Teeth whitening in Rotherham, checked before it starts

A peroxide gel breaks down on the tooth and releases oxygen, which passes into the enamel and lightens the colour from inside it. Nothing is scraped, drilled or covered over, which is what makes whitening the gentlest thing on this whole section of the site.

It is gradual by design. The gel a dentist can supply is stronger than anything sold to the public, and it still works over two to four weeks rather than in an afternoon, because that is what lets it lift stain without damaging the tooth.

Two reasons, and the tray is the bigger one. A kit tray is a generic shape, so gel leaks out of it: into your mouth, where it irritates the gum, and away from the tooth, where saliva dilutes what is left. A tray made from an impression of your own teeth holds the gel against the tooth and nowhere else.

The gel is the second reason. Anything sold over the counter is limited by law to a concentration low enough to be sold unsupervised, which is why shop kits do comparatively little.

What you are handed here is custom trays, a case for them, written instructions, and a set of syringes in increasing strengths so the first few days are the mildest. Bring the trays to your annual check-up and they get looked over.

That depends on the colour they are now, what caused the discolouration, how dense the staining is, and what dental work you already have. Some causes of discolouration lift readily and some barely move.

Which is why the shades that are realistic for your teeth get shown to you at the consultation, against your own teeth, before you decide anything. A number promised in advance would be a guess.

Cold sensitivity during whitening is common and it is usually temporary, settling within a couple of days of stopping. There are four things that help, in roughly this order: wear the trays for a shorter period, take a day or two off, use a toothpaste for sensitive teeth, or move to a lower concentration of gel.

Mild gum irritation happens too, and when it does it is almost always the fit of the tray rather than the gel itself. That is fixable, so tell us rather than pushing on.

If either carries on after you have finished, get in touch.

Done properly, the effect is thought to last up to about three years, and it varies a great deal from person to person because it is mostly about what you put in front of your teeth afterwards.

In practice: somebody who smokes and eats a lot of staining food is looking at a top-up gel every three or four months. Somebody who does neither may go six months, or a year, or longer. You keep the trays either way, so a top-up is a few nights at home rather than a new course of treatment.

Less of what stains, mostly: tea, coffee, red wine, and smoking above all. Where you are having a staining drink anyway, a straw keeps it off the front teeth, which sounds fussy and works.

Then the ordinary things. Brush twice a day, clean between the teeth once a day, and use the top-up gel when the shade starts to drift rather than waiting until it has gone.