How does teeth whitening work?
Professional teeth whitening service in north Brisbane, Chermside West
Arthur Walsh has many years of experience of whitening teeth with over a thousand cases of teeth whitening completed.
Before you can choose whether or not tooth whitening is for you, you need to be confident that you are dealing with proven experts in the field. You also need enough background information to understand your options before you can make an informed choice as to which tooth whitening option may be best for you.
The article below explains why teeth discolour, how you can whiten them, some short-cut techniques to avoid, and the science behind the process. Questions such as “Is teeth whitening safe?”, “What about fillings?”, and “Are there any side effects?” are discussed.
What makes our teeth discolour?
The original inherent colour or shade of your teeth is dependent upon the natural pigment molecules within each tooth. After eruption of the tooth into the mouth as a young child, external stains absorb into the tooth structure and become intrinsic stains of the tooth which add to the colour (or darkness). An intrinsic tooth stain is made up of pigment and stain molecules which absorb certain wavelengths of light and reflect others. This is responsible for the darkness or lightness of your teeth.
As more pigment and stain molecules enter each tooth over time, they join together to create larger molecules or clsters. The larger these components become the darker they appear. Overall the combination of the original pigment molecules; the accumulation of intrinsic stain molecules; and the joining of stain molecules into larger and larger structures are responsible for the slow progressive darkening of our teeth over time.
As well as the colour change that occurs due to these large molecules, the joining of them together creates a tightly packed network of stain and pigment components within the microstructure of your teeth. If we are to bleach a tooth, any bleaching product must be able to penetrate this tight meshwork as well as break down the large stain producing molecules.
How does teeth whitening work?
All teeth whitening processes in today’s market rely on an active ingredient of hydrogen peroxide. Breakdown of hydrogen peroxide results in the release of water, hydrogen ions and bleaching factors (molecular oxygen, oxygen ions and free radicals).
There are two very important processes that result from the release of these bleaching factors:
- Oxygenation: whereby some of the stain molecules are physically removed from within the tooth stucture. This not only removes some of the stain, thereby lightening the tooth, but more importantly it opens the way to allow for further penetration into the tooth microstructure by bleaching factors and results in the removal of more and more debris and stain as the treatment progresses.
- Conversion: this involves the breakdown of deeper, large, long chain, dark molecules by free radicals. These radicals act to break the large pigment and stain molecules into smaller components which do not absorb light and so appear colourless or white.
Therefore, predictable and effective teeth whitening is dependent upon the ability of bleaching factors to penetrate deeply into the microstructure of teeth.
Dentists commonly find that single visit in-chair power bleaching of ALL TYPES, regardless of the strength or brand of bleaching gel, has a high incidence of unpredictability due to the inability of the bleaching factors to penetrate into the deeper parts of the tooth. If the microstructure of a tooth is compacted with debris it is not permeable to the beaching factors. It takes sustained treatment over a period of time for the effective removal of micro-debris via oxygenation. If the pathways into the tooth microstructure are not cleared during a short treatment period, the free radicals will be unable to get to the large darkening molecules deep within the tooth.
What is the best way to whiten teeth?
The permeability of tooth microstructure to bleaching factors is the primary determinant of how successful a tooth whitening process will be. If bleaching factors have free access and adequate time to saturate deeply into the microstructure of the tooth, causing removal of debris and stain and the conversion of large, dark, long chain, molecules to small, colourless or white molecules, whitening will be remarkably successful – every time.
With years of experience and over a thousand cases of teeth whitening completed, we have found the best tooth whitening system available on the market is KOR Whitening Deep Bleaching. This is because this method of whitening focuses on the conditioning of teeth (removal of packed debis within the tooth microstructure). Kor whitening conditions teeth much more than typical whitening, so not only are the teeth much whiter after at-home whitening they are also extremely “conditioned”. Bleaching factors from the chemically accelerated in-chair peroxide can then flood the tooth microstructure for a highly effective end result.
What are my options for teeth whitening?
There are three options for teeth whitening; home treatment, in chair treatment and combination treatment.
The Pola take home kit includes your custom made trays, two large syringes of Pola whitening gel, a protective box for your trays, sensitive toothpaste, soft brush and of course your follow up appointments. The Pola take home kit produces very predictable results.
The Pola in-chair whitening treatment requires an appointment that takes between 1 ½ to 2 hours. From experience we do not generally recommend this treatment on its own as the treatment by itself can be unpredictable.
The Pola combination treatment involves approximately 3 days of home whitening followed by an in-chair whitening treatment. This treatment produces very predictable results and is perfect for patients who do not wish to do home whitening for 2 weeks.
What is the best age to whiten teeth?
The microstructure of younger teeth is much more permeable to bleaching factors than that of older teeth. So, generally speaking, younger teeth can get very white very rapidly. In fact whitening is probably most effective at about age 14. Older teeth can still be whitened considerably but more attention to technique, and often more time, is required to produce the desired result.
Is all dentist applied teeth bleaching the same?
Unfortunately the answer to this is “no!”
Most teeth bleaching products do not place enough emphasis on the conditioning of teeth and hence usually have unpredictable results depending on the inherent permeability of the particular patient’s tooth structure.
As discussed above, all exclusively in-chair treatment systems will have unpredictable results for the same reason.
A further factor with at-home bleaching is the accuracy of the tray fit. Poorly fitting trays, or trays that fit but leak, will result in mediocre results. This is because gel can easily leak out, and just as importantly saliva can leak in. Both saliva and the fluid that exudes from between your gums and teeth (crevicular fluid) contain peroxidase enzymes that naturally destroy the peroxide on contact. These enzymes break the peroxide down to only water and oxygen (not to the ions and radicals required for the bleaching process).
What about shopping centre or beauty salon teeth whitening?
All tooth whitening products on the market today are based on hydrogen peroxide and its active breakdown products. However, it is not particularly the product itself but how it is effectively delivered that determines what the result will be. Adequate oxygenation of the tooth microstructure takes considerable time, generally days to weeks. If the enamel surface is not permeable to bleaching factors then any whitening result will be minimal. This is a problem with many in-chair shopping mall type procedures which have a contact time of 15-20 minutes, often for a single application. The penetration of bleaching factors for such treatments is likely to be minimal.
The other factor with these types of systems is keeping the gel in contact with the tooth surface without saliva or crevicular contamination. Remember, any contamination of the gel by saliva will rapidly deactivate it.
What about the use of lights and lasers to whiten teeth?
The idea behind tooth whitening using lights and lasers is that they are supposed to deliver energy to the gel to accelerate the breakdown of hydrogen peroxide and to release bleaching factors faster. This should then, in theory, whiten teeth faster! In reality this does not happen. Many split arch clinical studies (bleaching done in one mouth with a light used on only one side) show there is absolutely no benefit to be gained from using a light or laser to attempt to enhance teeth whitening. In fact, the use of such devices may contribute to bleaching sensitivity via heat and dehydration.
Is dental bleaching safe?
Is teeth whitening safe? The main bleaching components are hydrogen peroxide and carbamide peroxide. Carbamide peroxide breaks down into hydrogen peroxide and urea. About one third of carbamide peroxide is released as hydrogen peroxide. Urea is a normal body constituent and is of no biological significance in dental bleaching.
Hyrdogen peroxide is found in all body cells as an endogenous metabolite (meaning that it is produced naturally by the body itself). The adult human body produces about 650mg of hydrogen peroxide per day. Using 16% carbamide peroxide in bleaching trays will result in you placing about 6.5mg of peroxide in a set of upper and lower trays.
This means that during cellular metabolism our bodies produce about 100 times more peroxides per day than are placed in standard bleaching trays.
All body cells also contain enzymes which protect against hydrogen peroxide. Hydrogen peroxide is rapidly decomposed by enzymes into water and oxygen. Saliva contains catalase and peroxidases that rapidly break down any hydrogen peroxide released in the mouth during bleaching. Salivary and sulcular fluid peroxidases are capable of destroying 29mg of peroxide every minute.
What are the side effects of teeth whitening?
There are two commonly reported side effects of teeth whitening: teeth sensitivity and gum irritation.
Typically any teeth sensitivity will be mild and last only a day or two after completion of whitening. During Pola whitening we place a great emphasis on reducing tooth sensitivity. It is important to ensure that your teeth are not excessively sensitive to cold drinks or foods prior to beginning whitening. If they are, it is likely that this sensitivity will worsen during the whitening process. If this is the case we will work to eliminate any tooth sensitivity prior to you starting your tooth whitening treatment. Desensitisers will also be used throughout the whitening process to mitigate any sensitivity.
As hard as we may try approximately one in 100 people will be unable to whiten their teeth because of severe sensitivity.
This is uncommon during at home procedures. If it does occur it is usually of minor discomfort and goes away after a night off from bleaching.
Bleaching and amalgam fillings.
Laboratory studies, employing exaggerated conditions, have demonstrated release of very small amounts of mercury from dental amalgam fillings. However, the levels of release are well within the limits of mercury exposure established by the World Health Organisation (WHO) and do not pose a risk to patients. It would always be prudent though to replace any amalgam fillings especially in front teeth with temporary tooth coloured fillings prior to bleaching. This will avoid the very limited risk of producing a green discolouration caused by the corrosion of copper in amalgam fillings.
Professional teeth whitening services in Brisbane, Chermside West
Whitehouse Dental offers an expert teeth whitening service in North Brisbane with proven effectiveness from years of experience. Feel free to get in touch to discuss your particular needs. You can call in for a consultation or feel free to fire us a quick question via phone or via our web enquiry form opposite.