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Bleaching (Lightening Natural Teeth)
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Lightening Natural Teeth
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A long time patient of mine has finally decided to try to lighten her upper left cuspid which radiographically shows a calcified pulp canal and whose crown is significantly darker than the adjacent teeth. The tooth has a small mesial composite but other than that is intact. My patient is interested in the simplest, non-invasive procedure to accomplish the color change. Can it be lightened with a vital bleach procedure and what is the best method to apply?
Home bleaching with a standard tray. Mark the tray with a marker on the tooth to be bleached. Have the patient place one drop on that tooth area once a day a wear for 30 minutes. Usually, within a few weeks the darker tooth will lighten more quickly and catch up with the others.
Why would anyone consider office bleaching when the home method seems so much simpler and effective? Is office vital bleaching a thing of the past?
With the evidence presently available, there seems little reason for office external bleaching as the treatment of first choice for most tooth discolorations. If home bleaching is effective, as it usually is, office bleaching is unnecessary.
Office bleaching is best suited when 1) only selected teeth need to be lightened, 2) change in tooth shade is needed quickly (large shade shifts can be achieved in only one appointment), or 3) the patient will not wear an appliance.
Internal bleaching is generally still the best treatment for lightening nonvital teeth.
Is it best to home bleach teeth rapidly or slowly?
Bleaching teeth is traumatic for soft and hard structures. Because most patients undergo it without incident does not mean the oral structures are not stressed. Generally, a longer time allows tissues to build up resistance to the insult of bleaching materials and allows the normal flora to recover between treatments. We prefer bleaching only a few hours a day and only 3 or 4 days a week to reduce unfavorable tissue response. However, patients may demand a more rapid approach.
A major side effect of bleaching rapidly is tooth sensitivity. Treatment of sensitivity involves discontinuing the bleaching process and often having the patient use fluoride in their tray until the sensitivity is reduced. It is best to wait a few weeks prior to attempting bleaching again. Discuss this with the patient.
I am concerned about overbleaching. Is it possible to overbleach teeth?
Many believe that there is "saturation point" in bleaching, after which the teeth do not become lighter. Prolonged bleaching, continued despite no further change in tooth shade, can affect the appearance of the teeth, causing them to become clear and blue. The enamel also can seem to be dissolved, away and sensitivity generally becomes acute and is harder to treat.
These changes are thought to be due to an alteration of the index of refraction of the protein surrounding the enamel rods. The protein around the matrix is thought to mineralized to a point where it is nearer to that of the enamel rods. This results in the index of refraction of the enamel rods and interrod spaced to become closer together. When the index of refraction of the components of a heterogeneous material become similar, the material appears clear, due to the reduction in light refraction. Teeth appear white rather than clear because of differences in the index of refraction of its components. We need more research in this area.
How do I prevent my patient from continuing home bleaching when I treat them with an over-the-counter product?
This can be a serious problem. Patients occasionally use over-the-counter bleaching materials for prolonged periods which can cause tooth translucency (blue appearance), and tooth sensitivity. One way around this problem is to not use OTC products. In any case, your patient should understand the value of your time and expertise. There is no substitute for patient trust and compliance with instructions.
If bleaching is done and it is not totally successful and then a bonding or veneering procedure is done, could the relapse of the tooth prematurely darken the restorations and lead to failure?
In theory, yes. This has resulted in a number of esthetic failures. Some research shows home bleaching saturates a tooth so completely it can bleach a tooth all the way through, even under a bonded veneer. This has not yet been studied with controlled clinical research, but some individual cases have worked out well in this regard.
Wouldn't bleaching and bonding in the same visit help lighten teeth more and seal out stains.
Bonding should not be done on the same visit as bleaching since the residual oxgen in the tooth from the breakdown of peroxide will inhibit resin polymerization. It is important to wait about a week prior to bonding a that tooth has been bleached.
Could home bleaching become a totally patient-controlled procedure? A company could easily market a decent over-the-counter "boil and bite" mouthguard with a tube of carbamide peroxide. What is the future of home bleaching?
The biggest reason to see a dentist is for correct examination and diagnosis of needs. Several severe problems, such as abscessed teeth, internal resorption, and caries cause discolored teeth. Although bleaching may not harm these areas, avoidance of prompt treatment while bleaching could result in their becoming more serious problems.
Properly fit of a mouthguard is also important. Although a "boil and bite" appliance may be acceptable in athletics or occasionally for severe TMJ pain, it is difficult to make one without injuring the tissues that adequately covers the facial and lingual of the teeth to hold the solution in place. Occlusion is another problem that should be handled professionally.
In addition, a dentist is needed for a baseline evaluation of tissues to provide a reference point if changes occur. If other problems unrelated to the bleaching occur, a proper diagnosis is difficult without knowing the patient's baseline (e.g., periodontal abscess, aphous ulcers, etc.).
Dentists should make efforts to educate patients about the complexities of bleaching and encourage them to undergo it only under the supervision of a dentist.
What is a fair fee for bleaching?
That depends on the difficulty of the case. Fees should be based on time and responsibility needed for treatment. Overhead costs for the average U.S. dental office are now over 70% and bleaching, as all other dental services, must reflect these costs. A typical hourly rate for dental services is $100 to $400.
A typical three-month treatment with home bleaching requires 1 to 2 hours of office time. This time plus the cost of materials would therefore result in a fee of $150 to $900 for both arches, depending on office overhead, and normally includes a one-year follow-up visit.
Internally bleaching an endodontically treated tooth (two to five visits) generally requires 30 to 90 minutes of office time, for a fee of $100–$600, plus the lingual restoration. Internal bleaching on a nonendodontically treated tooth is more difficult and would cost more. The typical all inclusive bleaching package for an A4 to A2 shift would vary based on the time needed and include a cleaning, multiple bleaching appointments, any needed direct restorations, and maintenance for a year.
Since bleaching can be inconsistent and is prone to relapse, are masking porcelain veneers a better treatment for severely discolored teeth?
The major advantage of masking porcelain veneers is control and stability of the final result. The major disadvantage is the loss of tooth structure. With sound unrestored teeth, bleaching is generally a better first attempt treatment. However, with heavily restored and discolored teeth, masking veneers are a more suitable treatment.
What product do you prefer to use for internal bleaching and where do I find it?
50% superoxol, which is available at any chemical supply (35% is available through dealers). Both work when allowed to sit in the tooth for 15 to 45 minutes; apply on a cotton pellet and use a rubber dam. I replenish it about every 10 minutes. Usually one or two appointments are necessary to maximize lightening.
Be sure to fill the canal with calcium hydroxide after each treatment; continue this for at least two days. It will neutralize any remaining acid and prevent external reabsorption.
How often can office bleaching be repeated, for how many times, and can the different bleaching techniques be mixed before making a decision to discontinue all bleaching?
Office bleachings are generally scheduled 1–3 weeks apart. Occasionally, external office bleaching is done repetitively (i.e., over a dozen times). However, if there is no improvement after the third treatment, try a different approach. Home bleaching, due to its ease of use, is the treatment of first choice for most patients. It can be repeated a number of times with no known ill effects. Although the limits for home bleaching have not been established, when improvement stops, stop treatment. Both treatments can also be combined (Called Dual Bleaching or Power Bleaching).
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