Tooth Whitening Procedures (Bleaching) are one of the most popular procedures in dentistry today. Prior to attempting any of the Bleaching methods available nowadays, you should definitely have a thorough conversation with your dentist. He or she can tell you whether whitening procedures would be effective for you. Whiteners may not correct all types of discoloration. For example, yellow-ish hued teeth will probably bleach well, brownish-colored teeth may bleach less well, and grayish-hued teeth may not bleach well at all. Likewise, bleaching may not enhance your smile if you have had bonding or tooth-colored fillings placed in your front teeth. The whitener will not effect the color of these materials, and they will stand out in your newly whitened smile. In these cases, you may want to investigate other options, like porcelain veneers or dental bonding.
The exact mechanism by which bleaching removes tooth stains is not completely understood. The basic chemical reaction is an oxidation process whereby hydrogen peroxide is broken down to water molecules and active oxygen. The active radicals break down long-chain molecules containing chromogens (staining molecules) to short-chain molecules, which are optically inert.
Carbamide peroxide (also known as perhydrol urea or urea peroxide) consists of hydrogen peroxide combined with urea, which is deemed to be somewhat safer, because pure hydrogen peroxide (at least at concentrations where it is effective as a whitening agent) can diffuse through enamel and dentine and into the pulp chamber. Within 5 minutes of hydrogen peroxide exposure, peroxide molecules can be detected in the pulp chamber. Carbamide peroxide will achieve the same effect, however.
Hydrogen peroxide that is used for whitening is used a lower concentrations, however it is always formulated with an "activator" that will increase the peroxides whitening efficiency when exposed to a particular wavelength of light.
There are several different whitening procedures and products available today: some are available over-the-counter, others are only available through your dentist, yet again others need to be done in your dentists office. We will examine some of these different procedures below.
In-Office Whitening Procedures
If you are a candidate for bleaching, your dentist may suggest a procedure that can be done in his or her office. This procedure is called chair side bleaching and may require more than one office visit. Each visit may take from 30 minutes to one hour.
During chair side bleaching, the dentist will apply either a protective gel to your gums or a rubber shield to protect the oral soft tissues. A bleaching agent is then applied to the teeth, and a special light may be used to enhance the action of the agent.
Gas Plasma and LED Lights
This is another very popular whitening system. This system is marketed under the trademark name BrightSmile®. The BrightSmile® System utilizes a propriety gel, which consists of a 15% hydrogen peroxide solution, buffered at a fairly neutral pH. According to BrightSmile®, the gel also contains a patented photo-initiator, which assists in chromophore destruction at the tooth's surface and this is what allows a more efficient bleaching process. However, the current protocol also calls for the addition of an "accelerator" during the second or third application, which increases the effectiveness of the gel.
The light unit is not a laser, however, it is a filtered LED (Light Emitting Diode) or Gas Plasma Light, which is filtered to emit light in the blue-green region of the electromagnetic spectrum (approximately 400-500 nm). At that frequency the "photo initiator" in the gel is activated and acts as a catalyst in the whitening process.
This whitening process takes about 60 minutes, which is broken down into three twenty minute applications during which the whitening gel is exchanged. Again, your dentist may recommend a home bleach follow-up regiment.
Laser Systems
Lasers have been used during tooth whitening procedures to enhance the action of the whitening agent. No whitening products using lasers, however are currently are on the ADA list of Accepted products. In laser bleaching, the dentist cleans your teeth with a sandy, pumice-like material to remove plaque. Then a peroxide-based gel is applied, followed by laser light to activate the gel and initiate the chemical reaction that produces the whitening effect (the laser doesn't actually penetrate the teeth). The procedure takes about an hour and a half and offers immediate results, although it may take more than one session to achieve the desired level of bleaching.
One of the most frequently used Laser systems is the LaserSmile™ System. The laser unit itself (pictured above) utilizes a T-Diode system to produce a laser light in the 800nm range, which is near the infrared region of the electromagnetic spectrum. LaserSmile™ uses a 35% peroxide gel, which, according to the company, will be "photo activated" through the laser and produces thus a more efficient whitening gel.
Since the laser operates in the infrared spectrum, heat generation in the teeth has been a concern. It has been shown, however, that the exposure time of the individual teeth to the laser is too short to cause any thermal damage. The entire whitening process takes only 24 minutes. Your dentist may recommend a follow up home bleach regiment.
Metal Halide Lights
These lights are being used in the Zoom!™ System, which has gained a lot of popularity recently. The Zoom!™ System is distributed by Discus Dental and includes their own proprietary whitening gel as well as the light unit.
The gel is a "light-catalyzed" peroxide gel. It actually consists of two components: a 32% peroxide gel and a propriety "activator", which are mixed together just prior to the application. The resulting gel is approximately 25% in concentration at a fairly neutral pH.
The Zoom!™ Light unit produces a mercury metal halide light in the in the violet region of the electromagnetic spectrum (approximately 350-400 nm), according to the company's disclosures. The light also features an infrared filter, which helps minimize the thermal build up. It is believed that certain elements are activated in the whitening gel at that wavelength, which increases the efficiency of the whitening gel dramatically.
The treatment time is exactly the same as in the BrightSmile® System. The whitening process takes about 60 minutes, which is broken down into three twenty minute applications during which the whitening gel is exchanged. The Zoom!™ System recommends that you follow up with their home bleach system.
Halogen Lights
Halogen Lights are predominantly used in the LumaArch™ Whitening System. This is a very fast whitening system. This system uses also a proprietary hydrogen peroxide based whitening agent called LumaWhite™. In this system a powder and liquid are mixed, yielding a gel with a 35% hydrogen peroxide concentration with some mild acidity (pH 5.5).
The light unit used is a Xenon-Halogen light, emitting a light in the blue-green spectrum, approximately in the 400 to 580 nm range. Again, it is the company's belief that at that frequency a component in the whitening compound gets "activated" enhancing its whitening effect dramatically.
As already mentioned, this is a very fast whitening system and is comparable to the laser systems in speed. Actual whitening time is 24 minutes. Although not company protocol, your dentist may still recommend to follow up with a home bleach system.
Plasma Arc or LED Curing Lights
Plasma Arc or LED Curing Lights are used or recommended by several whitening systems. These systems are in particular the Rembrandt® Sapphire™ System, the Niveus™ System and the Opalescence® Xtra® Boost™ System. All of these systems utilize a hydrogen peroxide based whitening agent ranging from 27% to 38%.
Plasma Arc Lights or LED Curing Lights (pictured above) utilized for whitening all emit light in the blue-green spectrum, which, again, activates certain key elements in each of these whitening systems that make the whitening process more efficient.
The cumulative whitening time for all three systems is between 45 and 60 minutes. Beyond that, your dentist may still recommend to follow up with a home bleach system.
Home Whitening (Bleaching) Systems
Several types of home whitening systems are available, which all exhibit various degrees of effectiveness and efficiency. Below is a brief description of each of these systems.
Professional Home Whitening System
These are whitening systems that you can only obtain from your dentist and are probably the most frequently used systems. He will make a custom plastic tray that fits precisely over your teeth and supply you with gel syringes that you will inject into the trays prior to application. The gel utilized, is a Carbamide Peroxide gel, which is available in concentrations from 16% to 40%. Your dentist will determine which gel concentration is right for you to start with.
You utilize this system at your own convenience at home usually only for a brief session at a time. Improvements that can be seen range from several hours to several weeks, depending on factors only your dentist can explain to you after a closer examination of your teeth.
Over-The-Counter Systems
These are trays and gels that are available over-the-counter in your local drug stores. Needless to say, the trays are generic and usually not custom fitted, and the gel concentration is less than what can be obtained by prescription from your dentist. Some people have claimed some success with these systems.
Disposable Whitening Strips
This is also an over-the-counter system that is fairly new on the market. Their effectiveness has therefore not been thoroughly evaluated yet. These are strips of flexible plastic that have an adhesive on one side that makes contact with your teeth. While they are worn, a whitening compound is being released. These are worn for the same duration as the above trays would, however their disposability eliminates the need for a re-usable tray.
Whitening Toothpastes and Rinses
These are also over-the-counter preparations that all have a low concentration of carbamide peroxide in them. Positive results have only been sporadic at best with these products, however they may aid in maintaining the whitening that has been achieved by other whitening methods.