All about Teeth Whitening

This is the most sought after procedure and certainly most researched on popular search engines such as Google amongst other dental procedures. It is certainly the most cost effective and conservative dental treatment one can get done to improve or enhance one’s smile. However as easy it may be proclaimed to be it’s certainly not without risks.

Let me discuss in brief the two different options available for teeth whitening-

-Self-administered
-Professionally administered

Self administered options have ranged from whitening toothpastes to in home application of the bleaching in custom dental trays fabricated by the dental laboratory. There are numerous other products such as whitening gels, chewing gums, paint on films (varnish), strips etc available over the counter. In this day and age there is lot of marketing hype about the ease with which desired results can be achieved within an hour in a non dental setting such as shopping mall kiosks, spa’s, salons etc.

Professionally administered options include in chair whitening and take home customised kits under the supervision of qualified dental professionals. The methods of in chair whitening procedures can be heat/light/ laser/ chemically activated procedures.

Points to consider prior to undertaking a whitening procedure-

  • Nature of discoloration

This can vary from simple external staining from excessive consumption of coloured foods and drinks such as tea, coffee, red wine, curries etc, lifestyle such as smoking, beetle nut, tobacco chewing (frequency and duration) to staining as a result of excessive fluoride in drinking water leading to dental fluorosis, tetracycline stains, non vital root canal treated teeth, stains from dental amalgam (silver) restorations, leaking and defective tooth coloured restorations etc to name a few. The staining of the teeth may also influenced by the frequency and quantity of acidic beverages consumed (fizzy drinks, energy drinks, off the shelf fruit juices as these acidic and lead to erosion of the surface of the teeth- leading to softening of the tooth surface). Exposed root surfaces are resistant to whitening procedures. These factors amongst others do influence the outcome of the whitening procedure.

  • Safety concerns

The aspect of different chemicals being used in different concentrations does bring to the forefront the safety aspect of the whitening products as there has been a lot of marketing and advertising of different products and their efficacy over each other. To name a few oxidising agents such as hydrogen peroxide, carbamide peroxide, sodium perborate, calcium peroxide, and chlorine dioxide have been used in different concentrations as teeth whitening products.One must understand the underlying chemical reaction initiated by these different products is basically the same i.e oxidation. The active agent in carbamide peroxide is hydrogen peroxide. 10% carbamide peroxide yields 3.5% hydrogen peroxide on decomposing. The whitening products with chlorine dioxide have a low pH and as a result can lead to tooth etching (removal of surface minerals leading to a rough surface).

There are numerous concerns regarding the safety of these whitening products especially the over the counter products. Australian Dental association has provide a guideline for the maximum concentration of hydrogen peroxide in self administered whitening products to be a maximum of 6%, carbamide peroxide containing whitening products to have a maximum of 18%.

In office procedures utilize active hydrogen peroxide in concentrations of 15- 38%. Only a suitably trained dental professional can administer these after a detailed evaluation of the nature of discolouration/ stains. These concentrations are specifically used after complete isolation of the teeth from the surrounding soft tissues.

Whitening products with more than 10% hydrogen peroxide coming in contact with the gingival tissues (gums) can lead to gingival irritation, tissue damage and a burning sensation. (100% proof Hydrogen peroxide is used in jet packs as a propellant)

  • Sensitivity Concerns

Teeth whitening procedures can lead to short term sensitivity on the teeth. This can be mild to moderate in the initial stages of the bleaching process.People with sensitive teeth can have their teeth whitened and their treatment may include administration of analgesics, such as Nurofen, Panadol, etc and use of desensitising (Potassium Nitrate)/ re-mineralising (tooth mousse) agents both before and after the bleaching process in the dental office. This may be followed by a course of analgesics, application of the desensitising products in the form of a gel, toothpaste as well as home application of re-mineralising agents. Other measures may include changing the whitening product application procedure, shorter application times, milder concentration of the whitening products etc. In certain cases whitening may not be an option considering the post treatment sensitivity.

  • Other concerns

These relate to the difference in colour of the whitened teeth in comparison to existing dental restorations (fillings, crowns, inlay onlays etc), prosthesis (partial, complete dentures, etc). These may need to be replaced after the whitening procedure as the colour of the existing restorations and prosthesis would not match the whitened teeth.Teeth with internal stains as a result of decay, dental amalgam, non-vital teeth, endodontically treated teeth would not respond to the external teeth whitening procedures. Endodontically treated teeth would need internal whitening procedure also referred to as walking bleach. They also tend to discolour again over a period of time. Other factors responsible for the discoloration of the endodontically treated teeth would be the dental materials used to complete the treatment. Materials such as AH 26 commonly used as a sealant does stain the tooth from the inside.

Teeth stained as a result of the antibiotic tetracycline administered during teeth development, dental fluorosis do not respond to whitening procedures as well as teeth with extrinsic stains.

Teeth with hypo-mineralization spots may become less noticeable but may need other treatments like tooth abrasion, bonding to achieve the desired results.

Teeth with tetracycline stains may need whitening treatment from a couple of months to a year.

Other considerations may include persons with TMD (temporomandibular joint dysfunctions) can have their symptoms exaggerated as a result of using the bleaching trays at home overnight. Allergies to the bleaching materials, trays may result in adverse effects.

Light/ laser/ heat activated whitening procedures do dehydrate the teeth leading to an increased whitening of the teeth, which reverses in time as the teeth get rehydrated.

  • Number of visits

To achieve the desired whitening results it may require 1-6 visits to the dental office. On an average it takes 3 visits and may include top up whitening kit for home application by the patient.

  • Results

Most often asked question is low long do the results last- the simple answer is that its variable. It depends on the diet, lifestyle of the person and varies from one to the other.

Summary
A thorough dental evaluation as to the current status of the teeth, restorations, prosthesis, and nature of stains is absolutely critical to achieve the desired results. The modality of whitening treatment does not influence the final result. Take home kits and the in-office whitening systems do achieve the same result in time. The difference would be the time involved to achieve the desired results, diet restrictions one has to comply with when using the in home whitening kits compared to the in-office whitening systems. Best results are achieved with a combination of both. Your dentist can provide you with an accurate assessment of the possible outcomes only after a thorough evaluation of your dental status and this is absolutely critical for you to understand prior to undertaking any whitening procedure.

Dr Rakesh Gulia
BDS
Art De Dente
Level 17, 190 Queen St
Melbourne 3000

References-
-American dental association Tooth Whitening/ Bleaching: Treatment considerations for Dentists and their patients. September 2009 revise in November 2010.
-ACCC Competetion and Consumer Act 2010.

 

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