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Re-whitening can restore teeth to their original lustre
Now that your cavities are under control, your incisors are straightened and your root canal crisis has passed, just how stained and yellow are those teeth? In a recent North American poll, queries about teeth whitening topped the list of questions asked of dentists by their patients.
"I prefer to call it re-whitening," says Dr. Ed Philips who, right off the top, wants to correct the perception that stained or yellow teeth are somehow whitened by the addition of white colouring in the process that many dentists now offer.
They’re not.
In the dental office whitening process and in the home-whitening kits which proliferate on drugstore shelves, teeth are only "de-stained" and "un-yellowed." In other words, their colour is only brought back to what the colour of the teeth might have been, say, 20 years ago.
Whiter teeth are part of the social evolution of the mouth, says Philips, who runs Toronto’s Studio for Aesthetic Dentistry.
"Historically, during caveman times, teeth were weapons used to eat and to chase someone away. Strong teeth and a scary, gap- toothed, awful smile were good things."
Today, Philips adds, we ask exactly the opposite of the smile.
"Today, it means ‘I’m friendly. Come closer to me.’ Whiter teeth appear healthier and cleaner and that’s more socially acceptable."
It’s true that some people have almost pure white teeth, but when you look at a porcelain palette (the array of colours the dentist holds against your tooth to match the filling to the right natural shade) there’s a wide range of natural colours and many of them have a slight yellowish tinge.
The "Chiclets" smile? False, jarring and not the goal in the whitening process, experts say.
Like crow’s feet and morning stiffness, darker teeth are a product of aging but are accelerated by coffee, tea, red wine, tobacco – even eating lots of curry or beets.
"These are outside stains," says Dr Kenneth Montague, a Toronto dentist. "They enter the tooth enamel on a surface level only."
Montague explains that the tooth’s outer enamel is composed of little pores and that these stains go into the micro pores.
"These stains are hard to get out with a toothbrush but respond well to the tooth-whitening products," Montague adds.
But what exactly are these products? How much do they cost? And how safe are they to use?
Dentist-supervised bleaching is the method most preferred by the Ontario Dental Association. With it, an impression is made of your upper and lower teeth. Then customized trays that fit around the teeth are made. You take the trays home, squeeze in some bleaching material that your dentist has dispensed, then stick the tray to either your upper or lower teeth in much the same way kids make orange- peel teeth or put in a hockey mouthguard.
Because it sticks on pretty snugly, you can sleep on it and speed up the whitening process. It generally works after doing it about 10 nights, but not necessarily 10 nights in a row.
Montague says the process costs under $500.
Many people prefer the daytime method. Also under a dentist’s care, you wear your trays while you’re awake 30 minutes each day. The only setback is you can’t talk, eat or smoke during that time, which is why some people still choose the overnight versions. The price is the same.
Montague says the bleaching process uses an agent like a peroxide that leeches into the teeth. It lightens up, not unlike Javex, but using it effectively is a control issue.
"We don’t condone people using chemicals on their teeth," Montague says.
The chemicals contained in these products have to be powerful enough to do the job but not powerful enough to harm.
Philips explains that the whitening pumps oxygen molecules into the natural pores of the tooth. In doing so, it binds to the artificial colouring that has built up over the years in these pores. The combined oxygen and the yellow pigment join and break down the colour to lighten the teeth a shade or two.
In a survey done of 8,000 dentists in the U.S., 66% of patients reported varying degrees of irritation with bleaching kits although several studies show that tooth whitening is safe when performed properly.
"We are very concerned about the misuse of home-bleaching kits," Montague says.
By home-bleaching kits, he’s referring to the growing number of products available over-the-counter from drug stores. I bought the Natural White 5-Minute tooth whitening system. At less than $15, it was a deal – but dentists say these home whitening kits don’t have the strength that their systems do.
"If you insist on using these, bring them into your dentist and discuss the process. You don’t want it to be harmful," Montague says, adding that some unsupervised home bleaching can burn or irritate gums.
He adds that no whitening treatment can make teeth whiter than their original colour and the process won’t work on crowns or teeth that are darkened as a result of illness or drugs. (Some antibiotics, taken in childhood, can darken teeth right through, and not just on the surface.)
Tooth whitening isn’t a quick answer. Stains return and the process has to be repeated.
Nonetheless, Montague says, "I’m a believer. Twenty years ago, nobody talked about it. A decade ago it was a mumble. Today, it’s a roar."
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