Seven questions that come up in almost every whitening consultation, with the short answer first and the longer one for those who want it.
A custom tray does most of the work
A tray made on a model of the patient's own teeth holds the gel where it should be and keeps it off the gums. The concentration matters less than the fit.
Two weeks of nightly wear is the usual course; sensitive patients wear it every other night for four.
What patients ask
Will it damage my enamel?
No. Carbamide and hydrogen peroxide at the concentrations used in dentistry do not remove enamel; the surface looks rougher under a microscope for a few days and recovers.
Why do my teeth hurt during whitening?
The peroxide reaches the pulp through the dentine and irritates it briefly. The sensitivity stops within a day of stopping the gel; a potassium nitrate toothpaste before and during the course reduces it.
Will my crowns and fillings whiten too?
No. Ceramic and composite keep their shade, which is why a restoration in the smile line is sometimes replaced after whitening, never before.
How long does it last?
Between one and three years, depending on coffee, tea, red wine and tobacco. A night or two of tray wear brings the shade back.
Can I whiten with braces on?
Not with fixed braces: the gel cannot reach under the brackets. Aligner patients can use their aligners as trays.
Is in-surgery whitening better?
It is faster. The shade after a month is the same as with trays, and the sensitivity during the session is higher.
What about whitening toothpaste?
It removes surface stain and nothing else. The shade of the tooth itself does not change.
Patients do not want white teeth. They want teeth that look clean.
One more question, the one they do not ask
Whether the shade they have in mind suits their face. A tooth whiter than the whites of the eyes looks wrong on everyone, and a photograph before the course, shown beside one at the end, settles most disagreements.
Answer the sensitivity question before it is asked.
It is the reason most patients stop early, and the reason most who finish are happy.
