Cosmetic dentistry has become BIG of recent years and looks set to grow in the forseeable future according to indicators in the USA. Programes on TV like ‘The Swan’ and ‘Ten Years Younger’ just show how cosmetic dentistry can literally transform a persons self image and improve confidence as well improving ones appearance. Bleaching, in particular, is one branch of cosmetic dentistry that has become popular. It is within the means of most individuals to get this done. This article is aimed at discussing different ways of trying to lighten teeth and the two main ways that practices bleach teeth. We also outline why we feel that Take Home bleaching in custom trays represents excellent value for money over the alternative In Office bleaching.
Generally speaking, when one thinks of whitening teeth, there are three possible ways to go about this. The first method is to purchase over the counter whitening toothpastes. Then there the two types of bleaching one can get done at the dentists – Take home bleaching and In-office bleaching.
Whitening toothpastes are effective at removing stains over the teeth due to their abrasivity. They vary in abrasivity, but the majority are more abrasive than normal everyday toothpastes. This is how they whiten teeth. They will not alter the intrinsic colour of the teeth and hence will not be more effective than the dentist directed bleaching procedures. Incidentally, whitening strips did enjoy a brief surge in popularity, but people found that they were difficult to place over mal-aligned teeth and only the front teeth could be bleached (from canine to canine). However, the strips did work.
This brings us to the two methods of dentist directed bleaching – Take Home Bleaching and In-Office Bleaching. Both methods work well . Bleaching works by the oxygen released by hydrogen peroxide (the active ingredient of bleach) breaking down the conjugated bonds in protein chains. This increases the absorption of colour wavelengths by teeth resulting in the reflection of little colour (i.e. a lightening effect). Most people have teeth that will respond positively to bleaching. Bleaching works well in those with yellowing teeth without any systemic or developmental cause, mild fluorosis staining, mild tooth darkening due to trauma or mild tetracycline staining. Patients with deeply stained teeth (e.g. dark tetracycline stains) will be more resistant to bleaching and an improvement in colour may take up to six months using at home bleaching trays.
At Absolute Dental Care, we whiten teeth using using ‘Take Home Bleaching’. Studies vary as to how long the bleaching effect lasts,but you should have results lasting 3-7 years. There has been a study to show relapse rate of 26% at 18 months. Basically, close fitting trays are made to fit over your teeth. You place the bleaching material (10 – 16% carbamide peroxide which releases the hydrogen peroxide) overnight for a period of two weeks. One can actually get away with wearing the bleaching trays for only 2-3 hours as the residual activity at 2 hours is only about 30% and only 10% at 3 hours. This has proved very successful within our practice with the majority of patients going several shades lighter. The technique is very safe with no decrease in the hardness of the tooth structure and no harmful effects on the nerves within the tooth. There are side effects to the bleaching process. However, all side effects disappear within a day or two of completing the bleaching. The most common side effect is tooth sensitivity. It occurs in 18-78% of patients. Others include mild gum irritation, splotchy appearance of the teeth in the early stages of bleaching, the taste of the bleaching agent and mild throat soreness. There are many ways to combat the sensitivity and several of the bleaching agents contain Potassium Nitrate which is a desensitising agent.
In Office Bleaching is the other way of bleaching teeth. It involves using a much higher concentration of hydrogen peroxide (25-28%, depending on system used). This is painted over the teeth and a light source shone over the teeth. Ther are a few systems that do not utalise a light. Because the material is irritating to the gums, the gums are protected with a ‘rubber dam’ or proetective resin. You sit with the light shining on the teeth for about an hour. The process may then be repeated. Most patients have 2 appointments like this. We do not use this technique of bleaching at Absolute Dental Care for several reasons. Firstly, because there is much clinical time required, the technique is invariably more expensive. Secondly, the concentration on hydrogen peroxide is higher. This means more sensitivity and more gum irritation if any seeps through the protective barrier. Some of the lights generate heat also, so all-in-all, it is quite a harsh procedure to subject ones teeth to. Thirdly, the relapse rate is higher than Take Home tray bleaching – about 41% at one year. We don’t consider this good value for money. Fourthly, the dental literature is not convincing on whether the light actually does anything. There are no free radicals to generate. No light is needed for the hydrogen peroxide to work as the critical factors causing lightening of the teeth are the concentration of the bleach and duration of use. We consider the use of the light as unnecesary and just adds to the expense of the procedure. Furthermore, during the In Office bleaching, the teeth dry out significantly. This drying out effect make the teeth look lighter than they actually are and it is only when the teeth rehydrate that the true extent of the lightening effect can be assessed. Most In-Office bleaching procedures have to be supplemented with a short course of Take Home bleach in trays. So the question arises if the whitening one gets from the In Office procedure is due to the In Office part or due to the Take Home part. We will not be introducing In Office bleaching to our practice due to us not being convinced of it representing good value for money for our patients. It as a good option, however, for patients who want an immediate result or who have a busy lifestlye that does not allow them to use Take Home Bleaching.
Tags: Bleaching, Cosmetic dentistry, tooth whitening, whitening teeth