Tooth whitening is generally considered safe - There are however some risks associated with bleaching that a lot of people aren’t aware of –

Like the fact that over half the folks who use over-the-counter peroxide whiteners experience some degree of gum irritation because of contact with the gel in the "One Size Fits All whitening trays.

Over half of those who use peroxide whiteners experience some degree of gum irritation resulting from the bleach concentration or from contact with the whitening trays. Such irritation typically lasts up to several days, dissipating after bleaching has stopped or the peroxide concentration lowered.

Next up is Tooth Sensitivity. Bleaching can cause a temporary increase in sensitivity to temperature, pressure and touch. Now this happens most often with in-office whitening, because of the high-concentration bleach used – And the whitening sensitivity usually lasts no longer than a day or two - in some cases it can last for up to a month – So ask about it.

Some dentists recommend a toothpaste containing potassium nitrate for sensitive teeth.

Some individuals experience spontaneous shooting pains ("zingers") down the middle of their front teeth.

Individuals at greatest risk for whitening sensitivity are those with gum recession, significant cracks in their teeth or leakage resulting from faulty restorations. It has also been reported that redheads, including those with no other risk factors, are at particular risk for tooth sensitivity and zingers.

Finally – And a lot of folks that go for over-the-counter whiteners miss this risk – It’s called Technicolor Teeth.

This happens because Restorations like bonding, crowns or veneers aren’t affected by bleach so they don’t change while the surrounding teeth are whitened.

In addition to the aforementioned risk factors, a number of caveats should be considered before undergoing teeth whitening:

Excessive bleaching can result in unnaturally white teeth.

Whitening results are not fully seen until approximately two weeks after bleaching. This is an important consideration if you are about to have ceramic restorations and want to be sure the color matches that of your newly bleached teeth.

If cosmetic bonding, porcelain veneers or other restorations are part of your treatment plan, they should not be placed until a minimum of two weeks following bleaching to ensure proper adhesive bonding, function and shade matching.

To avoid the Technicolor effect, tooth-colored restorations will likely need replacement after bleaching.

Recessed gums often reveal their yellowish root surfaces at the gum line. That yellow color has proven difficult to bleach.

Pregnant or nursing women are advised to avoid teeth whitening. The potential impact of swallowed bleach on the fetus or baby is not yet known.