Smart Consumer: Go the white way about making those teeth glow
How much for a Hollywood smile? I'm not talking about straight or healthy teeth but a mouthful of pearly whites so bright they could stop traffic.
Some celebrities do tend to go over the top when it comes to the dazzle factor, but even if you just want to go a little lighter, you'll still have to put bleach on your teeth.
So how much is too much?
Tom Feeney, the Irish Dental Association representative on the Council of European Dentists, says that to be effective a product has to contain over 3pc hydrogen peroxide.
And a new Cosmetics Regulation that will be voted on in the European Parliament next month will prohibit products containing more than 6pc, as levels over this are considered unsafe for consumer use.
Dublin-based dentist Feeney believes that such regulation is long overdue, especially as he warns that some teeth whitening products easily available online contain very high levels of the chemical.
In fact, home teeth-whitening products such as whitening strips can contain 6.5pc, 10pc or 14pc of hydrogen peroxide and Feeney says that due to a lack of coherency in current legislation some dentists in other European countries use products containing up to 35pc bleach. And that would burn the gums off you.
Aside from burning gums, risks include irritation of the lining of the mouth and the bleach can be harmful to oral tissue if it is already injured.
Feeney cites a patient who visited him recently for tooth whitening, but after an examination he found she had an ulcerative condition on the tongue. Using a teeth-whitening product could have caused further damage.
And if you are both a heavy smoker and drinker, tooth whitening could damage your already fragile tissue.
Tooth colour is genetically determined, just like hair colour, so tooth whitening might not work for some.
And while smoke or coffee stains are most responsive, it doesn't work well on crowns, veneers or fillings. It is also advised that pregnant women and children stay away from the bleaching trays. But in case you're worried, there is no evidence that it damages enamel.
But all these variables mean it's important to get a check-up first.
"The first thing you should do", explains Feeney, "is to visit your dentist for an oral exam including a full dental history. If the stains are superficial a clean and polish might be sufficient, but if the discolouration is intrinsic in the tooth then your dentist can help you decide what method would suit you best."
The Irish Dental Association has expressed concern about unsupervised tooth whitening and the risks associated with it are something the General Dental Council in the UK takes very seriously.
In March this year, following hundreds of complaints, they levied fines on the Director of Style Smile Clinics for four offences, including practicing dentistry (ie, teeth whitening), while not registered as a dentist.
While there has been no action like that here, there are non-dentists offering the service and plenty of teeth whitening products are easily available online and in some pharmacies.
The Americans may be mad about it, but it seems we're catching on.
Lightening your teeth and improving you appearance can be wonderful. And it can be perfectly safe, so long as you go about it with a bit of sense.
Buying over-the-counter products is much cheaper, but may be false economy if it doesn't work or the product does some damage. So choose wisely and well.