Dental Bleaching & Whitening

Dental bleaching, also known as tooth whitening, is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. A child's deciduous teeth are generally whiter than the adult teeth that follow. As a person ages the adult teeth often become darker due to changes in the mineral structure of the tooth, as the enamel becomes less porous.


Teeth can also become stained by bacterial pigments, food-goods and vegetables. Certain bacterial medications (like tetracycline) can also cause teeth stains or a reduction in the brilliance of the enamel. Tooth bleaching is not a modern practice. Ancient Romans, for example, utilized urine as a product to make and keep their teeth whiter.

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 vegetables and the ingestion of light colored liquids like coffee, tea and red wine. Dentures can also be whitened using denture cleaners.

Internal staining of dentin can discolor the teeth from inside out. Internal bleaching can remedy this. If heavy staining or tetracycline damage is present on a patient's teeth, and whitening is ineffective, there are other methods of whitening teeth. Bonding, which also masks tooth stains, is when a thin coating of composite material is applied to the front of a person's teeth and then cured with a blue light. A veneer can also mask tooth discoloration.

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 has published a list of accepted over-the-counter whitening products to help people choose appropriate whitening products. There is also the option of effectively and naturally whitening one's own teeth by natural teeth bleaching methods.

The ADA recommends having 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 burns 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.

Low-concentration whitening is far less effective, and is generally only performed at home. Low-concentration whitening involves purchasing a thin mouthguard or strip that holds a relatively low concentration of oxidizing agent next to the teeth for as long as several hours a day for a period of 5 to 14 days. Results can vary, depending on which application is chosen, with some people achieving whiter teeth in a few days, and others seeing very little results or no results at all. Dentists as well as some dental laboratories can make custom fitted whitening trays that will greatly improve the results achieved with an over-the-counter whitening method.

A typical course of bleaching can produce dramatic improvements in the appearance of most stained teeth; however, some stains do not respond to bleaching. Tetracycline staining may require prolonged bleaching, as it takes longer for the bleach to reach the dentin layer. Case studies have been performed on people with tetracycline stained teeth. They used custom bleaching trays every night for 6 months and saw dramatic results and improvement. White-spot decalcifications may also be highlighted and become more noticeable directly following a whiting process, but with further applications the other parts of the teeth usually become more white and the spots less noticeable. 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. However, whitener does not work where bonding has been used and neither is it effective on tooth-color filling. Other options to deal with such cases are the porcelain veneers or dental bonding.
Although there is a wide range of whitening products and techniques available, the results after using them may vary from very positive results to almost non-existent results.

The whitening shade guides are used to measure tooth color with the Vitapan Classic Shade Guide being the most widely used with 16 shades. These shades determine the effectiveness of the whitening procedure, which may vary from two to seven shades.
Treatment times and recommendations are dependent on the condition of a person’s teeth at time of treatment.

The use in cosmetic dentistry of concentrations above 0.1% of hydrogen peroxide is illegal in the UK, but almost all teeth whitening methods use many times this concentration. Dentists as well as whitening clinics in the UK ignore this law and so far this law has not been enforced.

Light-accelerated bleaching
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.

Natural Methods
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, [11] [12] 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. Remaining 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,[13] 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. 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).

Side effects of teeth bleaching include, but are not limited to:
•    Chemical burns from gel bleaching (if a high-concentration oxidizing agent contacts unprotected tissues, which may bleach or discolor mucous membranes), sensitive teeth
•    Over bleaching known in the profession as "bleached effect", particularly with the intensive treatments (products that provide a large change in tooth color over a very short treatment period, e.g., 1 hour)
•    Pain if you have "sensitive teeth" caused by open dentinal tubules.
•    Risk of increased hot/cold sensitivity.
•    Increased risk of tongue cancer.
A recent study by Kugel et al. showed that nearly half the initial change in color provided by an intensive in-office treatment (i.e., 1 hour treatment in a dentist's chair) may be lost in seven days. Rebound is experienced when a large proportion of the tooth whitening has come from tooth dehydration (also a significant factor in causing sensitivity).  As the tooth rehydrates, tooth color 'rebounds' back toward where it started.

Home tooth bleaching treatments can vary slightly reduce tooth enamel. There have been long term Tetracycline studies done where patients received high concentration bleach, over night, for 6 months. These studies show that even over long term exposure, the amount of reduction in tooth enamel is insignificant.
The side effects that occur most often are a temporary increase in tooth sensitivity and mild irritation of the soft tissues of the mouth, particularly the gums.[18] Tooth sensitivity often occurs during early stages of the bleaching treatment. Tissue irritation most commonly results from an ill-fitting mouthpiece tray rather than the tooth-bleaching agent. Both of these conditions usually are temporary and disappear within 1 to 3 days of stopping or completing treatment.
Individuals with sensitive teeth and gums, receding gums and/or defective restorations should consult with their dentist prior to using a tooth whitening system. People who are sensitive to hydrogen peroxide (the whitening agent) should not try a bleaching product without first consulting a dentist. Also, prolonged exposure to bleaching agents may damage tooth enamel. This is especially the case with home remedy whitening products that contain fruit acids.

Bleaching is not recommended in children under the age of 16. This is because the pulp chamber, or nerve of the tooth, is enlarged until this age. Tooth whitening under this condition could irritate the pulp or cause it to become sensitive. Tooth whitening is also not recommended in pregnant or lactating women.
Tooth whitening does not usually change the color of fillings and other restorative materials. It does not affect porcelain, other ceramics, or dental gold. However, it can slightly affect restorations made with composite materials, cements and dental amalgams. Tooth whitening can restore color of fillings, porcelain, and other ceramics when they become stained by foods, drinks, and smoking, among other activities.

Although some over-the-counter bleaching products contain carbamide peroxide, most of them are H2O2 based, which has the potential to interact with DNA. Although there is concern with H2O2 carcinogenicity, there is insufficient research to support a conclusion. What the studies have been able to show is that H2O2 is both an irritant and cytotoxic. Clinical studies have found a higher occurrence of gingival irritation when patients use bleaching materials with higher peroxide concentrations.

Internal bleaching
Internal bleaching procedures are performed on devitalized teeth that have undergone endodontic therapy (a.k.a. "Root Canal") but are discolored due to internal staining of the tooth structure by blood and other fluids that leaked in. Unlike external bleaching, which brightens teeth from the outside in; internal bleaching brightens teeth from the inside out. Bleaching the tooth internally involves drilling a hole to the pulp chamber, cleaning, sealing, and filling the root canal with a rubber-like substance, and placing a peroxide gel into the pulp chamber so the gel can work directly inside the tooth on the dentin layer.  In this variation of whitening the peroxide is sealed within the tooth over a period of some days and replaced as needed, the so called "walking bleach" technique.

Various chemical and physical agents can be used to whiten teeth. Toothpaste typically has small particles of silica, aluminum oxide, calcium carbonate, or calcium phosphate to grind off stains formed by colored molecules that have absorbed onto the teeth from food. Unlike bleaches, whitening toothpaste does not alter the intrinsic color of teeth.

Bleaching solutions contain peroxide, which bleaches the tooth enamel to change its color. Off-the-shelf products typically rely on a carbamide peroxide solution varying in concentration from 10% to 44%. Bleaching solutions may be applied directly to the teeth, embedded in a plastic strip that is placed on the teeth or use a gel held in place by a mouthguard.

The US FDA only approves gels that are under 6% hydrogen peroxide or 16% or less of carbamide peroxide. The Scientific Committee for Consumer Protection of the EU also considers gels containing higher concentrations than these to be unsafe.

Dr. Gardner’s office located at 8200 Carmel Ave NE Suite 101 is fully equipped to cater patients with different dental problems. As an experienced dentist in Albuquerque, Dr. Gardner does assure that people in the central New Mexico area will be provided with the best dental tooth whitening services, but also other dental services including dental implants, dental bridgework, dental filings, dental cleaning and providing well-fitted dentures.

If you are in the New Mexico area please call 505-828-2669 to discuss available treatments and dental makeover procedures, you can visit Dr. Gardner’s office and he will help you achieve the best smile you will ever have.


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