Tooth Bleaching 

Patient Teaching: Tooth Whitening

Everybody loves a bright white smile, and there are a variety of products and procedures available to help you improve the look of yours. Many people are satisfied with the sparkle they get from brushing twice daily with a fluoride-containing toothpaste, cleaning between their teeth once a day and the regular cleanings at your dentist's office. If you decide you would like to go beyond this to make your smile look brighter, you should investigate all of your options.

You can take several approaches to whiten your smile:

 In-office bleaching At-home bleaching Whitening toothpastes

Talk to Your Dentist

You may want to start by speaking with your dentist. He or she can tell you whether whitening procedures would be effective for you. Whiteners may not correct all types of discoloration. For example, yellowish-hued teeth will probably bleach well, brownish-colored teeth may bleach less well, and grayish-hued teeth may not bleach well at all. Likewise, bleaching may not enhance your smile if you have had bonding or tooth-colored fillings placed in your front teeth. The whitener will not effect the color of these materials, and they will stand out in your newly whitened smile. In these cases, you may want to investigate other options, like porcelain veneers or dental bonding.

 

You also may want to speak with your dentist should any side effects become bothersome. For example, teeth can become sensitive during the period when you are using the bleaching solution. In many cases, this sensitivity is temporary and should lessen once the treatment is finished. Some people also experience soft tissue irritation—either from a tray that doesn't fit properly or from solution that may come in contact with the tissues. If you have concerns about such side effects, you may want to discuss them with your dentist.

Dental Office Bleaching

There are two effective bleaching methods commonly used by dentists in the dental office–the in-office "power" bleaching and laser bleaching.

Dentist In-Office Power Bleaching

The in-office "power" bleaching is one of the quickest and most effective ways to whiten teeth but requires a session at the dentist's office. The dentist isolates and protects your lips, gums, and inside lining of your mouth. Next, a powerful bleaching agent is applied to the teeth. Finally, a powerful light source is applied which completes the procedure by activating the bleaching agent.

While this provides one of the best results of any bleaching methods, it is moderately expensive, ranging from $300-$600 per arch or $600-$1200 for all of your teeth. (In dental terms an arch is either the upper set or lower set of teeth).

Laser Bleaching

Laser bleaching is a relatively new procedure only recently receiving FDA approval. Despite its high tech sounding name, laser bleaching is simply a variation of the above in-office power bleaching method.

The procedure is much the same. Gums and lips are protected and a bleaching agent is applied. The only difference is that an argon laser is used to activate the bleaching agent instead of the usual light source.

Inventors of the procedure claim that this produces a better whitening result than the conventional in-office power bleaching. We must say that the jury is still out. This is a case where clinical studies need to be performed to substantiate these claims. Laser bleaching does cost more than the typical in-office power bleaching, ranging between $750 to $2000 for a complete set of teeth.

Basics of the In-Office Bleaching

There are a number of bleaching procedures that your dentist can perform in the dental office:

For your upper arch only, the dentist can make a custom mouth piece, use a relatively high concentration of bleaching material (often called Power Bleach), and have you wear it in the office.A single tooth or set of teeth can be bleached using very high concentrations of the bleaching material. Your soft tissue is protected during these procedures.This procedure, combined with take-home dentist-dispensed bleaching is effective in the treatment of severe staining due to trauma and exposure to certain drugs such as tetracycline.The inside of a tooth can be bleached after a root canal procedure to lighten it to match the surrounding teeth.

Pros. Fast dramatic results can be achieved. You can have immediate results for a special event. Specific problem teeth can be lightened to match the rest of your smile. You are working with a professional who knows how to handle such ingredients and procedures and can integrate bleaching into your overall oral health care plan.

Cons. The cost is higher than over-the-counter products. Minor and transient tooth sensitivity can occur for some patients.

ADA News Release

A report by Dr. David Garber, a private care dentist and a clinical professor at the Medical College of Georgia School of Dentistry, suggests that combining in-office power bleaching with dentist-dispensed at home whitening trays may provide both immediate tooth shade lightening and longer-lasting effects. He also points out that the new cosmetic laser bleaching may provide a quick and longer-lasting solution for some.

The combination of power bleaching and dentist-dispensed bleaching is accomplished by treating the teeth for 30 minutes with a concentrated formula of hydrogen peroxide and then providing two weeks of treatment for 30 minutes each day at home. In-office power bleaching is characterized by rapid lightening using a high concentration of hydrogen peroxide (usually 30-35 percent) that is activated by heat and light. Patients wear a rubber dam to protect their soft tissues from the high concentration of hydrogen peroxide.

"While in-office power bleaching alone can be quick and dramatic, the patient often must come back for multiple treatments because the original stains or shade may return," said Dr. Garber. The combination of power bleaching with a 30-minute per day, every-other-day at-home bleaching schedule can achieve the most rapid and predictable results, he contends.

New laser bleaching may also be an option for some patients who want dramatic whitening effects quickly, Dr. Garber reports. Recently approved by the Food and Drug Administration for marketing as a light source, lasers have garnered a great deal of attention in the consumer press. The ADA's Council on Scientific Affairs at its January 2000 meeting issued a call to manufacturers for clinical data proving that laser bleaching is safe and effective.

Dr. Garber points out that lasers used for lightening teeth do not bleach teeth, they merely create a reaction when the hydrogen peroxide comes in contact with the laser's beam. It is this reaction that begins to lighten teeth.

"At this stage, there is little research that proves that any of these approaches are more effective than traditional bleaching methods," he reports.

Dr. Garber presented his findings at "The International Symposium on the Non-Restorative Treatment of Discolored Teeth," held last fall at the School of Dentistry of the University of North Carolina at Chapel Hill and supported by Colgate Oral Pharmaceuticals.

Source: The Journal of the American Dental Association (JADA).

Dentist-Supervised Take Home Bleaching Systems

These systems are becoming increasingly popular. With these systems the dentist makes a mold of your teeth. This mold is then used to create custom mouthpiece trays which snugly fit your teeth.

The patient takes the trays and bleaching agent home. Each night for three to four weeks the patient places bleaching agent on the trays and places the trays in his or her mouth. A brief visit or two to the dentist ensures that you are doing the home treatments correctly and allows the dentist to inspect your gums for irritation.

What we like about these systems is that the mouthpiece trays are custom made to fit each individual's mouth. This means that bleaching agent is less likely to be swallowed or less likely to seep onto and irritate gum tissue.

Second, when using these systems the patient visits the dentist office to ensure that the procedure is proceeding smoothly. This allows the dentist to make sure the custom trays are fitting properly. More importantly, it allows the dentist to check for gum irritation / damage and allows the dentist to check for tooth sensitivity. These are the most common side effects of the bleaching procedure.

These systems can cost between $250-$300 per arch ($500-$600 for all of your teeth).

For extremely yellow teeth, an in-office power bleaching is performed followed by treatment with a dentist-supervised take home system. This usually provides good results.

(Home Bleaching)Background

Home bleaching is a process in which patients apply peroxide-based gels to their discolored teeth for the purpose of lightening (i.e., whitening) them. Although there are many bleaching products, this discussion will cover only those prescribed or dispensed by the dentist and having carbamide peroxide as their active ingredient. Home bleaching first began in 1968 when an orthodontist in Ft Smith,

Arkansas noticed that patients who had been wearing orthodontic positioners filled with the oral antiseptic Gly-Oxide had their teeth whitened. Later, a pedodontist in the same city substituted Proxigel (Reed & Carnrick) for Gly-Oxide in his patients’ positioners. He did so because Proxigel (a mixture of 10% carbamide peroxide, water, glycerine, and carbopol) was thicker and, therefore, remained in the positioners longer. Clinical trials of the Proxigel technique in 1988 at the University of North Carolina found it to be effective. An average treatment time of 6 weeks usually produced a lightening of 2 Vita shades. The first commercially available home bleaching product, White and BriteTM(Omnii International), was marketed in March 1989.

Mechanism

Although not fully understood, the mechanism of bleaching appears to involve the decomposition of unstable peroxides into unstable free radicals that break down organic pigmented molecules in discolored enamel through oxidation reactions. The breakdown products are smaller, less heavily pigmented constituents.

Product Ingredients

The main ingredients in most home bleaching products are carbamide peroxide and carbopol.

Carbamide peroxide is also known as urea peroxide, hydrogen peroxide carbamide, and perhydrolurea. It is commonly present in a 10 to 20% concentration; a 10% carbamide peroxide concentration is equivalent in bleaching effectiveness to a 3.6% concentration of hydrogen peroxide. Carbamide peroxide decomposes to hydrogen peroxide and urea. The hydrogen peroxide further decomposes to water and oxygen, while the urea breaks down to ammonia and carbon dioxide.

Carbopol, a high molecular weight polyacrylic acid polymer, is usually present in a 0.5 to 1.5% concentration. It functions as a thickening agent and helps to retain the solution in the application tray. This reduces the need for frequent replenishing of the gel. Carbopol has also been found to extend the active oxygen-releasing time of the bleaching solution by up to four times. Carbopol is found in DentlBright (Cura Pharmaceutical), Rembrandt Lighten (Den-Mat), and Opalescence (Ultradent), among many others. Products that do not contain carbopol usually use some other thickening agent. Other ingredients in home bleaching products include glycerine, sodium stannate, flavorings, and phosphoric or citric acid. Because bleaching solutions are more stable at a lower pH, phosphoric or citric acid is added to lower their pH. Commonly, home bleaching products have a pH range of from 5 to 7, but some products vary from 3 to 8.5 due to variations in quality control. It is important to note that the somewhat low pH of bleaching products is quickly neutralized when the solution comes into contact with saliva.

Product Use

Shelf life is approximately 2 years and is maximized by storing the products in a refrigerator. Most of these materials are applied to the teeth by the patient using a vacuum-formed tray made of plastic. Some manufacturers recommend that reservoirs be built into the tray on the facial surfaces of the involved teeth so that a greater amount of the bleaching gel is retained for a longer period of time. When home bleaching products were first introduced, the daily application times ranged from 1 to 18 hours, with the patient replenishing the solution in the tray every ½ hour to 2 hours. Newer formulations are effective with much shorter application times. Typically, instructions now call for twice daily treatments of from 30 minutes to 2 hours. Many products give the patient the alternative of using overnight applications. Treatment times are often as short as two weeks, and nearly all patients reach their maximum lightening result by the end of six weeks. Patients can expect a lightening of from 1 to 2 Vita shades and results should be noticeable in the first few days of treatment. The retail cost of bleaching products varies greatly, from approximately 20¢ to $2.00 per mL. Bleaching results last for varying lengths of time depending on product used and the specific case, among other things. Most often, relapse occurs two or three years after treatment, however studies have found that the time may vary from 1½ to 7 years.

Examples of Carbamide Peroxide-Containing Home Bleaching Products

Product Manufacturer Available Concentrations

Nupro Gold Dentsply/Professional 10%, 15%

Opalescence Ultradent 15%, 20%

Rembrandt Lighten Den-Mat 10%

Zaris 3M ESPE 10%, 16%

VivaStyle Ivoclar Vivadent 10%, 16%

Perfecta American Dental Hygenics 11%, 16%, 21%

Platinum Colgate Oral Pharmaceuticals 10%

Ultimate White and Brite Omnii International 10%, 16%, 22%

Potential Adverse Effects

Some adverse soft tissue effects have been noted as a result of the use of bleaching products. The most common effect is an ulceration or irritation of the gingiva and mucosa. It is usually mild and transient and can easily be resolved by reducing the daily application period.1 Sore throats that have occurred with the use of bleaching agents have apparently been related to the use of cinnamon flavoring in some products to which a small portion of the population is allergic.

Bleaching agents may also affect dental hard tissues. The most common side effect is a transient and dose-related sensitivity of the teeth to thermal changes. This is believed to result from the freely diffusible nature of the solution2 rather than its low pH. Clinical

observations indicate that home bleaching with 10% carbamide peroxide solutions does not adversely affect pulpal tissues.3 Temperature sensitivity during treatment can be reduced/eliminated by treating the involved teeth with a desensitizer (e.g., D/Sense 2 [Centrix], Seal & Protect [Dentsply/Caulk], Systemp.desensitizer [Ivoclar Vivadent]) or a dentin bonding agent (e.g., Single Bond [3M ESPE], One-Up Bond F [J. Morita], Excite [Ivoclar Vivadent]).

Several studies have been done to evaluate how home bleaching agents affect enamel and dentin. One study found that bleaching agents were capable of removing the smear layer from dentin, but produced relatively few changes in the enamel.4 Studies evaluating whether or not enamel is adversely affected by home bleaching agents have produced equivocal results. While several have found no evidence of adverse effects, 2,5 others have shown that changes occur in the porosity and surface morphology of enamel.6-8

Home bleaching products can affect the bond strength of resin composite to etched enamel. One investigation found that bond strength was significantly reduced by a single, 24-hour bleaching treatment using a popular home bleaching product.9 Another study found that bleaching with 10 to 20% carbamide peroxide gels significantly decreased bond strength for up to 2 weeks after the bleaching treatment was completed.10 An initial reduction in bond strength following the use of at least some products does occur and is believed to be due to the presence of oxygen in the tooth surface, which inhibits resin polymerization. It is prudent to wait several weeks after completion of bleaching treatment before bonding to the involved teeth.

An additional problem that has been associated with home bleaching is temporomandibular dysfunction (TMD) which can occur as a result of changes in the occlusion secondary to long-term tray use. This is now less of a problem than it was originally when trays were worn for many hours each day. The problem can also be minimized by using a thin (i.e., ½-mm-thick) tray material. Thin trays not only help reduce the possibility of TMD problems, but are also more esthetically pleasing to patients. Trays should be trimmed carefully, because impingement on soft tissues can cause irritation.

Effects on Dental Materials

Studies evaluating the effects of home bleaching products on restorative materials have produced equivocal results. One study found that a home bleaching gel significantly reduced the hardness of a hybrid resin composite over a four-week treatment period. Scanning electron photomicrographs also revealed surface cracking.11 Bleaches have been found to adversely affect the color of various restorative materials, with glass ionomers exhibiting the greatest color change.12 Another investigation found that the shades of two hybrid and one microfill composite were unaffected by two home bleaching products.13 Still

another report found no adverse effects from bleaching solutions on either the surface texture or color of porcelain, resin composite, amalgam, or gold restorations.4 Some researchers believe that the tendency for bleaching agents to adversely affect restorative materials is related to their pH because greater effects have been noted for products with pH values below 5.5.

Safety

As home bleaching products grew in popularity, the American Dental Association’s Council on Scientific Affairs began to monitor their development. Its conclusion, based on the clinical data obtained over the last ten years, was that 10% carbamide peroxide products with neutral pH are safe and effective. The following 10% carbamide peroxide products have, in fact, received the ADA Seal of Acceptance: Opalescence, Colgate Platinum, Rembrandt Lighten, Patterson Brand Tooth Whitening Gel (Patterson Dental), and Nite White Classic (Discus Dental).

It is important to be aware of several things, however. Because peroxides are mutagens, some researchers and clinicians recommend that bleaching products not be used in patients who are smokers or heavy drinkers, since the carcinogenic effects may be additive. Peroxides can also delay wound healing when used for long periods. In addition to the complications of bleaching already noted (i.e, soft tissue irritation, TMD, sore throat, tooth sensitivity), nausea has also been reported.

References

1. Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int 1989;20:173-176.

2. Haywood VB, Leech T, Heymann HO, Crumpler D, Bruggers K. Nightguard vital bleaching: effects on enamel surface texture and diffusion. Quintessence Int 1990;21:801-804.

3. Haywood VB, Heymann HO. Nightguard vital bleaching: how safe is it? Quintessence Int 1991;22:515-523.

4. Hunsaker KJ, Christensen GJ. Tooth bleaching chemicals - influence on teeth and restorations [Abstract]. J Dent Res 1990;69:303.

5. Haywood VB, Houck V, Heymann HO. Nightguard vital bleaching: effects of varying pH solutions on enamel surface texture and color change. Quintessence Int 1991;22:775-782.

6. Ben-Amar A, Liberman R, Gorfil C, Bernstein Y. Effect of mouthguard bleaching on enamel surface. Am J Dent 1995;8:29-32.

7. Bitter NC. A scanning electron microscopy study of the long-term effect of bleaching agents on enamel: A preliminary report. J Prosthet Dent 1992;67:852-855.

8. Bitter NC. A scanning electron microscope study of the long-term effect of bleaching agents on the enamel surface in vivo. Gen Dent 1998;46:84-88.

9. Garcia-Godoy F, Dodge WW, Donohue M, O'Quinn JA. Composite resin bond strength after enamel bleaching. Oper Dent 1993;18:144-147.

10. Cavalli V, Reis AF, Giannini M, Ambrosiano GMB. The effect of elapsed time following bleaching on enamel bond strength of resin composite. Oper Dent 2001;26:597- 602.

11. Bailey SJ, Swift EJ. Effects of home bleaching products on resin composites [Abstract]. J Dent Res 1991;70:570.

12. Kao EC, Peng P, Johnston WM. Color changes of teeth and restorative materials exposed to bleaching [Abstract]. J Dent Res 1991;70:570.

13. Monaghan P, Lee E, Lautenschlager EP. At home, vital bleaching effects on composite resin color [Abstract]. J Dent Res 1991;70:570.

Over-the-Counter Bleaching Systems

Over-the-counter (OTC) bleaching systems are take home kits which you can buy at the local store, order by mail-order, or buy off the Internet. Usually they are relatively inexpensive costing from $29 - $175.

These kits work in a similar fashion to the dentist-supervised take home kits. A bleaching agent is applied to a mouth tray and the tray is inserted into the mouth for 2-8 hours. Treatment lasts between 2-4 weeks. We personally do not recommend these kits for two reasons:

First, many of these kits contain a standard mouthpiece tray for applying bleach onto your teeth. Because the trays are standard (made to fit everyone), they tend not to fit snugly. Consequently, you may be ingesting bleaching agent. In addition, trays which are not custom made allow bleach to seep onto and irritate gum tissue.

Second, dentists do not check your teeth and gums when you use these systems to determine if the bleaching process is proceeding safely and to ensure that you are not injuring your teeth.

While we do not recommend these systems, if you do want to take the risk and use them, we would recommend that you do the following when evaluating the wide array of take home systems available:

If possible try to use a kit that allows you to customize your mouth trays to some degree. Some systems come with moldable mouth trays which better fit your mouth. While not as good as the mouth trays created by your dentist, they are better than standard mouth trays that come with many kits. Try to find others who have used the system you plan to use and ask them how the system worked for them. While some people have been satisfied with results, others have had horrible experiences. While using the system, if you ever experience prolonged pain, changes in gum tissue color, or increased sensitivity to hot or cold foods, see a dentist immediately.

Whitening Toothpastes

A common trend has been the proliferation of toothpastes which claim to whiten teeth. Sometimes these claims mistakenly lead consumers to think that these whitening toothpastes are miracle cures.

These toothpastes are not effective at whitening the underlying tooth. What they tend to do is remove stains so that the underlying whiteness of the tooth becomes more apparent.

Think of these toothpastes as "carwashes" for your teeth. In the same way that a good car washing removes the dirt and grime on your car making it sparkle, whitening toothpastes remove stains and crud from your teeth. Smokers toothpastes work in much the same way removing tobacco-associated stains from teeth.>Be aware that there is great variability in the effectiveness of these toothpastes. Some may work extremely well while others may only make teeth appear whiter by one shade or less. To obtain a more dramatic improvement, other techniques such as bleaching are often tried.

It is important to note that while effective in removing stains, many brands of whitening and smokers toothpastes can destroy tooth enamel in the process. These toothpastes use harsh abrasives to remove the stains. Over long periods of repeated use, these harsh abrasives begin to remove tooth enamel making teeth appear yellow and causing teeth to become sensitive to cold or heat.

We suggest using one of the newer breeds of whitening toothpastes which do not contain harsh abrasives but instead use other methods for removing stains from teeth.   

Source: Dental Zone

www.saveyoursmile.com         

Alternative Methods of Whitening Teeth

For those who are disappointed with bleaching or who want a still brighter smile, several techniques exist. These techniques, however, tend to be more expensive than bleaching.

Porcelain Veneers Porcelain veneers are a popular option. These are very thin pieces of porcelain which are shaped and placed on the front of the tooth with a resin glue (analogous to placing paneling on a wall).

The advantages of veneers are that they provide for a brilliantly white smile which is resistant to discoloration and fades only very slowly over time. These veneers can be expensive, however, costing around $250 per tooth veneered.

Bonding

Another option is bonding. During bonding the dentist applies a white plastic quartz resin to the tooth. This resin is then sculpted by the dentist onto the tooth. Costing around $150 per tooth, this procedure is

less expensive than veneers but does not withstand discoloration by foods, coffee, and smoking as well as veneers do.

Caps

Caps represent a more drastic measure and are usually reserved for teeth completely broken down, teeth with fillings, or teeth having undergone a root canal. The tooth is totally ground down, an impression made, and a porcelain-metal cap added to the tooth. The cost - nearly $1500-$1800 per tooth.

Special Situations

Some people have discolored teeth as a result of their mothers having been treated with tetracycline during pregnancy or as a result of having themselves been treated with tetracycline during early childhood. These stains can be especially difficult to remove.

A common procedure is to first bleach the teeth and then apply porcelain veneers to the affected teeth. Bleaching fades the stain to a point where it will not show through the veneer when it is applied.

 

Bleaching Method

Dentist-in- office power

bleaching

Laser Bleaching

Take home dentist-

supervised bleaching

Over-the-counter

bleaching system

Type of System Traditional thermocatalytic. Active ingredient:30-35% H2O2.

Same as in-office treatment

10% carbamide peroxide with bleaching tray. 3% H2O2.  

Over-the-counter 3-step bleaching system . 6% H2O2.

Procedure Dentist isolates and protects lips, gums, and inside of mouth. A bleaching agent is applied to the teeth. Finally, a powerful light source is applied which completes the procedure by activating the bleaching agent.

Similar to in- office power bleaching with the exception that a laser is used as the light source which activates the bleaching agent.

Dentist makes custom mouthpiece trays which snugly fit your teeth. Each night the patient places bleaching agent on the trays and places the trays in his / her mouth.

Patient places bleaching agent on mouth trays that come with kit. Tray is placed on teeth overnight.

 

 

Time 1-2 hours 1-2 hours 2-3 weeks 2-3 weeksCost (per whole set of teeth)

$600-$1200 $750 to $2000 $300 to $500 $40 to 300

Advantages Produces best results. Quick and convenient.

Proponents say produces better results than dentist-in-office bleaching. Jury still out.

Nevertheless produces excellent results.

Quick and convenient.

Produces good results. Dental follow-ups during treatment make sure things are proceeding well with no adverse side effects.

Inexpensive.

Disadvantages Relatively expensive.

Relatively expensive.

Requires sticking gel and tooth tray into your mouth for two to three weeks.

Not recommended.

Very poor results.

Standard fit mouth tray can cause bleaching agent to seep onto and damage gums. No dental follow-ups to ensure that procedure is proceeding without side-effects. Requires sticking gel and tooth tray into your mouth for two to three weeks.

Safety and Effectiveness of Teeth Bleaching

Questions about the safety and efficacy of this bleaching technique have been raised by patients, dentists and recently by U.S. Food and Drug Administration. Past surveys have provided some answers to these questions.

In one such survey, 90% of the dentists who used this type of home bleaching method thought that patients were satisfied with the technique; 66% reported side effects such as gingival irritation (28%) and tooth sensitivity (23%). In another clinical trial, patients using 10% carbamide bleaching solution were pitted against patients using a placebo. A significant difference in color change was found in patients using the carbamide peroxide solution. Another study reported successful color change after 5 night-time applications of the carbamide peroxide, but there was an initial color reversion. However, the reversed color was still significantly lighter than the initial color and remained

lighter 3 months after treatment. The lasting effect of teeth bleaching, however, has not been confirmed by any documented studies, but it is generally estimated to last 1-3 years. 

The instant clinical trial by Hayward, Leonard et al. described below was undertaken with four objectives: 

to determine the effectiveness of a nightguard vital bleaching technique in a controlled population of patients over an extended period; to document any side effects of treatment with two different 10 percent carbamide peroxide solutions on gingival tissue and teeth during treatment; to evaluate the stability of the bleaching treatment over time; to determine if any side effects continued or surfaced after treatment stopped.

Thirty-eight adult patients who had expressed concern about their discolored teeth were selected for this clinical trial. These patients were divided into various categories based upon causes of staining, such as tetracycline, aging or inherent discoloration, brown fluorosis and trauma.

The patients were given a six-week supply of one of two 10% carbamide peroxide solutions (Proxigel, Reed & Carnrick or Gly-Oxide, Marion-Merrell Dow Lab, Inc.) Patients were instructed to wear the nightguard for six to eight hours at night, or to wear the guard during the day and change the solution every two to six hours.

The success of the trial including the change in color and the lasting change in color were measured by the patient's perceptions of the color of their own teeth as compared to the untreated lower arch or a standardized color shade tab. The ultimate goal of any teeth bleaching treatment is patient satisfaction which in turn is the result of patient's perception of the status of their teeth.

Conclusions

Carbamide peroxide in a 10 percent solution effectively lightened the color of teeth in 92 percent of 38 patients in a six-week period, with an average daily wearing time of seven to eight hours. Teeth stained by aging, brown fluorosis, trauma or inherent discoloration were lightened in 96.7 percent of the patients, and tetracycline-stained teeth were lightened in 75 percent of patients. Teeth stained by tetracycline did not lighten as much as teeth stained by other means.

A significant number of patients, about 66 percent, experienced transient side effects of gingival irritation and/or tooth sensitivity during treatment. However, these side effects did not prohibit continuation of treatment, and generally lasted four to seven days. The two major side

effects reported were tooth sensitivity and gingival irritation. The sensitivity of the teeth may be caused by the easy passage of the hydrogen peroxide and urea through the teeth to the pulp, resulting in a reversible pulpits.

Furthermore, the sensitivity of the gingival could have been caused either by mechanical irritation from the nightguard or chemical irritation of the solution. With adjustment of the guard, cessation of treatment, and/or decreasing the treatment time for several days, the gingival irritation resolved. No side effects occurred or returned at 13 to 25 months after bleaching.

Seventy-four percent of the group noted no noticeable decrease in the color of their teeth after 13 to 25 months with no further treatment. None of the bleached teeth that had received no further treatment had returned to the original color. Patients who had retreated their teeth did so after at least one year, and retreatment required a much shorter time than the original bleaching treatment. Three years after treatment (31 to 42 months), 62 percent of the respondents had no perceivable loss of color lightening, and no side effects had occurred.

 

Source: Haywood VB, Leonard RH, Nelson CF, Brunson WD: Effectiveness, side effects and long-term status of nighguard vital bleaching. J Am Dent Assoc 125: 1219-1226, 1994.

References

1. Haywood VB, Heymann HO. Nightguard vital bleaching. Quintessence Int 1989;20:173-176.

2. Haywood VB, Leech T, Heymann HO, et al. Nightguard vital bleaching: Effects on enamel surface texture and diffusion. Quintessence Int 1990; 21: 801-806.

3. Haywood VB, Heymann HO. Nightguard vital bleaching: How safe is it? Quintessence Int 1991; 22:515-523.

4. Albers HF. Home bleaching. ADEPT Report 1991; 2(1): 9-17. 5. Haywood VB. History, safety, and effectiveness of current bleaching

techniques and applications of the nightguard vital bleaching technique. Quintessence Int 1992;23:471-488.

6. Croll TA: Tooth bleaching for children and teens: a protocol and examples. Quintessence Int 25:811- 817, 1994

7. Haywood VB, Leonard RH, Nelson CF, Brunson WD: Effectiveness, side effects and long-term status of nighguard vital bleaching. J Am Dent Assoc 125: 1219-1226, 1994

8. Goldstein GR, Kiremikjian-Schumacher L. Kriser Dental Ctr, 345 E 24th St., New York, NY 10010. Bleaching: Is it safe and effective? J Prosthen Dent 69(3): 325-8, 1993

Studies by Tooth Bleaching System Manufacturers

The efficacy of tooth bleachers was also studied by dental product manufacturers. They concluded that their products were effective in

achieving lightening effects (1,4,5,6,9). Lightening effects were variable from individual to individual and also according to which system was used. Patient satisfaction was highest in dentist-prescribed at home systems (5,6,8). Treatment time is about five to six weeks for the prescribed in home systems.

The same results can be achieved in less time by using the in-office procedure. It must be noted that this search yielded no evidence proving the efficacy of over-the-counter type systems. They were branded as unsafe and ineffective due to their lack of studies backing up their claims. Another question that is closely related to efficacy is longevity of the achieved results. Generally, noticeable cosmetic results can be achieved but how long do they last? For both in-office and dentist-prescribed, retreatment was necessary every one to three years to maintain the initial results (2,4).

The issue of product safety is still in question by the ADA and to date, no product currently available to the public is ADA approved due to lack of substantial evidence proving their safety. But product manufacturers of bleaching products have conducted their own studies proving their safety. They cite evidence disputing bleaching agent's active ingredient( hydrogen peroxide), carcinogenic potential (1,4,8). They claim the concentrations of hydrogen peroxide in their products do no harm to gingival tissues, pulp, enamel, and restorations. Upon conducting their studies, product manufacturer's data concluded that the only side effects were unpleasant taste, slight tooth sensitivity, and minor gingival irritation. All these symptoms were reversed upon the cessation of treatment (3,4,9). (These were studies done for dentist-prescribed in-home systems).

For products used in in-office systems, the higher concentration of hydrogen peroxide caused reversible plural damage which resulted in post treatment sensitivity (7). Again, over-the-counter systems were noted as being unsafe because of their acidic and abrasive ingredients. It was also pointed out that due to lack of dental supervision and evaluation, dissolution of tooth enamel could occur if used improperly(4). Also, their potential to become abused in haste to achieve a lightening effects was noted, and use of these kinds of products can be of more harm than good.

Discussion

As the literature review progressed, it became evident that the safest and most effective methods were those conducted under dental supervision. Evaluation by a dentist is important in determining if bleaching will be effective. In contrast, OTC systems place the consumer in the role of deciding what is best for the treatment without having any real background knowledge of the subject and its potential harmful side effects. Using a dentist-prescribed system ensures that proper care and maintenance will be given to the patient. Use of OTC

does not give this assurance. Often, these systems are abused due to consumer ignorance or impatience to reach desired results. It is important that people considering tooth bleaching get evaluated and educated by a dentist as to the possible achievable results as well as to possible adverse effect of bleaching products. It would be time well spent in asking the dentist questions and receiving background information than to hastily purchase a glamorous gimmick that has not been proven to be safe and effective.

Conclusions

Dentist supervised systems have been proven safe and effective. The safety and effectiveness of OTC bleachers are undetermined. There are some adverse side effects associated with each system. Patient satisfaction is highest for dentist-prescribed in home systems.

Source: Chin Edward A, Franssen Susan, Dwan Andrew, Hufunda Joe, University of Michigan School of Dentistry.

References

1. Berry JH. What about whitener? Safety concerns explored. J Am Dent Assoc 1990 Aug;121:222-5.

2. Goldstein GR, Kiremidjian-Schumacher L. Bleaching: is it safe and effective? J Prosthet Dent 1993

Mar;69:325-8. 3. Haywood VB. History, safety, and effectiveness of current bleaching techniques and applications of

nightguard vital bleaching technique. Quintessence Int 1992 Jul;23:471-88. 4. Howard WR. Patient-applied tooth whiteners. J Am Dent Assoc 1992 Feb;123:57-60. 5. Ibsen R, Ouellet D. Rembrandt Whitening System and Quick Start versatile tooth bleaching systems. J

Esthet Dent 1991 Sep-Oct;3:169-73. 6. Reinhardt JW, Eivins SE, Swift EJ Jr, Denehy GE. A clinical study of nightguard vital bleaching. Quin

tessence Int 1993 Jun;24:379-84. 7. Shearer, AC. External bleaching of teeth. Dent Update 1991 Sep;18:289-91. 8. Simon JF, Allen H, Woodson RG, Eilgers AS. Efficacy of vital home bleaching J Cal Dent Assoc 1993

Jan;21:72-5. 9. Tam L. Vital tooth bleaching: review and current status. J Can Dent Assoc 1992 Aug;58:654-60.

 

Clinical Trial of Three

10 % Carbamide

Peroxide Bleaching Products

 

by Laura Tam, DDS, M.Sc.

 

Abstract

Background

A profusion of commercial bleaching systems exists on the market today, but there are few clinical comparisons of these systems.

Methods

In this study, three different commercial 10% carbamide peroxide bleaching systems were used by 24 patients in an overnight protocol for two weeks. Each patient used two of the bleaching products simultaneously in a sidebyside comparison.

Results

The mean onset of tooth whitening was 2.4 ± 1.7 days. Tooth sensitivity was the most frequent side effect, as 64% of the patients reported tooth sensitivity occurring after 4.8 ± 4.1 days and lasting for 5.0 ± 3.8 days. Although intrapatient differences were recorded for the three commercial 10% carbamide peroxide bleaching systems by the patients, there were no statistical differences in the time of onset of subjective tooth whitening and the onset, frequency and duration of tooth sensitivity among the three commercial bleaching systems when compared pairwise or independently (p < 0.05).

Conclusion

Selection of which bleaching product to use should be based on the concentration of the active ingredient, the viscosity of the product and other marketing features. Further research is needed to investigate the causes of tooth sensitivity and methods to reduce its severity and frequency.

Introduction

Patients today have many options to achieve a more ideal tooth colour or appearance, including bleaching, veneers and crowns. Tooth bleaching is a relatively simple and conservative option. The most popular method of tooth bleaching is the home bleaching system wherein the patient wears a custommade bleaching tray containing carbamide peroxide overnight.14

A profusion of commercial bleaching systems exists on the market today. Home bleaching systems commonly utilize carbamide peroxide to deliver a more stable form of hydrogen peroxide, the active bleaching agent. Most home bleaching systems contain 10% carbamide peroxide, but different commercial brands claim superiority based on differences in the carrier of the active ingredient, which could affect material delivery, material retention in the bleaching tray (material viscosity) or patient compliance (tooth sensitivity, material taste). Although there are a few reports that compare the different bleaching systems by listing their material marketing contents,56 clinical comparisons of different bleaching systems are rare. In this study, three commercial 10% carbamide peroxide bleaching systems were used by 24 patients in an overnight protocol maintained for two weeks to compare their subjective clinical effects.

Fig. 1: Prestudy photo of maxillary arch. Teeth were matched to the Vita shade tab A3.

Fig. 2. Post-study photo of maxillary arch. teeth were matched to the Vita shade tab  A1.

 

Materials and Methods

The bleaching treatment was performed on 24 volunteer adult dental students, staff and patients who expressed an interest in bleaching their teeth. The indications, contraindications, risks and benefits of bleaching were written into the consent form and discussed with each subject. The bleaching treatment was performed on vital teeth with no or minimal intact restorations, no or minimal dentin exposure, and no or minimal history of tooth sensitivity. The fabrication of the bleaching trays, the dispensing of the bleaching kits and the photographing the patients were personally supervised by the author. 

An irreversible hydrocolloid impression was taken of each patient's upper arch to fabricate stone study models. Reservoirs approximately 0.5 mm to 1.0 mm thick for the bleaching agent were built into the bleaching trays by first applying a photopolymerizable spacer material (LC BlockOut, Ultradent) onto the labial surfaces of the teeth to be bleached. The number of teeth to be bleached depended on the patient's smile line. Generally, teeth 14 to 24 or 15 to 25 were prepared for bleaching on the study model. The spacer was kept away (approximately 0.25 mm to 0.50 mm) from the gingival margin, the interproximal contacts and the incisal and occlusal edges. A flexible 0.9mmthick ethyl vinyl acetate bleaching tray was then vacuum formed and trimmed in a scalloped fashion to avoid all soft tissue contact.

The proprietary bleaching systems under investigation were Nite White Excel (peppermint cream flavour, Discus Dental), Platinum Professional Toothwhitening System (Colgate) and Opalescence Whitening Gel (regular flavour, Ultradent). For each patient, two bleaching systems were randomly selected and randomly designated "left" or "right". The patient was to use one bleaching system for the left side and another for the right side, thus using the two agents simultaneously. A preliminary trial using disclosing agents in one of the bleaching materials showed no significant crossover of bleaching material to the other side when the bleaching tray was fabricated as described. Furthermore, mild crossover of two bleaching materials was not a serious concern, because other teeth in addition to the central incisors were to be used for comparing the bleaching effect.Each patient received a daily log form, which clearly labeled which material was to be used for which side. The log was also to record the patient's smoking habits, the patient's coffee and tea intake, the presence or absence of restorations on the teeth to be bleached, and the presence or absence of subjective tooth sensitivity before bleaching. Patients were instructed how to place the bleaching agents into the bleaching trays. Each patient was to wear the tray for approximately 14 consecutive nights (after brushing and during sleep). Each patient was asked to record daily the duration of bleaching and any subjective evaluations or effects of each bleaching agent. Patients were advised that if they experienced tooth sensitivity or other side effects, they could reduce their exposure to the agents by reducing either the duration or the frequency of bleaching. The patients were free to discontinue the treatment at any time.

A prestudy photograph of the teeth was taken under standardized lighting conditions using the same camera and dental operatory light, with and without a matching Vita shade guide tab of the teeth to be bleached (Fig. 1). After the bleaching treatment, a poststudy photograph of each

patient was taken (Fig. 2) and the daily logs were collected. Data on the onset of tooth whitening (first patient record of subjective tooth whitening) and the onset, frequency and duration of tooth sensitivity for each bleaching agent were analyzed by ANOVA (p < 0.05). Paired ttests were also performed to compare the two bleaching agents used sidebyside on the same patient (p < 0.05).The protocol for this study was approved by the University of Toronto Office of Research Services Human Subjects Review Committee.

Results

Fifteen women and nine men participated. Their mean age was 28.5 years (range 17 to 51). They did not exhibit tooth sensitivity or recession in the subject teeth before the bleaching treatment. The patients bleached their teeth for 13.5 ± 2.9 nights. Threequarters of the patients (18 of 24) complied with the daily regimen. The other patients skipped a day or more during the treatment for sensitivity reasons. The recorded time of onset of subjective tooth whitening and the onset, frequency and duration of tooth sensitivity are listed in Table 1.Side effects of the bleaching treatment presented minimal problems to the patients. Six patients (25%) reported gum tingling, tenderness or mild sensitivity for one or two days. One patient reported a scratchy throat for one day. One patient reported sleep interruption and a sore jaw for a couple of days toward the end of treatment. Another patient reported some bruxism as a response to wearing the tray. Three patients did not like the consistency of one of the bleaching products compared with the other.Intrapatient differences in whitening effect and tooth sensitivity by the two commercial bleaching systems used by each patient were occasionally reported; however, there was no clear trend for the intrapatient differences for the bleaching agents. No intrapatient differences in tooth whitening were noted between the left and right halves. There were no statistical differences in the time of onset of subjective tooth whitening and the onset, frequency and duration of tooth sensitivity among the three commercial bleaching systems when compared pairwise (paired ttest) or independently (ANOVA).

Discussion

A placebo gel was not included in this study because it is well known that carbamide peroxide and hydrogen peroxide bleaching materials will lighten teeth significantly more than placebo materials.7-11 The patients were aware which bleaching agents they were using. It was thought that potential bias by the patients toward a particular agent would be minimal given that the agents had the same 10% carbamide peroxide concentration, the patients had no previous bleaching experience or affiliations with any of the agents, and no marketing or extraneous packaging materials were given to the patients.No attempt was made to quantify the degree of whitening achieved. Other studies have attempted to quantify tooth colour changes by using the Vita shade tab system or a colorimeter. The Vita shade tab system requires subjective shade matching, and the colorimeter has been criticized because of its technique sensitivity and need for a flat surface. In addition, small increments of change that could perhaps be measured by instruments such as a colorimeter would not necessarily indicate a clinically significant result. A clinically significant bleaching result necessitates a clear perception by the patient of a difference in tooth colour. In this study, therefore, a notation by the patient that the teeth became whiter was accepted as a clinically significant colour change.

 

Table 1. Time of Onset of Subjective Tooth Whitening and Time of Onset, Frequency and Duration of Tooth Sensitivity as Reported by Patients After Bleaching Treatment

Product  Number ofOnset of whitening (days)

Frequency of sensitivity (%)

Onset of sensitivity (days)

Duration of sensitivity (days)

Platinum  17 halves 2.6 ± 1.6 65 6.2 ± 4.8 4.4  ± 3.4Opalescence

 15 halves 2.1 ± 1.4 60 4.0  ± 3.7 6.2  ± 4.9

Nite White  16 halves 2.4 ± 2.0 62 3.9  ± 3.6 4.5  ± 3.0

Totals 24 2.4 ± 1.7 64 4.8  ± 4.1  5.0  ± 3.8

Every patient reported some degree of tooth whitening. The colour changes ranged widely from very slight to dramatic. The average onset for apparent tooth colour change was 2.5 days. An early onset of bleaching effect is desirable to encourage compliance. Four patients reported the onset of tooth whitening as occurring in localized areas of their teeth, resulting in white spots. This response to bleaching has been attributed to variations in enamel structure. 12 The visibility of the white spots diminishes over time as the dentin and the rest of the enamel become whiter and perhaps as some of the early enamel whitening regresses. Patients should be advised of the likelihood of initial white spots as a result of the bleaching treatment.

The advantages of overnight wear include greater patient convenience and improved material retention due to less salivation and less interference with the bleaching tray by the patient. Disadvantages are that overnight wear generally leads to longer contact times and does not allow the patient to monitor the side effects, such as tooth sensitivity.

Tooth sensitivity was the most significant side effect of this study. Its frequency was relatively high compared to other reported problems. Other clinical studies using 10% carbamide peroxide for overnight wear over a period of several weeks have reported a 9% to 100% incidence of tooth sensitivity. 7,13-16 Leonard and colleagues17 suggested that the only predictors for tooth sensitivity during home bleaching were frequency of application and whether the patient had sensitive teeth before bleaching. Sex, age, day or night wear pattern, dental arch, and absence or presence of abrasion, defective restorations or gingival recession had no significant effect on the development of tooth sensitivity in their study.In the present study, most reports of sensitivity were mild, transient, sporadic or continuous over a few days, and were elicited by a cold stimulus. When specific teeth were indicated, they were usually the incisors and canines; the premolars were never indicated as specifically sensitive. Two patients reported episodes of spontaneous sensitivity. Two patients reported sensitivity to heat. Five patients reported one to three days of "acute," "very," "extreme," "high" or "severe" tooth sensitivity. The mean number of days of sensitivity was 5.0 ± 3.8 days. All patients should be advised of the likelihood of tooth sensitivity as part of their informed consent. They should also be told that sensitivity could be severe enough to prevent or at least delay the completion of treatment. In other studies, 2 of 17, 4 of 10 and 4 of 28 patients discontinued their bleaching treatment as a result of tooth sensitivity. 7-16

In the present study, 25% of the patients skipped at least one day of bleaching for tooth sensitivity reasons but continued to bleach their teeth thereafter. One patient stopped treatment after 12 days because of sensitivity.The patients were generally assessed within one week of the bleaching treatment. No patients reported the persistence of tooth sensitivity after the cessation of bleaching. This is in agreement with other reports, which conclude that no longterm irreversible pulpal effects are associated with these bleaching techniques.6 Electric pulp tests have indicated no significant changes in pulp response following bleaching whether the teeth were sensitive or not.7,16 Longer exposures to bleaching agents do not appear to increase the level of tooth sensitivity. In this study, tooth sensitivity often diminished during the latter part of treatment. In one 6month clinical study, the majority of toothsensitive days occurred near the beginning of treatment and there were only zero to 20 days of total tooth sensitivity.18

Tooth sensitivity has been attributed to the permeation of the bleaching agent into the pulp.19 Fluoride gels in the bleaching trays have been recommended for treating tooth sensitivity;3 however, fluoride's action in desensitization is unknown. It could be beneficial in reducing exposure of the pulp to the bleaching agents by simply supplanting the use of the bleaching agent for that day. Fluoride and other desensitizing pastes could also theoretically reduce the penetration of hydrogen peroxide into the pulp by reducing the permeability of dentinal tubules at their orifices. Nonetheless, the best ways to reduce the pulpal inflammation causing tooth sensitivity are probably to reduce the time of exposure to the bleaching agent and to administer antiinflammatory analgesics.

Despite some reported intrapatient differences, there were no statistically significant differences among the three commercial bleaching systems with respect to tooth sensitivity.

According to information from the manufacturers, Opalescence uses glycerine and contains 20% water. Platinum has a waterbased dentifrice formulation. Nite White Excel uses a polyglycol composition and is unique because it contains no water. The water content of the bleaching agent could conceivably affect both tooth dehydration and material stability. In the present study, the different water content of the three commercial bleaching systems did not appear to affect tooth sensitivity or tooth whitening.

The pH values of the three bleaching materials were measured at room temperature by a flat surface polymer body combination electrode with an Accumet 620 pH/mV meter (Fisher). For Platinum, the mean pH was 5.90 (± 0.03, standard deviation); for Opalescence, 6.40 (± 0.09); and for Nite White, 7.43 (± 0.03). Scanning electron microscope investigations have shown slight changes to enamel surface morphology after exposure to bleaching material, particularly under more acidic conditions. The clinical significance of these changes, however, is considered negligible or minimal for bleaching treatments of normal duration when the buffering and remineralization potential of the saliva are considered. Furthermore, it has been shown that the pH of a carbamide peroxide solution increases during nightguard wear as a result of urea breakdown. The pH of the material can affect peroxide radical liberation (and hence, bleaching effect) and material stability. A sufficiently lowpH material can also open exposed dentinal tubules, resulting in increased tooth sensitivity. In the present study, the different pH values of the three commercial bleaching systems did not result in clinical differences in tooth sensitivity or tooth whitening.

The selection of a bleaching product should be based on the concentration of the active ingredient, the viscosity of the bleaching agent (higher material viscosity leads to greater material retention)24 and other marketing features. It is likely that higher concentrations of carbamide peroxide will not only whiten teeth more quickly and to a greater degree, but will also lead to increased sensitivity problems. Therefore, a balance between tooth sensitivity and tooth whitening needs to be struck for each individual patient. In Canada, a concentration of 10% carbamide peroxide is significant because formulations containing greater than 10% can be used only under the supervision of dental professionals. In the United States, only 10% carbamide peroxide formulations have received the American Dental Association Seal of Acceptance from the Council on Scientific Affairs of the American Dental Association.Bleaching methods and materials appear to be growing by leaps and bounds. This study attempts to provide some independent clinical data for dental practitioners for the most common home bleaching method using an overnight wearing regimen in a clinical setting. Further research is needed to investigate the causes of tooth sensitivity and methods to reduce its severity and frequency. 

Dr. Tam is an assistant professor in the Department of Restorative Dentistry, Faculty of Dentistry, University of Toronto, 124 Edward St. Toronto, ON M5G I G6.

The author has no declared financial interest in any company manufacturing the types of products mentioned in this article.Acknowledgments: The author thanks Mr. R. Kandola, a third-year dental student in the faculty of dentistry, University of Toronto, for his assistance in obtaining the pH measurements. 

Reprinted with permission.

Journal of Canadian Dental Association.April 1999, Vol. 65, No. 4.

References

1. Christensen GJ. Bleaching teeth: Report of a survey, 199J Esthet Dent 1998; 10:16-20. 2. Burrell KH. ADA supports vital tooth bleaching&-;but look for the seal J Am Dent Assoc 1997; 12 8:3 S5 S.  

3. Whitening products and fluorides. The Dental Advisor 1996; 13 (4):1-6.  

4. Trends in dentistry. Lighter, whiter, brighter: trends in tooth whitening products and procedures. Dental Products Report 1996; July:20-7.  

5. Freedman G, McLaughlin G. Whitening teeth: the demand is increasing. Dent Today 1996; 15:100, 104, 106, 108-12.  

6. Tooth bleaching, state-of-art ’9CRA Newsletter 1997; 21(4):1-4.

7. Gegauff AG, Rosenstiel SF, Langout KJ and Johnston WM. Evaluating tooth color change from carbamide peroxide gel. JADA 1993; 124:65-72.

8. Rosenstiel S.F., Gegauff A.G. and Johnston WM. Duration of tooth color change after bleaching. JADA 1991; 122:54-63.

9. Rosenstiel SF, Gegauff AG, McCafferty RJ and Johnston WM. In vitro tooth color change with repeated bleaching. Quintessence Int 1991; 22:7-12.

10. Matis BA, Cochran MA, Eckert G and Carlson TJ. The efficacy and safety of a 10% carbamide peroxide bleaching gel. Quintessence Int 1998; 29:555-63.

11. Ouellet D, Los S, Case H and Healy R. Double-blind whitening night guard study using ten percent carbamide peroxide. J Esthet Dent 1992; 5:79-83.

12. Haywood VB. Achieving, maintaining and recovering successful tooth bleaching. J Esthet Dent 1996; 8:31-8.

13. Haywood VB, Leonard RH, Nelson CF and Brunson WD. Effectiveness, side effects and long-term status of night guard vital bleaching. JADA 1994; 125:1219-26.

14. Reinhardt JW, Eivins SE, Swift Jr Ell and Denehy GE. A clinical study of night guard vital bleaching. Quintessence Int 1993; 24:379-84.

15. Sterrett J, Price RB and Bankey T. Effects of home bleaching on the tissues of the oral cavity. J Can Dent Assoc 1995; 61:412-20.

16. Schulte JR, Morrissette DB, Gasior EJ and Czajewski MV. The effects of bleaching application time on the dental pulp. JADA 1994; 125:1330-51.  

17. Leonard RH, Phillips C and Haywood VB. Predictors for sensitivity and irritation in night guard vital bleaching. J Dent Res 1996; 75 (Abstr. no. 2894):379.  

18. Haywood VB, Leonard RH and Dickinson GL. Efficacy of six months of night guard vital bleaching of tetracycline-stained teeth. J Esthet Dent 1997; 9:13-29.

19. Heymann HO. Bleaching of vital teeth. Quintessence lnt 1997; 28:420-7.

20. Bitter NC and Sanders JL. The effect of four bleaching agents on the enamel surface: A scanning electron microscopic study. Quintessence Int 1993; 24:817-24.

21. Ben-Amar A, Liberman R, Gorfil C and Bernstein Y. Effect of mouth guard bleaching on enamel surface. Am J Dent 1995; 8:29-32.

22. Leonard RH, Austin SM, Haywood VB and Bentley CD. Change in pH of plaque and 10% carbamide peroxide solution (luring night guard vital bleaching treatment. Quintessence Int 1994; 25:819-23.

23. Frysh H, Bowles WH, Baker F, Rivera-Hidalgo F and Guillen G. Effect of pH on hydrogen peroxide bleaching agents. J Esthet Dent 1995; 7:130-3.

24. Ploeger BJ, Robison RA, Robinson DF and Christensen RP. Quantitative in vivo comparison of five carbamide peroxide bleach gels. J Dent Res 1991.

CDA RESOURCE CENTRE

For more information on tooth bleaching techniques, products and other related issues, contact the CDA Resource Centre. The Resource Centre has information packages and textbooks on tooth bleaching. It can also do computer searches for CDA members. 

Reprinted with permission.Journal of Canadian Dental Association.April 1999, Vol. 65, No. 4.

 

CDA Statement Concerning Teeth Whiteners

Whitening or bleaching claims are being made by a number of products containing various type of oxidizing agents as the whitening or bleaching ingredient. Most of these products are in the form of a liquid or gel that is applied (directly by the dentist or by the patient) via a mouthguard tray, and worn for several hours daily; others are toothpastes, one of which may be combined with a gel, while some utilize a multi-step process consisting of a mouth-cleaning agent, a gel, and one or more polishing creams. Some products are intended to be prescribed by dentist while others are sold over the counter.

The Committee of Community and Institutional Dentistry has written to Health Canada and expressed concern that these products fall under the regulatory category of cosmetics rather than drugs. Health Canada has indicated that these products will not be reclassified.

Whitening or bleaching products may be safe and effective. However, concern has been expressed because manufacturers do not have long term safety data available. Some published scientific studies show that regular use of oxygenating agents may damage temporarily the soft tissues of the mouth, and may delay the healing of already damaged tissue. Other studies show that the use of these agents may cause varying degrees of damage to the pulp of the teeth.

CDA continues to believe that such products should be used selectively and carefully. Although light to moderate aging stains may be visibly reduced by products containing oxygenating agents, the need for longer term safety studies supports the need for a cautious approach. Candid patient disclosure and adequate advice on home care are essential if clinicians choose to use or recommend these products. CDA believes that the public should only use these products after consultation with a dentist. 

 

Approved by Resolution 97-73CDA Board of Governors

Research Reference Guide

1. Li, Y., et al., "Evaluation of A Combined InOffice and AtHome Applied Bleaching Agent," Journal of Dental Research, Volume 78, Abs. No. 312 (1999): 144.

2. Kugel, G., et al., "Effective Tooth Bleaching in 5 Days: Using a Combined In Office and AtHome Bleaching System," Compendium (Apr 1997).

3. The Dental Advisor Plus, Vol. 6, No. 5 (Sept.Oct. 1996). 

4. The Dental Advisor Plus, Vol. 7, No. 4 (Aug. 1995).

5. Barghi, N., Morgan, J., "A Transitional Treatment," Dentistry Today (Jun. 1995).

6. Godder, B., et al., "Evaluation of Two AtHome Bleaching Systems," Journal of Clinical Dentistry, Vol. V (1994): 8688.

7. Yiming, L., "Evaluation of Cytotoxicity of Rembrandt Lighten Bleaching Gel Using the Cell Counts and MTT Tetrazolium Assay," (1993). Unpublished Data Available on Request.

8. Reinhardt, J.W, et al., "A Clinical Study of Nightguard Vital Bleaching," Quintessence Interna- tional, Vol. 24 (1993): 379384.

9. Ouellet, D., et al., "DoubleBlind Whitening NightGuard Study Using Ten Percent Carbamide Peroxide," Journal of Esthetic Dentistry, Vol. 4 (1992): 8083.

10. Furnish, G.M., et al., "Success and Longevity of Home Bleaching Using 10 % Carbamide Peroxide," American Association of Dental Research, Abs. 664 (1992).

11. Lavelle, C.L.B., et al., "A Preliminary Clinical Evaluation of Rembrandt Lighten,"University of Manitoba (1992).

12. Scherer, W., et al., "AtHome Bleaching System: Effect on Gingival Tissue," (1992). Unpublished Data Available on Request.

13. Strassler, H.E., "Clinical Technique for Bleaching With the Rembrandt Whitening System and Quik Start Bleaching Gel," Journal of Esthetic Dentistry Vol. 3, No. 5 (Sept.Oct. 1991).