Strong, white teeth good for self-esteem, health

Dentist at Lagos University Teaching Hospital (LUTH), Dr. Bimbo Akindele in this interview with GERALDINE AKUTU said the teeth colour is of cosmetic importance and any changes in the structures will lead to alteration in the colour of the teeth.

Is the natural colour of teeth white?
Generally, people can have different shades of teeth. The enamel is translucent, hence the underlying dentine, which is yellow, reflects; so the colour seen is usually light yellow. Primary teeth usually appear whiter than permanent teeth because the enamel, which is the outermost part of the teeth, is less translucent (more opaque). Thus, the yellowish colour of the dentine does not reflect as much as in permanent teeth, which have more translucent enamel

Even in the same individual, the different types of teeth have different shades. For instance, the canine has more bulk of dentine and thus appears more yellowish than the others. Even in a single tooth, the colour varies. The part of the tooth closer to the gum appears more yellowish than the part close to the edge.

Do people really need to whiten their tooth?
If there is a change in colour of the tooth, an individual can seek to change the colour. If it is a cause of concern to the individual, affecting his or her self-esteem. Note that as people get older, their teeth become more yellowish because of increased dentine bulk. The teeth may have absorbed different sources of stains over the years or the enamel is more thinned out.

How can people with stains improve their teeth colour?
Treatment of tooth discolouration depends on the source of discolouration. If it is extrinsic (due to external sources) or if it is intrinsic (internal), things can be done to improve the colour of the teeth. Certain methods are used to treat or whiten teeth.There is scaling and polishing, which can be used to treat extrinsic stains (poor oral hygiene, beverages and tobacco, among others). All these cause stains, which affect the external surfaces of the teeth. Scaling and polishing may make the teeth appear whiter.

There is also etching and abrading, using HCL paste. This is neutralised with sodium bicarbonate. Fluoride gel is applied. Veneer is used for hypoplastic teeth, where there is mild discolouration and where there is associated tooth wear. Crowns is the treatment usually done where discolouration is due to intrinsic source, causing severe discolouration or where there is loss of tooth structure.

Then there is teeth whitening or bleaching, which is a treatment modality involving an oxidative chemical that alters the light-absorbing and/or light-reflecting nature of a material structure, thereby increasing its perception of whiteness. This can be used to treat intrinsic discolouration (for instance mild tetracycline staining, discolouration following a root canal treatment). Bleaching is not done in patients who have dentine hypersensitivity, heavily restored teeth, hypoplastic or severely undermined enamel.

When should people think of whitening their teeth?
Bleaching can be done for a vital tooth or non-vital tooth. It can be done for a vital tooth, if it has moderate tooth discolourations, teeth with no significant structural defect, fluorosis staining, with stains ranging from simple, white, opaque spots to a darker discolouration, discolouration related to the physiological ageing of teeth, improvement of the teeth’s natural colour before the placement of a prosthetic restoration in the adjacent area.

Bleaching in vital tooth is not done for young patient aged under 15-16, due to large pulp volume. It is also not done on teeth with dentine hypersensitivity or teeth with recurring caries. Vital bleaching procedures are performed in the clinic by a dental professional or at home by the patient. In the dental clinic, it is done by using bleaching materials, such as hydrogen peroxide, and use of laser (Argon laser, CO2 laser). Vital bleaching can also be done at home using custom fit tray with 10 percent carbamide peroxide. It is the more commonly used technique because it is easy to perform and is usually less expensive for the patient. Non- vital bleaching is done in the clinic using thermo catalytic, ultraviolet photo oxidation.

What are the advantages and disadvantages of tooth whitening?
The advantages include improved aesthetics and improved self-esteem. The disadvantages include dentine hypersensitivity, which is a commonly observed clinical side effect during or after bleaching of vital teeth, with incidence of up to 50 percent. The sensitivity, usually mild to moderate and transient, often occurs during the early stages of treatment and usually persists for two to three days. Gingival irritation may occur. Treatment may need to be repeated severally.
Discolouration of teeth is always a source of concern for the patient, especially if it occurs in the front tooth or teeth, and it is related to psychological and social concerns. Bleaching might be a very easy solution to some of these patients. However, it should be noted that bleaching could also lead to some side effects.

Are local methods of tooth whitening effective?
Local methods include use of charcoal and certain fruits.
With regards to charcoal, studies have shown that it does not cause tooth whitening, but only act as an abrasive, which helps to remove extrinsic stains. However, this has negative long-term effects, as it can eventually lead to thinning of the enamel, thus eventually causing dentine hypersensitivity. The fruits that are used also contain citric acid, which can also act as a bleaching agent. However, the concentration is not monitored hence may lead to adverse effects.