Teeth Whitening / Bleaching

Tooth whitening is a bleaching process that lightens discoloration of enamel and dentin.

Tooth bleaching, also known as tooth whitening, is a common procedure in general dentistry but most especially in the field of cosmetic dentistry. Many people consider white teeth to be an attractive feature of a smile. A child's deciduous teeth are generally whiter than the adult teeth that follow. As a person ages the adult teeth often become darker. This darkening is due to changes in the mineral structure of the tooth, as the enamel becomes less porous. Bacterial pigments, foodstuffs and tobacco can also stain teeth. Some medications can also cause teeth stains or a reduction in the brilliance of the enamel.

As white teeth are subconsciously associated with youth, they have become desirable. This has been made more apparent with the spread of American culture worldwide, where an especially white smile is coined a "Hollywood smile". The procedure to bleach teeth uses oxidizing agents such as hydrogen peroxide or carbamide peroxide to lighten the shade of the tooth. The oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and oxidizes interprismatic stain deposits; over a period of time, the dentine layer, lying underneath the enamel, is also bleached. Tooth bleaching will generally last from 2 to 5 years, with variations from factors such as cigarette smoking, and tea and coffee consumption

A typical course of bleaching can produce dramatic improvements in the cosmetic 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 dentine layer. White-spot decalcifications may also be highlighted and become more noticeable. Bleaching is least effective if teeth have white spots, decay or infected gums. It is also least effective when the original tooth color is grayish. Bleaching is most effective with yellow discolored teeth.


Methods

There are many methods to whiten teeth: bleaching strips, bleaching pen, bleaching gel, and natural bleaching. However the most advanced and sought after method of is laser teeth whitening. Most dental practices offer two types of whitening: In- Office bleaching and Home Bleaching utilizing take-home dental bleaching kits.

The first involves applying a high concentration of oxidizing agent for a short period of time, which is the so-called office bleach. This produces quick results but risks chemical burns to the soft tissues. Therefore, 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). 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 up to 35% hydrogen peroxide equivalent.

The second method involves using a thin mouth guard or strip to hold a 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. This is known as take-home or over-the-counter bleaching. This is a slower process but has fewer risks to the soft tissues. The bleaching agent is typically less than 10% hydrogen peroxide equivalent.

Both procedures are based on a bleaching process that uses a peroxide-based bleaching gel of varying strength (3%-30% peroxide). The higher the concentration of peroxide in the gel, the more powerful it is. While a higher concentration gel is more effective at whitening the teeth, it also has greater potential to cause side effects such as sensitivity and damage to the surrounding gum tissue and your lips.

Laser Tooth Whitening

A majority of teeth whitening systems may take weeks before the results show up as compared to when you use laser teeth whitening. When laser teeth whitening is opted for the results are immediately noticeable though there can be a difference in shades of whiteness that results from the laser teeth whitening. In laser assisted tooth whitening, lasers are used to speed up the in-office teeth whitening procedures. A peroxide bleaching solution, applied to the tooth surface, is "activated" by laser energy, which speeds up of the whitening process. All lasers work by delivering energy in the form of light. When used in teeth whitening procedures, the laser acts as a heat source and enhances the effect of tooth bleaching agents.

Laser tooth whitening or in-surgery whitening is a procedure that takes place at the dental practice and uses a light-activated bleaching gel to whiten your teeth. The procedure usually takes  approx 1 -2 hours and produces instant whitening results.  Many dentists recommend that laser whitening should be followed up by professional home whitening.

Prior to carrying out the procedure you would have a consultation with your dentist to make sure that you are suitable for teeth whitening and to explain possible risks and side effects of the procedure. Most dental practices will ask you to sign a teeth whitening consent form to confirm that you have fully understood the procedure and all relevant information.


Before the teeth whitening process is started a dentist or a hygienist will thoroughly clean the teeth, removing any surface stains and tartar. This procedure is commonly referred to scaling and polishing.

The next step will be for the dentist to make a record of the shade/colour of the teeth before the procedure. This is either recorded using a tooth coloured shade guide/chart or by taking a digital photograph of your teeth.

The area is then prepared for the procedure. The bleaching compound usually contains a high concentration of peroxide (15-30%) and so the dentist will usually place some form of protection around the gums so that only the teeth are exposed to the compound. This involves covering the gums with rolls of cotton and a protective gel material that hardens once applied to the gums. A cheek retractor is used to keep the lips and cheeks away from the teeth.

It is very important that your dentist isolates your gums and lips with a protective material in order to avoid any potential damage or burning. Home whitening kits usually have a low concentration of peroxide so that there is less chance of any damage occurring. Recently, high-strength home whitening kits purchased online and from certain stores have attracted media attention with horror stories of people with badly burnt lips and gums. It's for this reason that teeth whitening should always be carried out under the supervision of a dentist.

Eye protection (goggles) is also provided to prevent any damage to the eyes from the laser used or any accidental splashes of the peroxide. 

The whitening gel is then applied to the surface of the teeth and exposed to a light or laser, which activates it. Some systems do not use an activating laser and many dentists argue that the laser doesn’t make any difference to the end result.  During this process if you feel that your lips or gums start to burn then you should let your dentist know immediately. After approximately 15 minutes the gel is removed and the process repeated another 2 times. During the procedure some people may feel sensitivity in their teeth, which are described as short-lived shooting pains.

The dentist will finally wash off the whitening gel and remove any gum protection before evaluating the final result by taking a photograph or using a shade chart. The results are usually quite dramatic and can often be up to 10 shades lighter. A kit for home whitening may also be provided with custom trays and professional whitening gel.

Many patients’ teeth are quite sensitive immediately following this procedure and it is advised to try and avoid hot or cold drinks for a while. Some dentists offer fluoride treatment following teeth whitening to reduce this effect on sensitivity. Your home whitening kit usually contains a solution to reduce tooth sensitivity. Sensitivity rarely lasts more than 48 hours, if symptoms persist for longer than this then contact your dentist.

Professional home whitening kits provide more permanent results over a longer time scale, whereas laser tooth whitening offers immediate results. A combination of the two provides the perfect solution to both immediate and long-term whitening needs.

Professional home whitening kits


To make a professional home whitening kit, your dentist will take a impression (mould) of your teeth using a special dental putty. Your dentist’s technician will then use this to cast a model of your teeth from plaster and make your custom teeth whitening trays from this. Once these trays have been made (usually takes 5-10 days) you use them in combination with professional whitening gel (provided by your dentist) until you are happy with the results. Depending on the teeth whitening system, some trays need to be worn overnight while others for only 1-2 hours a day.




Suitability for whitening and other relevant information:

Many people are not suitable for teeth whitening and a dentist will assess your suitability during a consultation. If you have gum disease or other dental health problems, you may not be suitable. The teeth whitening process does not change the colour of crowns, veneers or fillings so it is important to understand that you may need to change these to match the colour of your whitened teeth.

The extent of whitening achieved varies from individual to individual, and also depends on the type of whitening system used. Some people respond very well to teeth whitening and have dramatically whiter teeth as a result, whereas others may notice very little difference at all. People with heavily stained yellow teeth tend to have more dramatic results than those with slightly discoloured teeth.Your dentist will be able to advise you on the likely results following a consultation.

Side effects of teeth whitening:  Some people experience no pain or sensitivity with their teeth. However, the majority of people will experience some kind of sensitivity either during and/or after the initial treatment. This is usually described by patients as sporadic, sharp shooting pains coming from their teeth. This should settle down after approximately 48 hours though. Your dentist may give you a special gel or mousse to apply to your teeth to help with the sensitivity. It is advisable to avoid hot or cold food and drinks within the first 48 hours of your whitening treatment.


Content provided by www.cosmeticdentistryguide.co.uk

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