Clearly some home and salon products are a lot stronger than 6%, and many people have used them with very few problems with toxicity or tooth damage reported - though the EU SCCP notes that more clinical studies, especially long-term studies, are needed. However, we’d still recommend you try one of the milder products at home. Try to avoid bleach contact with gums as much as possible, and avoid swallowing the bleach. There is some concern, though no conclusive evidence, that peroxides may cause oral cancer, though it's more likely in people already at risk - smokers and those who abuse alcohol.
Excessive strength or excessive bleaching attempts can damage enamel, as can overly acidic products. You may end up with more porous enamel or a bluish tinge.
Your dentist can also provide home bleaching kits, either as a stand alone bleaching process or to supplement in-office power bleaching. These are likely to be more expensive, simply because the dentist will have made custom-fitted trays, though you can be reassured the strength of the product will be appropriate for you.
After the original version of this article was published in 2011, the ACCC recalled in-home products containing more than 6% hydrogen peroxide. New regulations restricting the sale of kits containing more than 6% hydrogen peroxide come into force on 1 May 1 2013. However, dentists may still sell kits exceeding this level for in-home use, based on their professional judgement.
If the tray fits…
The fit of the trays is an important aspect of this sort of whitening. If you’re leaving them on for a long time (30 minutes or so), they need to be comfortable, and not cause gagging or excessive salivation. And the closer they fit, the less bleaching product you need to use. Excessive bleach can ooze out, and while not toxic in small amounts can taste unpleasant and may damage soft tissues.
Some DIY kits involve you making impressions of your teeth, and sending them back to the distributor, who’ll then make and post out a set of custom-fitted trays for you, much like those a dentist would make. They’re a little more expensive, but you can use them for many years.
Pre-filled trays promise the convenience of not having to muck around with tubes of bleaching gel and so on, but because they’re one-size-fits-most, there needs to be a lot of gel in there to make sure teeth surfaces are contacted . Excess gel oozes out and irritates the gums. And you might not be among the ‘most’, in which case it could be uncomfortable, ineffective and messy.
If the idea of mucking around with gels and trays doesn’t appeal, you might prefer adhesive bleaching strips which you stick on your teeth. They’re impregnated with bleach, and once you get the hang of it, can be applied with little fuss, although sensitivity is still a potential problem.
The main disadvantage of strips is that they only bleach the front six or so teeth, and they don’t perfectly fit the teeth, meaning some gaps may be left.
If you’re going to go down the home bleaching path:
- Before buying a DIY kit, visit your dentist for a check up and clean - you want to be sure your teeth are in good condition before you start bleaching.
- Work on one set of teeth (top or bottom) at a time. You’ll notice the whitening effect more if you have a point of comparison and wearing one tray is more comfortable than wearing two.
- Choose products from reputable Australian or US suppliers . Don’t be tempted to save a few dollars buying unreliable products subject to poor hygiene and quality control. Also, there are plenty of scam companies out there, so check the credentials of the company first.
- Start with a mild product before going stronger.
- Be prepared for increased sensitivity. Using the product less often will help, though the whole process will take longer. A sensitive tooth paste and/or Tooth Mousse (see Tooth Mousse: is there anything it can’t do? below) can reduce sensitivity.
- Don’t over bleach – don’t use more product (it won’t help), leave it on too long or do it too often. And you only really need to bleach the front surface of your teeth.
Tooth mousse: is there anything it can’t do?
Developed initially by a team of dentists and scientists at the University of Melbourne, this great Aussie innovation has taken the dental world by storm. Tooth Mousse contains calcium and phosphate derived from milk protein (casein), and it remineralises the enamel surface of the tooth, preventing and reversing surface damage.
It’s recommended for tooth erosion, early decay, fluorosis, lesions due to orthodontic treatment and tooth sensitivity – including post-bleaching sensitivity. By strengthening the enamel, it also protects against erosion and caries, and can be used pre-whitening to prevent sensitivity. Applied after fluoride treatment, it enhances fluoride penetration to further protect teeth. Apart from relieving post-bleaching sensitivity, it also helps keep your teeth white longer by resisting staining . And while the company doesn’t make any claims about whitening, anecdotal reports indicate that with regular use it slowly whitens unbleached teeth.
You can buy some online (search for GC Tooth Mousse) or from your dentist, for around $20-25 a tube. Chewing gum products are also available.