Smile on whitening

The result depends on the original tooth colour, the type of stain, and whether the discolouration is on the surface or within the tooth structure.

This question usually means wanting a brighter smile through tooth whitening. Whitening gels commonly contain hydrogen peroxide or carbamide peroxide, which penetrate enamel and dentine and break down coloured compounds.

Coffee, tea, tobacco, and plaque can cause surface staining, while ageing, dental trauma, some medicines, and changes in dentine can produce deeper discolouration that may respond differently.

Start with an examination and cleaning so decay, leaking fillings, gum inflammation, and exposed root surfaces are identified before whitening. A dentist may then provide custom trays for home use or apply whitening gel in the clinic, following the product instructions and planned contact time.

Use a soft toothbrush, clean between the teeth, and limit strongly staining foods and drinks while the whitening plan is underway. Do not place whitening gel on the gums or use it over untreated dental disease.

Arrange a dental examination before whitening if you have tooth pain, untreated decay, cracked enamel, bleeding or swollen gums, or sensitivity that is already present. These problems can make whitening uncomfortable and may need treatment first.

Contact the dentist if whitening causes persistent pain, marked gum irritation, or a sharp response to cold. A dentist can check whether the gel concentration, tray fit, exposed dentine, or another condition is contributing.

Ask which teeth are suitable for whitening, whether any cavities or gum problems need treatment first, and whether existing restorations will remain a different colour. Ask how the trays or in-clinic gel will be used and what to do if sensitivity develops.

Also ask whether the colour change is likely to respond to peroxide whitening or whether bonding, a crown, or a veneer would be considered for a non-whitening tooth.