Bleaching at Home or at the Dentist's Office
There's nothing that radiates health, happiness and even success like a sparkling white smile. So it's no wonder many people choose whitening to improve the appearance of their teeth. In fact, whitening is one of the least expensive cosmetic remedies available to enhance a faded smile. It can be done at home or at your dentist's office, using a variety of products and techniques. But even if you are only considering an at-home whitening approach, it's best to have a dental exam first to make sure your discoloration is not due to a condition in need of treatment. Your dentist can also help you choose the most effective whitening method for your particular situation.
How Does Teeth Whitening Work?
Whitening involves applying bleach solutions to the teeth. The bleach attacks the highly colored organic molecules that lodge between the crystals of tooth enamel (the outermost tooth covering) or in the dentin (the tooth material under the enamel). It's these organic particles that give the teeth a stained appearance. For surface stains, the solution is left on the teeth usually for 30 minutes to one hour, depending on the method used. For internal stains on non-living teeth that have had root canal work, the bleach might be sealed inside the tooth. The bleaching process continues until these organic particles are rendered colorless. Bleaching works best on yellowish stains and even some brown stains, but may not work at all on gray discoloration. It's important to keep in mind that bonding material and fillings cannot be whitened with bleach. If you have these restorations in your mouth, you should consider how your teeth will look if the natural parts become whiter and the bonding stays the same.
Is Whitening Safe for My Teeth?
Generally speaking, whitening is safe because the chemicals used to attack the organic molecules do not materially affect the mineral structure of the tooth itself. There are many studies supporting the overall safety of whitening by bleaching, though it's possible to experience some temporary side effects such as tooth sensitivity. Your dentist will take precautions to protect your root surfaces to minimize your potential for tooth sensitivity.
The bleaches used most often in teeth-whitening products are hydrogen peroxide and carbamide peroxide. The latter is particularly appropriate for home-whitening products because it is a more stable compound with a longer shelf life. It can also be left on the teeth for longer periods with less risk of sensitivity. Professional bleaching solutions containing hydrogen peroxide, a faster-acting bleach, can lighten teeth up to 10 shades in about an hour, though some people may need several treatments to achieve the desired level of whitening.
What Causes Teeth Staining or Discoloration?
There are two types of tooth discoloration: Extrinsic (external or surface) and intrinsic (internal).
Extrinsic staining is caused by substances that come in contact with the tooth. Big culprits are tobacco, either smoked or chewed, and foods containing tannins such as red wine, coffee and tea.
Intrinsic tooth discoloration can happen with aging as enamel loses its youthful translucency, becoming less porous; this makes the underlying dentin more visible as it thickens and becomes more yellow over time. Intrinsic discoloration is also caused by exposure to excessive fluoride or the antibiotic tetracycline during tooth-formation, inherited developmental disorders, and jaundice in childhood. For teeth that have erupted already, the main causes of intrinsic discoloration are tooth decay, restorations, pulp death (root canal problems) and trauma to developing teeth.
It's possible to have both extrinsic and intrinsic discoloration at the same time.
What Teeth Whitening Options Are There?
Whitening methods range from powerful gels that can only be applied by a professional to lower-dose products you can use at home. In general, professional treatments will achieve quicker results but will also be more expensive.
- Professional Teeth Whitening — This process involves the use of high-concentration whitening gels that are not available over the counter, as they would be less safe or less predictable if used at home.
- In-Office Whitening Systems — Your dentist will apply a gel to your teeth and leave it on for about an hour. A heat or light source (sometimes a laser) may be used during the process to increase the bleaching action.
- Take-Home Whitening — Your dentist will give you custom-made mouth trays made of thin, flexible plastic that you will fill with whitening gel and then leave on your teeth for a prescribed period of time.
- Over-The-Counter Teeth Whitening — These products contain lower concentrations of bleach but can be effective over time if used as directed. Look for the ADA Seal of Acceptance on whitening products and consult your dentist for recommendations.
- Whitening Strips — These resemble clear adhesive bandages that are stuck onto the teeth and left there usually for 30 minutes at a time, twice a day for a week or two.
- Brush-On Whitening — These gels are painted directly onto the teeth with a small brush and sometimes left overnight.
- Whitening Gum — If you are already a habitual gum-chewer, you might want to try this relatively new form of whitening. You may need to chew up to eight pieces a day to see results.
- Whitening Toothpastes — remove surface stains and plaque with special chemical or polishing agents. Unlike bleaches, they do not change the actual color of teeth.
What Are the Risks of Teeth Whitening?
The main risk is tooth sensitivity following bleaching and that varies with a given product's concentration and the amount of time it is left on the teeth. If sensitivity does occur, it usually lasts no more than one to four days. Gums can also become irritated on contact with bleaching solutions or by an ill-fitting mouth tray. It's important to wipe off excess gel from your gums during whitening and to inform your dentist of any problems.
How Long Do the Results Last?
No matter which whitening method you choose, you will probably find that the results fade over time. Whitening usually lasts from six months to two years, though longer-lasting results have been reported.
How Can I Maintain My White Smile?
You can make the brightness last longer by avoiding the foods and habits mentioned above that cause staining. Some individuals may need a touch-up whitening treatment in the dentist's office or at home once or twice each year.