At-Home Vital Tooth Bleaching
A current status update on professionally dispensed and OTC methods.
By Howard E. Strassler, DMD
Tooth whitening refers to a general category of products that have the potential to change the shade of teeth. With the increased knowledge and interest patients have in changing the appearance of their smile through esthetic dentistry, the conservative technique of tooth whitening with vital bleaching has gained wider acceptance. Also, there has been an increase in the number of over-the-counter (OTC) products that provide tooth whitening either by using chemical mechanisms similar to professionally dispensed bleaching or by reducing surface stains on teeth as a cost alternative to in-office dental fees for whitening.
Professionally dispensed vital tooth bleaching refers to the materials, techniques, and devices used for vital bleaching that are dispensed in the dental office. In recent years patients have shown an increased interest in the use of bleaching for treatment of discolored teeth. Bleaching, especially at-home bleaching, has been of interest to dentists and patients alike because it is the most conservative, non-invasive treatment modality currently available to the dental clinician to change the appearance of teeth. Bleaching is usually used to lighten the shade of teeth that are darkened due to intrinsic and extrinsic discolorations. Techniques can include a range of concentrations of hydrogen and carbamide peroxide, in-office methods with and without light or heat enhancement, professionally dispensed whitening strips, and tray bleaching.
This article will review the current status of at-home tooth bleaching with professionally dispensed and OTC products and some of the reported adverse effects.
The acceptance of tooth bleaching as a non-invasive, conservative treatment for discolored teeth has gained increased acceptance over the past 40 years. The earliest methods of teeth bleaching used special heat lamps, dental dam application, high concentrations of hydrogen peroxide (30%), and multiple office visits.1 Reports of extended tooth sensitivity and chemical burns to the gingival tissues led to a desire for easier, less at-risk methods of whitening teeth.
One of the early reports of the concept of professional tray vital bleaching started with well-fitted, custom-made trays from patient impressions and casts as vehicles to hold a 10% carbamide peroxide gel.2 Today the clinician has many choices for providing patients with at-home tooth bleaching materials and techniques, including a variety of different types of tray and trayless systems that provide for the delivery of either hydrogen or carbamide peroxide in a wide range of concentrations. When comparing the chemical concentration of hydrogen peroxide to carbamide peroxide, the following formula ratio should be used: 3% hydrogen peroxide is equivalent to approximately 10% carbamide peroxide. The current generation of bleaching peroxides have improved shelf lives: 1 to 2 years for carbamide peroxide and 1 to 2 months for hydrogen peroxide.3 There have also been modifications in the chemistry of carbamide peroxides to allow their bleaching potential to last longer for overnight tray bleaching.4 Hydrogen peroxide bleaching products are recommended for 30-minute wear in a tray because they have a chemical degradation of more than 50% of their bleaching potential within 30 minutes. When selecting vital bleaching systems, the clinician should understand which active ingredient is present—carbamide or hydrogen peroxide—so that recommendations for tray use will be appropriate for the type of peroxide being dispensed. Some manufacturers offer both carbamide and hydrogen peroxide bleaching systems (eg, DayWhite® ACP and NiteWhite® ACP, Discus Dental, www.discusdental.com/nitewhite-daywhite.php) that feature different concentrations of both hydrogen peroxide and carbamide peroxide within each name brand. In these instances, the staff and clinician need to be familiar with the specific recommendations of the product they are dispensing.
Tooth whitening with vital bleaching is relatively long lasting. In the case of a patient with mild to moderate fluorosis staining, microabrasion combined with tray bleaching may provide the whitening effect the patient desires. Microabrasion is a technique to remove superficial enamel discoloration by rubbing a high-concentration hydrochloric acid-abrasive paste on the discolored enamel surface (Figure 1, Figure 2, Figure 3 and Figure 4). While bleaching relapse has been reported,5-7 bleaching can be maintained through the use of whitening and bleaching toothpastes with yearly touch-up bleaching using a peroxide bleaching agent in the patient’s custom-fitted tray. If the patient has misplaced their bleaching trays, touch-ups can also be accomplished by recommending that a patient use OTC whitening strips or disposable bleaching trays to avoid remaking the bleaching tray.
When professional vital tooth bleaching using trays for at-home use was first introduced, there were concerns over adverse reactions and patient complaints. These included unacceptable taste of bleaching gel, gingival irritation, uneven appearance of the teeth during the initial stages of bleaching, and tooth hypersensitivity while bleaching. Clinician and patient complaints concerning issues of taste have been addressed with an expanded selection of better flavors for improved patient acceptance. Gingival irritation has been seen with trays that were poorly fabricated due either to inaccuracy of the casts or to the need for scalloping the tray for higher concentrations of hydrogen and carbamide peroxide bleaching gels.8 This can be avoided with more attention to detail when the dentist or chairside assistant is making impressions and casts for tray fabrication. During the initial bleaching, especially with higher concentrations of tray bleaching gels, patients have reported an uneven appearance of the teeth during the first week.8 This uneven coloration disappears after the first week of bleaching.
Tooth sensitivity during bleaching has been the most common adverse reaction. In clinical research studies, tooth sensitivity during bleaching, either with at-home tray delivery or in-office procedures, has been reported in a range of 18% to 78% of patients.9-11 The sensitivity due to tooth bleaching in clinical observations suggests that it is transient with no long-term effects.12 To minimize tooth sensitivity during vital tooth bleaching, the clinician can use a peroxide with desensitizing agent added, and can recommend that the patient decrease the time the tray is worn the first week to no more than 1 hour a day for carbamide peroxide products or as little as 15 minutes a day for higher-concentration hydrogen peroxides. Also, a patient can use an OTC 5% potassium nitrate desensitizing toothpaste before starting and during bleaching treatment.9,13
Recommendations for Successful At-Home Tray Bleaching
Higher concentrations of carbamide peroxide and hydrogen bleach worn in a tray show faster initial whitening, but when comparing 10% carbamide peroxide to higher concentrations over a 6-week period there is no difference in the final result.14,15 For many patients, even though manufacturers provide a 2-week regimen for bleaching, 4 weeks of bleaching brings the patient to a “whiter” endpoint.15 Providing the maxillary tray first for 2 weeks of bleaching allows the patient to realize the shade change when compared to the mandibular teeth. Bleaching both arches simultaneously does not allow the patient to fully appreciate the whitening effect.
Bleaching for patients with intrinsic dentin staining due to tetracycline can have success with vital bleaching. In cases where the patient has moderate and dark tetracycline staining, bleaching over an extended time of 3 to 6 months provides for noticeable tooth whitening, but the cervical areas where thinner enamel is present will still have a darkened appearance due to discolored dentin shine-through.16,17
Trayless Bleaching: Professionally Dispensed and OTC
Patients are using OTC whitening products in greater numbers. One problem with these products, especially OTC bleaching products, is that patients are using them without being diagnosed for the esthetic condition for which they are bleaching. An in-office dental examination for a patient-perceived esthetic condition provides for a comprehensive evaluation and diagnosis of intraoral conditions. Use of OTC bleaching and whitening products may be inappropriate for that patient’s condition. Also, a patient using an OTC containing a peroxide bleaching product may experience detrimental effects related to the use of bonding agents in the placement of composite resin restorations.18-20 In this author’s experience, for patients using OTC bleaching products, their teeth will look unusually lighter in color or opalescence in appearance. As a clinician, it is worthwhile to ask the patient if they have bleached their teeth and, if so, how recently. It is recommended that the clinician, including orthodontists placing bonded brackets, wait at least 2 weeks post-bleaching before doing an adhesive procedure.21
In recent years, manufacturers have developed novel, trayless methods of bleaching teeth. Crest Whitestrips® (Procter and Gamble, www.whitestrips.com) was the first product introduced for professional in-office dispensing. Within a year after this, a lower hydrogen peroxide concentration was released as an OTC product. In the past 2 years, the concentration of the hydrogen peroxide in both professionally dispensed and OTC Whitestrips® has been increased, and patients have more choices and options with other OTC bleaching strip systems that have become available from other manufacturers. These whitening strips have been shown to be effective at tooth whitening similar to the use of at-home carbamide peroxide bleaching products with trays.22-24 Also, as teenagers purchase and use whitening strips that contain hydrogen peroxide, safety and effectiveness concerns may arise over adolescents using these products. However, according to a recent research report evaluating whitening strips used by teenagers, there was significant tooth whitening with no adverse effects.25
A limitation of many of the bleaching strip systems is the number of teeth that can be whitened. OTC strips only cover the anterior teeth from canine to canine, are difficult to apply, and many times do not contact facial surfaces when a patient has misaligned teeth. If a patient asks a clinician about the use of whitening strips, it is important to evaluate the alignment of the teeth to verify that the tooth position will be compatible with the use of strip whitening. A recently introduced in-office dispensed thin bleaching film (20% carbamide peroxide whitening) (SheerWhite™, CAO Group, www.caogroup.com) is easily moldable to the teeth—even slightly misaligned teeth—stays in place, and provides coverage almost to the first molars (Figure 5). In an effort to eliminate impressions, casts, and custom bleaching trays, disposable tray-like systems have been introduced that provide extended coverage to an entire dental arch and are not dependent on tooth alignment. These novel, single-use trays that are professionally dispensed provide for patient comfort and ease of use, utilizing a variety of tray sizes with a thin bleaching membrane system (Opalescence® Tréswhite Supreme, Ultradent Products, www.ultradent.com). This single-use tray system contains a 10% or 15% hydrogen peroxide with a 5% potassium nitrate and fluoride for desensitizing. The bleaching agent is contained within the tray using a gel-like barrier at the gingival margin that ensures improved comfort when worn. The author has had a number of dental students try this system and they have reported favorably on the ease of use with good whitening results. Benefits of this disposable tray system are that it only needs to be worn 30 minutes twice a day; it requires no filling of a tray before insertion, eliminating the chance of the patient putting too much or too little product in; and it eliminates the need for patient impressions, casts, and tray fabrication. An OTC single-use disposable tray for bleaching with hydrogen peroxide has also been introduced (Aquafresh® White Trays®, GlaxoSmithKline; www.aquafresh.com).
Patient Selection for Vital Tooth Bleaching
It is important to select patients whose conditions offer the best prognosis for success with bleaching. Key factors affecting the final result after bleaching include concentration of the bleaching agent, duration of use of the bleaching agent, type of tooth discoloration, teeth color, and patient’s age.26 It has been reported that tooth discolorations with the best prognosis for whitening are:
• yellowing of the teeth without any systemic or developmental cause (eg, food, smoking, aging, staining).
• mild fluorosis staining.
• mild tooth darkening due to trauma.
• mild tetracycline staining.27,28
There have been case reports and research that have demonstrated moderate to severe tetracycline discoloration can be lightened in shade with overnight use of a vital mouthguard bleaching over a period of 3 to 6 months.16,17
Clinicians have many choices for clinically successful at-home bleaching for their patients, including the type of bleaching agent, carbamide peroxide and hydrogen peroxide in various concentrations, and formulations with and without desensitizing agents. Also, recommendations for at-home vital bleaching should be personalized for the patient’s tooth discoloration condition.
Vital tooth bleaching is an effective treatment modality that can significantly change the appearance of teeth and provide a high level of patient satisfaction. Consideration should be given to the fact that there are additional clinically acceptable choices for tooth whitening using in-office bleaching and OTC whitening products. Tooth bleaching, with its conservative nature and little, if any, risk, make it an important part of an esthetic dentistry treatment plan.
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About the Author
Howard E. Strassler, DMD, Professor
Division of Operative Dentistry, Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School