What are the different types of whitening treatments available on the market?

This can be broadly divided into over the counter (OTC) and dentist administered teeth whitening. There are two types of dentist administered teeth whitening- take home or in office teeth whitening. There are many brands available in the market each with its pros and cons.

Can you explain what each of them involves? - What is the procedure? - How long does each treatment take? How many sessions are required? How long does each session take?

The least expensive whitening treatment are teeth whitening toothpaste. It mechanically removes external surface stains and is not as effective, but may be used to maintain professionally whitened teeth. Other OTC products, such as tooth whitening strips, paint-on products and the cheaper boil-and-bite trays use a low concentration of a peroxide-based whitener with limited effectiveness. Over the counter or internet based “custom fitting trays” generally use heat and self moulding to adjust the trays. These trays do not fit as accurately as dentist made custom trays. Poorly fitting trays may cause uneven whitening of the teeth with poor contact of the gel, gel leakage causing irritation to the gums and swallowing of the whitening gel.

For dentist supervised take home bleaching, dental impressions of the mouth are taken. This creates a personalized dental mould and a customized bleaching tray is fabricated in the laboratory. This precise manufacturing process takes about a week. The patient then collects the custom trays and personally taught how to apply the whitening gel. This gel is usually carbamide peroxide based which then breaks down in a controlled manner into urea and hydrogen peroxide. This gel is applied to the bleaching trays and worn daily for an hour or two. The entire process takes about two weeks whereby the teeth will gradually lighten. The bleaching gel does not erode tooth enamel provided that the product used are well researched on.

The in-office procedures are the most costly of all methods of tooth whitening. The first documented attempt at in clinic whitening is attributed to Abbott who in 1918 determined that high intensity light would elevate temperature and increase the efficiency. This involves teeth whitening in the dental clinic. After the gums, cheeks and other soft tissue are isolated and protected, a hydrogen peroxide based bleaching gel is applied to the teeth. A laser or light source is used to accelerate the whitening process. The big advantage of this method of tooth whitening is the immediate result and dramatic improvement in about two hours. However, it is very important to have an initial consultation with the dentist as not all teeth can be whitened and precautions have to be taken for certain cases.

What cases are ideal for teeth whitening?

It is to be expected that with age the shade of a person's teeth will darken. With age the thickness of a tooth's enamel will usually become thinner, thus revealing more of the (darker) dentin that lies underneath. Teeth which are yellow due to ageing resolve favourable with teeth whitening.

Are there people who shouldn't undergo teeth whitening at all?

Dental restorations such as fillings, crowns, bridges and dentures cannot be whitened. Only natural tooth structure can be bleached. After teeth whitening, the dental fillings, crowns or dentures may need to be changed to match the lighter teeth color.

A dark tooth may be due to the dead nerve within the tooth. Such tooth must be treated with root canal treatment first to eliminate the infection prior to tooth whitening. The process of bleaching is also different for a dead tooth. Decayed teeth or leaky fillings must be properly restored with dental fillings. Applying bleaching gel to such teeth with exposure to the tooth nerve may cause extreme sensitivity and may even be harmful to the nerve of the tooth. While tetracycline stains itself is not a contraindication, success is not as predictable. Tetracycline stains can range from yellow brown (mild) to dark grey. Stains that present in bands are more difficult to treat than homogenous discoloration.

Any anaesthesia involved?

No injections/ local anasthetic are needed.

How long do the results last for each type of treatment?

The effects of whitening can last up to three years. However, this will vary from person to person. Surface stains on the teeth would start to appear due to poor oral hygiene (calculus), smoking, drinking coffee, tea, red wine etc. This can be minimized by scaling and polishing at least once in six months after the teeth whitening. A touch up may be needed after a few years.

How much does each type of treatment cost?

The treatment cost ranges widely according to the type of products used, the time spent and the experience of the dentist. Take home teeth whitening system cost less than in clinic laser/light activated teeth whitening.

What are the side effects for each of these types of whitening treatments?

Some transient tooth and gum sensitivity can occur, especially if one already has gum recession or experiences sensitivity when taking cold foods or drinks. Chairside light activated tooth whitening is recommended for such patients as the exposed dentin can be covered prior to applying the bleaching gel. The dentist can also control the exposure and timing of the procedure to reduce sensitivity. The sensitivity is usually temporary and should disappear after a few days.

How white can anyone's teeth get? How many shades whiter?

Tooth whitening can be a highly effective way of lightening the natural colour of your teeth without removing any of the tooth surface. Dentist administered teeth whitening is said to make teeth up to five or six shades lighter. Success would also depend on the types of stains present. Please consult with the dentist to determine if you are suitable.