods are safe and effective when supervised by the dentist. Microabrasion is indicated for the removal of isolated discolorations that often are associated with fluorosis. Whitening toothpastes remove surface stains only through the polishing effect of the abrasives they contain.
Conclusions and Practice Implications. Tooth whitening is a form of dental treatment and should be completed as part of a comprehensive treatment plan developed by a dentist after an oral examination. When used appropriately, tooth-whitening methods are safe and effective.
Since the introduction of the tooth-whitening technique that uses custom bleaching trays loaded with 10 percent carbamide peroxide gel 13 years ago,1 the demand for information on tooth bleaching and whitening has increased dramatically. When I conducted an online search of the National Library of Medicine’s MEDLINE database2 from 1969 to 1978 using the search terms "tooth AND (bleaching OR whitening)," I found 38 references. When I conducted similar searches for 1979 to 1988, 1989 to 1998, and 1999 to the present, I found 111, 456 and 225 references, respectively. Frazier and Haywood3 reported that 92 percent of dental schools now are teaching the custom tray bleaching technique. The safety and efficacy of this tooth-whitening method have been well-documented in clinical studies, and the ADA Seal of Acceptance has been awarded to tooth-whitening products.
Tooth whitening is, and should remain, dental care that must be professionally supervised.
If you visit the oral health care section of your pharmacy, you will become aware of the marketing of and assumed public demand for over-the-counter, or OTC, tooth-whitening products. This array of products includes toothpastes, mouthrinses and bleaching agents that make claims about their ability to whiten teeth. Dental professionals likely are able to evaluate the various claims made by these products. The average consumer, however, more likely will walk away confused or may purchase an ineffective product or a product that is not appropriate for and is potentially harmful to his or her tooth discoloration problem. The increased availability of these products indicates that they are being purchased and used by the public.
Patients need to decide between using OTC whitening products and seeking professionally supervised tooth-whitening treatment from dentists. A new option is to go to a tooth-whitening center at which tooth whitening is the primary service being delivered. Some patients may choose to continue receiving regular dental care from their general dentists, while using a tooth-whitening center for their dentist-supervised bleaching treatments.
The fact that patients may be receiving both OTC and dentist-supervised tooth-whitening treatments that are not part of a comprehensive oral health treatment plan raises concerns. Tooth whitening is, and should remain, dental care that must be professionally supervised. Tooth whitening should be part of a comprehensive treatment plan developed by a dentist after an oral examination.
In this article, I review the tooth-whitening options available to patients and discuss what is known about the safety and efficacy of tooth-whitening methods and products. The table
summarizes the indications for use and the adverse effects of tooth-whitening methods.
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TOOTH-BLEACHING OPTIONS
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Before the introduction of dentist-supervised home tooth whitening using custom trays and whiteners containing 10 percent carbamide peroxide agents, nonrestorative treatment of discolored teeth was performed using 35 percent hydrogen peroxide applied either internally or externally.4
Internal bleaching.
Internal application is limited to endodontically treated teeth. The so-called "walking bleach" involves sealing the bleaching agent inside the endodontic access cavity. The patient returns to the dentist to have the bleaching agent renewed until the desired shade change or maximum effect is achieved. Root resorption is a known potential adverse effect and can lead to the loss of the tooth.5
External bleaching.
Dentists perform external bleaching with 30 to 38 percent hydrogen peroxide by isolating gingival tissues and applying the bleaching gel to the tooth surface. This process may be used with or without heat or light during the bleaching treatment.4 The side effects for vital teeth include transient tooth sensitivity and gingival irritation. Both internal and external bleaching are effective in whitening discolored teeth and are indicated primarily for treatment of one or two teeth rather than entire arches.
Custom tray bleaching.
For patients seeking to whiten multiple teeth or entire arches, using a custom tray loaded with 10 percent carbamide peroxide gel generally is the method of choice. This treatment is most effective for whitening teeth with moderate yellow discoloration, moderate brown discoloration or both. Generally, a noticeable whitening effect will be achieved after a daily bleaching for two to six weeks, although the amount of color lightening may vary among people.6,7 The shade change appears to be stable for six to 12 months or longer for some patients,8 at which time patients may consider whether to bleach the teeth again for several days to regain the original effect. The research data on this treatment are quite extensive and indicate that this method is safe and effective when supervised by dentists.
The most common side effect of using a custom tray for bleaching is transient tooth sensitivity that can be managed by having the patient bleach on alternate days, reduce the bleaching time of each application or both.6,9 The sensitivity disappears once the bleaching is ceased. Although rare, patients who experience severe sensitivity that cannot be managed by altering the bleaching regimen should discontinue use of this tooth-whitening method. Gingival irritation also is reported by patients and most often is caused by an improperly fabricated tray.9 For patients seeking to whiten only one or two teeth, this method also is effective when the dentist modifies the tray and instructs the patient to only place bleach in the tray in the area of the teeth to be whitened.
Tetracycline staining has proven to be difficult or impossible to remove through traditional bleaching methods. A recent report10 indicates that using 10 percent carbamide peroxide in custom trays for three to six months can be effective in removing tetracycline staining. The adverse effects of long-term bleaching are not well-established; however, if the only alternative to bleaching is restoring the teeth with ceramic veneers or crowns, it seems reasonable to attempt bleaching first. The patient should be monitored closely, and only two to six weeks’ supply of bleach should be dispensed at one time.
Because there are many causes of tooth discoloration, a comprehensive oral examination by a dentist is required to ensure that patients are using the most effective tooth-whitening treatment.
OTC bleaching.
OTC products that use carbamide peroxide and prefabricated or user-modified trays are available,11 and some of these products appear to be equivalent in peroxide content to similar products sold only to dentists. Other OTC products deliver peroxide to the teeth using strips that patients apply to their teeth.12 There are very few published reports on the safety and efficacy of these products compared with the published research on dentist-dispensed whiteners containing 10 percent carbamide peroxide.
There are considerable concerns that the unsupervised use of these products can lead to adverse effects. Significant damage to enamel as the result of using OTC products has been reported.13,14 The long-term, repeated use of inappropriate products may lead to irreversible damage to tooth enamel. Patients who choose to bleach discolorations caused by undiagnosed caries and stained restorations can cause other problems. Since bleaching will not correct these discolorations, users of OTC bleaching products may overuse the products when trying to correct their discolorations. The consequences of undiagnosed caries are obvious.
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TOOTH SURFACE DISCOLORATION REMOVAL OPTIONS
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Toothpastes.
Toothpastes that make claims that they whiten teeth do so primarily by polishing away stains on the surface of the teeth. Some toothpastes also contain peroxide bleaching agents. There is no evidence that these tooth-pastes are effective in whitening teeth with internal discoloration. Toothpastes that have received the ADA Seal have been shown to be effective at removing stain through polishing while also reducing caries via fluoride.
The Centers for Disease Control and Prevention recently released its recommendations for using fluoride to control caries.15 It is evident that fluoridated water and tooth-paste are the fluoride delivery mechanisms that contribute the majority of caries-reduction benefits. The release of active fluoride during brushing is not a simple manner of having the toothpaste contain a fluoride ingredient, as other components such as the abrasive, flavorings and vehicle can render the fluoride ineffective.16,17 We must continue to encourage the public and patients to use fluoride-containing toothpastes that have been proven effective at reducing caries.
Microabrasion.
Isolated brown or white areas of enamel discoloration on otherwise normal teeth, which often are attributed to fluorosis, can be treated with microabrasion if the discoloration is less than a few tenths of a millimeter deep.18 Microabrasion is performed by applying an abrasive slurry of silicon carbide and hydrochloric acid using a manual or handpiece-driven rubbing action. This slow removal of enamel is easier to control than that performed using rotary instruments. The depth of the discoloration cannot be known until attempts are made to remove it. If the discoloration is too deep, it cannot be removed using microabrasion, and a restorative solution should be considered.
The mechanism of color improvement appears to be the removal of discolored surface enamel and the creation of a highly reflective enamel surface that may mask any remaining discoloration.19 The combined benefits of enamel microabrasion followed by home tooth whitening using carbamide peroxide have been reported in case studies.20–22 The combined regimen is reported to be most effective in patients who have prominent white areas on teeth that are yellowish or that have darkened with age. In vitro results support the application of neutral sodium fluoride after microabrasion is completed to create enamel that is significantly more resistant to demineralization than untreated enamel.23
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CONCLUSION
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There are many safe and effective tooth-whitening methods. For most patients, the methods described in this article should be used to correct discolored teeth before restorative intervention in undertaken. Because there are many causes of tooth discoloration, a comprehensive oral examination by a dentist is required to ensure that patients are using the most effective tooth-whitening treatment for their tooth discoloration problems.
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Dr. Sarrett is a professor and assistant dean, Academic Affairs, Virginia Commonwealth University School of Dentistry, and is a member, ADA Council on Scientific Affairs. Address reprint requests to Dr. Sarrett at P.O. Box 980566, Richmond, Va. 23298-0566, e-mail "dsarrett{at}ucu.edu".
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REFERENCES
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- Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int 1989;20:173–6.[Medline]
- National Library of Medicine. PubMed. Available at: "www.ncbi.nlm.nih.gov/entrez/query.fcgi". Accessed Sept. 30, 2002.
- Frazier KB, Haywood VB. Teaching nightguard bleaching and other tooth-whitening procedures in North American dental schools. J Dent Educ 2000;64(5):357–64.[Abstract]
- Goldstein RE. In-office bleaching: where we came from, where we are today. JADA 1997;128:11S–8S.[Abstract]
- Goon WW, Cohen S, Borer RF. External cervical root resorption following bleaching. J Endod 1986;12:414–8.[Medline]
- Haywood VB. Current status of nightguard vital bleaching. Compendium 2000;21(supplement 28):S10–S7.
- Matis BA, Mousa HN, Cochran MA, Eckert GJ. Clinical evaluation of bleaching agents of different concentrations. Quintessence Int 2000;31:303–10.[Medline]
- Leonard RH. Efficacy, longevity, side effects, and patient perceptions of nightguard vital bleaching. Compendium 1998;19:766–81.[Medline]
- Li Y. Tooth bleaching using peroxide-containing agents: current status of safety issues. Compendium 1998;19:783–96.[Medline]
- Leonard RH. Nightguard vital bleaching: dark stains and long-term results. Compendium 2000;21(supplement 28):S18–27.
- Li Y. Biological properties of peroxide-containing tooth whiteners. Food Chem Toxicol 1996;34:887–904.[Medline]
- Gerlach RW, Gibb RD, Sagel PA. A randomized clinical trial comparing a novel 5.3 percent hydrogen peroxide whitening strip to 10 percent, 15 percent, and 20 percent carbamide peroxide tray-based bleaching systems. Compendium 2000;21(supplement 29):S22–S8.
- Cubbon T, Ore D. Hard tissue and home tooth whiteners. CDS Rev 1991;84(5):32–5.[Medline]
- Hammel S. Do-it-yourself tooth whitening is risky. U.S. News and World Report. April 20, 1998:66.
- Center for Disease Control and Prevention. Recommendations for using fluoride to prevent and control dental caries in the United States. MMWR 2001;50:1–42.[Medline]
- Stookey GK. Are all fluoride dentifrices the same? In: Wei SH, ed. Clinical uses of fluorides. Philadelphia: Lea & Febiger; 1985.
- Hattab FN. The state of fluorides in toothpaste. J Dent 1989;17:47–54.[Medline]
- Croll TP. Enamel microabrasion: observations after 10 years. JADA 1997;128(supplement):45S–50S.[Abstract]
- Donly KJ, O’Neill MO, Croll TP. Enamel microabrasion: a microscopic evaluation of the "abrosion effect." Quintessence Int 1992;23:175–9.[Medline]
- Cvitko E, Swift EJ, Denehy GE. Improved esthetics with a combined bleaching technique: a case report. Quintessence Int 1992;23: 91–3.[Medline]
- Killian CM. Conservative color improvement for teeth with fluorosis-type stain. JADA 1993;124:72–4.[Abstract]
- Croll TP. Esthetic correction for teeth with fluorosis and fluorosis-like enamel dysmineralization. J Esthet Dent 1998;10:21–9.[Medline]
- Segura A, Dunly KJ, Wefel JS. The effects of microabrasion on demineralization inhibition of enamel surfaces. Quintessence Int 1997;28:463–6.[Medline]
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ABSTRACT
TOOTH-BLEACHING OPTIONS
