Dental Whitening and Bleaching
According to the FDA, whitening restores natural tooth color and bleaching whitens beyond the natural color. There are many methods to whiten teeth, such as brushing, bleaching strips, bleaching pen, bleaching gel, laser bleaching, and natural bleaching. Traditionally, at-home whiteners use overnight trays containing a carbamide peroxide gel which reacts with water to form hydrogen peroxide. Carbamide peroxide has about a third of the strength of hydrogen peroxide. This means that a 15 percent solution of carbamide peroxide is the rough equivalent of a five percent solution of hydrogen peroxide. Over the counter kits whiten with small strips that go over the front teeth.
The peroxide oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and bleaches stain deposits in the dentin. Power bleaching uses light energy to accelerate the process of bleaching in a dental office. The effects of bleaching can last for several months, but may vary depending on the lifestyle of the patient. Factors that decrease whitening include ingestion of ligth colored liquids like coffee, tea and red wine.
According to the American Dental Association, different whitening include: in-office bleaching, which is applied by a professional dentist; at-home bleaching, which is used at home by the patient; over-the-counter, which is applied by patients; and options called non-dental, which are offered at mall kiosks, spas, salons etc. Commercial whitening products intended for home use include gels, chewing gums, rinses, toothpastes, among others.
The ADA recommends to have one's teeth checked by a dentist before undergoing any whitening method. The dentist should examine the patient thoroughly: take a health and dental history (including allergies and sensitivities), observe hard and soft tissues, placement and conditions of restorations, and sometimes x-rays to determine the nature and depth of possible irregularities.
There are two main methods of gel bleaching—one performed with high-concentration gel, and another with low-concentration agents. High-concentration bleaching can be accomplished either in the dental office or at home. Home bleaching uses high-concentration carbamide peroxide, which is readily available online or in dental stores. This is much more cost-effective than the in-office procedure. Whitening is performed by applying a high concentration of oxidizing agent to the teeth with thin plastic trays for a short period of time, which produces quick results. The application trays ideally should be well-fitted to retain the bleaching gel, ensuring even and full tooth exposure to the gel. Trays will typically stay on the teeth for about 15–20 minutes. Trays are then removed and the procedure is repeated up to two more times. Most in-office bleaching procedures use a light-cured protective layer that is carefully painted on the gums and papilla (the tips of the gums between the teeth) to reduce the risk of chemical urns to the soft tissues. The bleaching agent is either carbamide peroxide, which breaks down in the mouth to form hydrogen peroxide, or hydrogen peroxide itself. The bleaching gel typically contains between 10% and 44% carbamide peroxide, which is roughly equivalent to a 3% to 16% hydrogen peroxide concentration.
Bleaching is not recommended if teeth have decay or infected gums. It is also least effective when the original tooth color is grayish and may require custom bleaching trays. Bleaching is most effective with yellow discolored teeth.
Power or light-accelerated bleaching, sometimes colloquially referred to as laser bleaching (a common misconception since lasers are an older technology that was used before current technologies were developed), uses light energy to accelerate the process of bleaching in a dental office. Different types of energy can be used in this procedure, with the most common being halogen, LED, or plasma arc. Clinical trials have demonstrated that among these three options, halogen light is the best source for producing optimal treatment results. The ideal source of energy should be high energy to excite the peroxide molecules without overheating the pulp of the tooth. Lights are typically within the blue light spectrum as this has been found to contain the most effective wavelengths for initiating the hydrogen peroxide reaction. A power bleaching treatment typically involves isolation of soft tissue with a resin-based, light-curable barrier, application of a professional dental-grade hydrogen peroxide whitening gel (25-38% hydrogen peroxide), and exposure to the light source for 6–15 minutes. Recent technical advances have minimized heat and ultraviolet emissions, allowing for a shorter patient preparation procedure. Most power teeth whitening treatments can be done in approximately 30 minutes to one hour, in a single visit to a dental physician.
Over many years clinical research associates (CRA) have studied the effect of light and heat on bleaching. The latest of their studies was published in the March 2003 CRA Newsletter, in which they reported on the characteristics of several in-office bleaching systems using light. The following quote includes part of the CRA conclusions from that newsletter: "Use of lights according to the manufacturer's directions did not improve whitening for any system tested." Systems tested in the CRA study were: LaserSmile, LumaArch, Niveous, Opalescence Xtra Boost, PolaOffice, Rembrandt 1 Hour Smile-Whitening Program, and Zoom. Tests on BriteSmile have not yet been completed. In these studies, light use did not speed or increase the bleaching over the use of bleaching chemicals alone. The slight difference in tooth color observed as a result of bleaching with lights and hydrogen peroxide versus bleaching with hydrogen peroxide alone appears to be temporary and caused by the light's dehydration and heating of the teeth. After a few days to weeks, there appears to be no significant shade difference between teeth bleached with lights and those bleached without lights. Although research varies as to the effectiveness of bleaching using lights, many of the lights used for in-office bleaching appear to be primarily a psychological factor for the patient.
Study shows that UV light tooth bleaching is dangerous to eyes and skin.
There are many popular natural ways with which one can whiten one's teeth. Most, if not all, natural whitening methods are extremely inexpensive, especially if compared to artificial methods, which can be extremely expensive. Some natural teeth whitening methods can be very gentle on the teeth, while others can lead to enamel damage. One efficient type of natural teeth bleaching is through the use of malic acid, a natural occurring acid in fruits that contribute to their pleasantly sour taste and is made by all living organisms. One simple way of natural tooth bleaching is by applying the pulp of crushed strawberries (which contains malic acid) to the teeth and leaving it there for five minutes. Remainings of strawberry pulp can be removed by flossing the teeth. Another way is by gently and circularly brushing one's teeth with some baking soda (an abrasive teeth whitener) using a soft toothbrush. Malic acid and baking soda are both effective whitening treatments, but should be used sparingly as both methods are not too gentle on the teeth, and could lead to enamel damage if used indiscriminately (i.e. more than a couple of times a week or so). Apples, celery and carrots also support and help whitening teeth, as they act like natural stain removers by increasing saliva production (the mouth's natural self-cleaning agent) and scrub the teeth clean. They also help maintaining a fresh breath by killing bacteria that produces halitosis. The juice of apples, especially green apples, also contains malic acid (being malic derived from the Latin word for apple mālum, as the acid was named after it). Lemons are sometimes used as a teeth whitening agent by squeezing its juice on the teeth and lightly brushing for a couple of minutes. Extreme caution should be exercised with this method as the high acidity of lemon can easily damage the enamel, much more so if it is not promptly rinsed out completely with warm water. Hydrogen peroxide, while not a food product and not strictly a natural solution, is the main ingredient of most commercial and professional dental whitening products. A solution of 3-percent of hydrogen peroxide can be used as a teeth bleaching mouthwash, but be sure to spit it all out and preferably not swallow any of it. A whitening toothpaste can be made by mixing one tablespoon of baking soda with two tablespoons of hydrogen peroxide. While some cheaper commercial whitening toothpastes do have baking soda (sodium bicarbonate) as the whitening ingredient, is not recommended for one to use a baking soda based toothpaste everyday for long periods (for the aforementioned damaging effect sodium bicarbonate may have on one's teeth).