Not everyone’s teeth are suitable for whitening. If the teeth and gums are not in healthy condition before whitening, the procedure may cause more harm than good. Even if there is nothing wrong with the teeth there may be other reason why whitening will not work.

The safest way to work out if teeth are suitable for whitening is to see a dentist first. Dentists are the only people trained and qualified to make an accurate assessment of the teeth and gums before whitening.

What should a proper dental assessment include?

A dentist will check for things like enamel thickness, receding gums, existing restorations (e.g. fillings, crowns and veneers), and any other oral diseases or conditions. The cause of discoloration will be assessed, (e.g. diet, ageing, antibiotics etc.) and whether it is on the surface or inside the teeth. A tooth that has been discolored from root canal treatment may be whitened from inside the tooth; this is called non-vital bleaching. Only a qualified dentist is able to carry out these checks and then recommend a suitable whitening treatment.

How does teeth whitening work?

The process of teeth whitening involves oxidising agents such as hydrogen peroxide which alter the tooth surface to change the way it reflects light. When used repeatedly and in inappropriate dosages for long periods of time, it may cause irreparable damage to teeth.

There are usually two methods of application:

• A professionally made tray used at home to apply the whitening agent; this may involve applying the agent for a short period of time regularly over 1-2 weeks
• Application of the whitening agent by a dentist in the dental chair; this may involve one or two visits which can take up to over an hour and sometimes involves heat or light to accelerate the whitening process

A dentist will advise which method is most suitable. The agent used in the dental chair is usually of a higher concentration and may potentially cause more tooth sensitivity and other side effects.

What will be felt during and after the procedure?

Some people notice a ‘bubbly’ sensation on the surface of their teeth, or periods of sharp pain inside the tooth while the bleaching agent is in contact with their teeth. Others notice an achy feeling in their teeth for a few days following the treatment and temporarily heightened sensitivity when biting into certain foods and consuming cold beverages. Any painful; sensations should be reported to a dentist.

What can go wrong?

For many people teeth whitening poses no risk if done correctly. However, there are a number of potential side effects from teeth whitening. Some will be temporary but some can be permanent; if the teeth react badly to the treatment they may never be able to go back to the way they were. Some of the effects of teeth whitening can include:

• Heightened tooth sensitivity
• Alteration of the enamel surface (the effect of hydrogen peroxide on tooth enamel is irreversible)
• Reduced strength of resin-based filling materials
• Damaged and inflamed gums
• Chemical burns
• Blistering of mouth and gum tissues
• Uneven colored teeth (existing fillings, crowns and veneers will not change color)
• Severe irritation or burns if the bleaching agent is exposed to the skin or eyes
• Irritation to the esophagus and stomach if the bleaching agent is swallowed, which can result in bleeding

It is important to know how concentrated the whitening agent is before starting the procedure as the concentrations can range from 3% to 35%!

What results can be expected?

Depending on the cause of the discoloration results can range from impressive to disappointing so it’s important to understand what can reasonably be achieved before going ahead with any whitening procedure. The reality is that most people will achieve a one or two shades change but many will see no change at all. What works for one person will not work for another.  Again, a dentist’s advice is needed on this.

How to reduce staining:

Extrinsic stains are superficial stains found on the surface of the tooth, which are caused by dental plaque, tars (in tobacco), tannin, colored foods and frequent use of certain mouthwashes. Common foods and beverages that stain teeth include:

• Herbal and black tea
• Coffee
• Red wine
• Spicy foods like curries

Smoking cigarettes also causes stains on teeth, which can be extremely difficult to remove. Most extrinsic stains on the tooth’s surface can be removed by a dentist performing a professional scale and clean.

Teeth Whitening Checklist

• First try other ways to whiten teeth without using a chemical treatment, like having a professional scale and clean by a dentist and maintaining good oral hygiene and diet habits
• Consult a dentist to assess the suitability for teeth whitening
• Have a dentist recommend a course of action or specific treatment
• Make sure the treatment method, side effects and potential results are fully understood before applying any whitening agent at home or in the dental chair.

*By Dr James Fernando, ADAVB Oral Health Committee