It seems like every day a new bleaching product is coming to market, and deciding which product to use can be confusing. I will explain the different types of stain that occur in and on teeth, and the best bleaching options for each scenario.
Tooth whitening removes intrinsic and extrinsic staining. Many tooth-whitening options are currently available, including in-office whitening treatments and home-use products that can be professionally dispensed or purchased over the counter.
Extrinsic, or surface stains, are non-developmental stains on the surface of teeth caused by tobacco use, drinking coffee, tea and red wine and some pigmented foods. Whitening toothpaste removes superficial stains and smoothes out the microscopic defects on the surface of enamel because they contain fine rounded abrasives, causing more reflection and a whiter appearance. Toothpaste with amorphous calcium phosphate (ACP) actually fills in the microscopic surface irregularities, making the teeth appear whiter. I recommend using whitening toothpaste on an alternating basis with a non-whitening toothpaste, as overuse may lead to premature wear of the enamel near the root of the teeth, actually making them appear darker as a result of more of the dentin showing through the enamel. Some mouthrinses and toothpaste contain hydrogen peroxide, but they are in low concentrations and are in contact with the tooth surface for only short periods of time.
Instrinsic, or dentin staining, may be due to systemic conditions, the use of medications during or after tooth development (e.g. minocylcine, tetracycline), childhood diseases, infection or trauma to a primary tooth while the permanent tooth is developing. Tooth-whitening agents contain either carbamide peroxide or hydrogen peroxide, and recently agents containing enzymatic whiteners have been introduced. Both hydrogen peroxide and carbamide peroxide work in the same manner. Carbamide peroxide actually breaks down into hydrogen peroxide and urea. It is actually the hydrogen peroxide that is responsible for the whitening effect.
Where do the stains go?
This is a great question, the hydrogen peroxide actually diffuses through the enamel and then oxidizes (breaks down) the stain molecules, that results in the stain molecules becoming so small they are invisible to the naked eye. Surfactants in the whitening agents work to lift off the surface stains.
Does bleaching whiten crowns or fillings?
No, bleaching agents only whiten natural teeth, they do NOT whiten caps, crowns, veneers, fillings, or dentures. Also, if you have dental work to be treated, consult with your dentist before use.
What about the lights I see in the malls?
The bottom line with light assisted bleaching is that there is no definitive research to backup the use of a light. Some research shows it speeds up the effect, other show it has no visible effect. I believe that marketing by the developers of the bleaching agents have made people perceive they are getting a faster or deeper bleach. The reality is, patients get a lot of rebound after those treatments and the added cost of using the light does not make it better. These patients still need custom bleaching trays after bleaching with the light. Point Family Dentistry does not offer or promote light based bleaching because the results did not meet the “marketing hype” promised by the companies. Do not feel that you are getting treated improperly if your dentist does not recommend or utilize a light during in office bleaching. In fact, the light may increase the temperature inside the teeth, leading to more sensitivity.
What about over-the counter (OTC) bleaching products found in drugstores?
These products work well for many patients, and I often recommend the use of these as a first line approach to bleaching. These products come in standard trays, strips or paint on applicators and contain either hydrogen or carbamide peroxide in lower concentrations than in in-office agents. The results achieved with these strips are equal to those of in-office treatments, but they take much longer to achieve. The issue I have with these products is that a patient does not have a diagnosis for their tooth discoloration, and these products will not work well for all types of stain. These strips typically only cover the six front teeth, and only the teeth in contact with the strip will be bleached. Patients with misaligned teeth are not good candidates for strips because only the portions of the teeth in contact with the bleaching strip will whiten. If you choose to use OTC whitening agents be sure to be supervised by your dentist, and have a check up to make sure you don’t have any undiagnosed cavities.
As a side note, Crest™ offers a professionally dispensed product, Crest Whitestrips Supreme™. These strips can only be dispensed by a dentist and contain a higher concentration of carbamide peroxide, more strips per box (84 strips-42 upper and lower strips), and are larger, extending beyond the front six teeth.
What is in-office Bleaching?
In-office bleaching treatments typically use a higher concentration of hydrogen peroxide for a more rapid effect. The teeth are isolated with a rubber dam barrier device to protect the gums, because the concentration of bleaching agent is much higher. The agents can cause gingival irritation, sloughing or burning, so isolation of the gingival tissues is an important step in the in office bleaching process.
Why do you fabricate custom trays for at home bleaching?
The trays are fabricated using molds of your teeth, and trimmed to cover the teeth only, avoiding the gums. These trays fit intimately with your teeth, and limit the amount of bleaching agent that leaks out, and maximizing the contact of bleach with the teeth.
Is bleaching permanent?
No, typically stains will reform over time, and does need to be maintained with the use of a whitening toothpaste and yearly touch up bleaching to maintain the whitening effect. For patients with custom bleaching trays, touch up kits can be purchased at a reasonable cost from your dentist. In-office bleaching has shown a relapse of 41% at one year, while tray bleaching shows a relapse of 26% at 18 months. There have been mixed reports about staining susceptibility after bleaching, and it is best to avoid high staining foods and drinks while bleaching and some time after completing your bleaching process.
Will my teeth be sensitive?
Tooth sensitivity is the most common side effect associated with tooth whitening, and is most likely caused by dehydration. Sensitivity has been reported in 18-78% of patients, and is typically transient with no long term effects. Sensitivity can be managed by using a desensitizing agent, such as potassium nitrate and/or fluoride. Using fluoride gel or Sensodyne™ toothpaste in the tray 10-30 minutes before bleaching can reduce sensitivity. Using a lower concentration of hydrogen (or carbamide peroxide) may also reduce sensitivity if you are especially prone to sensitive teeth. Some of the bleaching agents contain both potassium nitrate and fluoride, and have been shown to reduce sensitivity.
Will my gums become sore when bleaching?
The higher the concentration of bleaching agent, the higher the incidence of both sensitivity and gingival irritation. If you have preexisting gingival irritation or gingivitis, it is important to get the gums healthy before beginning any bleaching regimen. If you experience gingival irritation, burning or sloughing, stop using the agent until the issue has been resolved and the dentist decides to resume treatment or make a modification to your tray or concentration of bleaching agent.