Tooth discolouration
Teeth Whitening
Lightening the colour of natural teeth with a peroxide gel, once the reason they have darkened has actually been established.
Find the cause first
Teeth darken for several different reasons, and only some of them respond to whitening. Surface staining from coffee, tea, red wine, curry and tobacco sits on the outside and often comes off with a cleaning rather than needing whitening at all. Age related darkening comes from enamel thinning and the yellower dentine underneath showing through more, which whitening can lighten. A single tooth that has gone grey after a knock or a root canal has darkened from the inside and needs a different approach.
Staining from tetracycline taken in childhood, and white or brown mottling from fluorosis, sit within the structure of the tooth and respond poorly or unpredictably. This is why an examination before whitening is not a formality. It establishes what is actually causing the colour, and it checks for decay, cracks, leaking fillings and gum disease, all of which should be dealt with before any gel goes near them.
How whitening works
The active ingredient is hydrogen peroxide or carbamide peroxide, which breaks down and lifts pigment out of the tooth. Stronger gel applied in the office works faster per session. Weaker gel worn in a custom made tray at home works more slowly over a longer period. Both rely on the same chemistry, and both need the gum kept off the gel, which is what the custom tray or the in office barrier is for.
Existing fillings, crowns, veneers and bridges do not change colour. If a front tooth carries a restoration that was matched to the current shade, whitening the teeth around it will leave it looking darker, and it may need replacing afterwards to match. That is worth knowing before starting rather than after, because it changes the cost of the whole exercise.
Visits, Recovery and When to Call
Visits and timing
Whitening usually begins with an examination and a cleaning. Home tray whitening then needs an appointment to take impressions and fit the trays, followed by a period of wearing them. In office whitening is done in appointments at the practice. How long any of it takes varies from person to person.
Afterwards
Sensitivity to cold during and shortly after whitening is common and normally settles within a few days of stopping. A toothpaste for sensitive teeth helps. Gums can be sore if gel has contacted them. Avoid strongly staining food and drink while whitening, since teeth pick up colour more readily during that period.
Call sooner if
Sensitivity becomes severe rather than mild, gums are burnt or ulcerated, or one tooth reacts sharply and differently from the others, which can mean a crack or exposed dentine that was not obvious. Stop and get it looked at rather than pushing through.
What whitening cannot do
Results differ between people and between teeth in the same mouth, because the starting colour, the cause of the discolouration, the thickness of the enamel and the shade of the dentine underneath all differ. No dentist can tell you in advance exactly what shade you will end at. Whitening also does not last indefinitely, since the same habits that stained the teeth in the first place go on doing it.
Keep reading
Questions About Teeth Whitening?
Describe the problem on the phone. That conversation is usually enough to work out the first appointment. Mandarin, Taiwanese, English and Japanese are spoken.