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Don’t whiten your teeth without reading this Trudie McConnochie Reviewed by Trudie McConnochie

Thanks to social media, there’s been an explosion in demand for teeth-whitening services – including dental services, kiosks and online kits. But these methods can have side-effects – read on to learn more.

In case you hadn’t noticed, teeth whitening is white hot. There is increasing demand for teeth whitening, a trend largely credited to celebrity culture and the popularity of selfies.1 There’s a range of ways you can achieve a glamorous white-toothed smile, but some are more effective than others – and all have potential negative side-effects that you need to consider.3

First up, let’s get clear on what teeth whitening is. As the name suggests, teeth whitening is a procedure where teeth are bleached – usually with the chemicals hydrogen peroxide or carbamide peroxide – to lighten their colour. When a bleaching agent is applied, it penetrates the top layer of the tooth (the enamel) and works on the dentine, the part of the tooth that determines its colour. Here the chemicals react with the discoloured molecules to lighten the tooth.3 Tooth whitening works on extrinsic discolouration only – meaning it targets the tooth surface. This method does not easily whiten intrinsic staining, which is discolouration embedded within the tooth structure itself. Intrinsic staining can be caused by certain antibiotics, medications or trauma to a tooth such as an injury.5

What you need to know

The main attraction to tooth whitening is the aesthetic boost, but like any procedure, there can be side effects.

“One of the most common side-effects would be tooth sensitivity,” says Dr Thomas Cocks from The Dental Centre in Broken Hill, NSW. “This often occurs if the patient has some underlying dental problem such as decays, cracks or sometimes even gum disease. In a dental practice we have many different types of desensitising agents and materials we can use to reduce the sensitivity.”

If you’re considering whitening your teeth, keep in mind it won’t work on crowns, veneers or fillings1 – which could mean a colour mismatch between teeth that have been whitened and those that have been restored.4

“You need to make sure there is no decay, no problems with gum disease or cracks on the teeth,” says Dr Cocks. “And if your teeth are discoloured from trauma – let’s say a whack to the face where the tooth’s gone black – or you’ve had previous root canal therapy and the tooth’s gone dark, you have larger, older crowns or restorations or some form of internal tooth staining, then whitening is unlikely to be effective.”

It’s important to know that tooth whitening is not recommended if you’re pregnant or breastfeeding.3

kissing couple

Dentist whitening

One advantage of having a dentist whiten your teeth is that they’re allowed to use a stronger bleach formula – up to 38% hydrogen peroxide (other practitioners are restricted to formulas of 6% hydrogen peroxide),2 which can be more effective. They’re also trained and experienced in oral health, so they’re well equipped to determine what’s right for you.

There are two forms of whitening treatments administered by dentists, oral health therapists and dental health hygienists: take-home or in-practice whitening.

“Take-home whitening involves us taking models of your teeth and constructing perfectly fitting trays that adapt well to your teeth,” Dr Cocks says. “You can then apply whitening gel in the comfort of your own home.

“The dental practitioner places a barrier over the gums and applies a very high concentration of whitening agent onto your teeth. There is a slightly higher chance of having sensitivity during this procedure, so for my patients I always give them a take-home pack and a desensitising treatment.”

DIY kits

According to research by the Australian Dental Association (ADA), 50% of people who opt to whiten their teeth are going the DIY route, using products such as whitening strips and kits available online and at some pharmacies.1

“The law in Australia doesn’t allow consumers to purchase higher concentration whitening products by themselves, so the concentration of peroxide in these kits is quite low,” Dr Cocks says. “All the evidence shows that these are ineffective because of the low concentration.”

Unfortunately, says the ADA, many people appear to be applying whitening products more often – and for longer – than recommended.1 If bleach is in contact with your gums for too long, burns can result.4

And there is some evidence that incorrect or overuse of whitening products increases the risk of negative side effects and damage to the teeth or gums.4

Salon and kiosks

When it comes to whitening services offered at shopping centres, hair salons and beauty parlours, be aware that the people offering these treatments aren’t usually dental professionals. That means they aren’t qualified to assess whether your teeth will even respond to whitening, let alone accommodate for potential problems such as exposed root surfaces or cracked enamel.2

“They’re not legally allowed to use higher concentrations of peroxide so the result isn’t as good or as long lasting as it could be,” Dr Cocks says. “Often they’re using light to activate the gels, and the reason this appears to whiten your teeth a little bit more effectively is the light actually dehydrates the tooth. This provides an improved appearance at the time of whitening, but it rapidly goes away after the saliva covers the teeth, and after a few hours that effect wears off.”

Dr Cocks recommends you steer clear of such providers when it comes to whitening.

“I’ve seen a lot of horror stories of burned gums and painful teeth, and unfortunately they’re a regular occurrence at my practice after these treatments by people who aren’t particularly well trained in what they’re doing,” he says.

Teeth-whitening toothpaste

While charcoal toothpastes often claim they whiten teeth, a scientific review found little evidence to back this up. Not only that, but Dr Cocks says that can even be harmful.

“The problem with these abrasive toothpastes is that they can sometimes cause a little bit of extra wear and tear, so they’re really not that effective,” Dr Cocks says.

To learn more about charcoal toothpastes, read this article.

Go Back to Top

1 Teeth whitening: Surging popularity brings issues to resolve [Online] 2019 Available from: www.ada.org.au

2 Teeth whitening treatments [Online] 2020 Available from: www.choice.com.au

3 Teeth whitening [Online] 2018 Available from: www.healthdirect.gov.au

4 50 shades whiter: what you should know about teeth whitening [Online] 2018 Available from: theconversation.com

5 What causes discolored teeth and is there any way to cure or prevent staining? [Online] 2016 Available from: now.tufts.edu

The purpose of this article is to promote better understanding of dental health topics. It’s not meant to replace professional advice or diagnosis. Always talk to a dentist, doctor or other qualified healthcare professional if you have a question about dental or medical conditions.
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