21/06/2017 7:00 AM AEST | Updated 22/06/2017 11:23 AM AEST

Is Bottled Water Bad For Your Teeth?

'There has been an increase in the amount of decay we are seeing in children.'

Consumption of bottled water in Australia is on the rise: fact.

In 2015, Australians purchased over 726 million litres of the stuff, despite the fact it's literally on tap for free (and we won't even begin to talk about its effects on the environment).

But there's another question we should be asking about bottled water, and that's what it's doing to our teeth. Given many brands of bottled water do not contain fluoride, has our consumption reached such levels that it's affecting our teeth?

According to Dr Christopher Ho of CARE Dentistry, it's actually hard to say.

"When it comes to bottled water, what I can say is there has been an increase in the amount of decay we are seeing in children -- so kids who still have their baby teeth. There is a definitely a higher incidence of decay in that population group."

In fact, Ho says the level of decay he is currently seeing is one of the highest recorded in the last decade.

"Based on the figures, it's not as much as it was before fluoride was introduced [to tap water] but it's definitely one of the highest we've seen in the last seven to 10 years. And mostly this is being seen in kids' teeth."

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Tooth decay in Australian children is on the rise.

Professor David Manton from the Faculty of Medicine, Dentistry and Health Sciences at the The University of Melbourne emphasises that dental decay is an important issue in Australia.

"Nearly 50 percent of Australian five year old children have experience of dental decay in their primary (baby) teeth. By the time Australian adolescent get to 15 years of age, they have an average of more than 2.5 permanent teeth affected by decay," Manton told HuffPost Australia.

However Ho states it's too simplistic to attribute this rise in decay to bottled water alone, though he does believe its popularity is a contributing factor.

"I do think it has an effect, yes. But it's not just bottled water. Lots of kids are having more sweet drinks, more fruit juices, and that contributes as well. It's very hard to pinpoint whether it's bottled water or something else, like a poor diet."

Manton agrees that sugar is part of the problem.

"Decay caries is caused by a diet high in sugars causing the plaque on the teeth to become efficient at turning the sugars into acids, that subsequently dissolve the tooth structure and lead to holes in the teeth developing. The best way to decrease decay risk is to eat sugars infrequently, however this is often difficult with a modern processed diet. Basically, the continuing poor oral health of the Australian population is due to our dietary habits, so the best way of reducing the decay rate is to have a healthy diet low in sugars," Manton said.

"The most effective preventive agent we have for decay is fluoride -- water fluoridation and fluoridated toothpaste are the primary methods for getting fluoride in contact with the teeth, as this is the way fluoride works, as a topical effect. Old theories involved fluoride being incorporated into the tooth structure during their development inside the gums, however, in the past 30 years or so this theory has become redundant and it is realised that fluoride works at the tooth surface, decreasing the dissolution of the tooth and increasing tooth minerals being replaced in the tooth structure. This new 'remineralised' structure has fluoride in it, which makes the tooth less soluble. Fluoride can also be applied in stronger concentrations by your dentist in areas of decay risk," Manton said.

It's also worth pointing out drinking tap water is not our only source of fluoride, with some foods being sources of fluoride as well as man-made products such as fluoride toothpastes.

This creates what Ho refers to as the 'halo effect', meaning even without the primary source of fluoridated drinking water, children and adults alike are still being exposed to fluoride depending on their diet and dental hygiene practices.

We can still be exposed to fluoride in some foods as well as toothpastes.

Flouride toothpaste is useful for both children and adults, and Manton suggests the following advice.

"As the action of fluoride is topical, it is effective in both children and adults, although the concentration of fluoridated toothpaste for children may be lower than adult paste, as if they swallow too much fluoride when they are an infant, this may lead to an increased risk of fluorosis, so it is important that only a small amount of paste is put onto the brush, and the paste is spat out after brushing -- and remember -- don't rinse after brushing, as the small amount of paste left behind keeps on preventing decay," Manton said.

But this still doesn't detract away from what dentists are seeing walking through their practice doors: and that's children with decaying teeth. Of course, you could argue that as baby teeth are only temporary, it's not such a big deal.

"Because they are replaced with adult teeth anyway, yes, you could say it doesn't matter," Ho said. "But you are still putting the child through a lot of trauma, be it fillings or extraction or even root canal. You are getting a lot of children who are becoming very scared of the dentist and could have dental problems in the future as a result of avoiding appointments.

"It's not great that all these kids are coming in and having multiple teeth filled and extractions."

Furthermore, unless habits change, children will experience the same issues with decay in their developing adult teeth.

High sugar diets are also thought to be a major source of tooth decay in children.

"The same thing will happen with even the adult teeth," Ho says. "Fluoride is what makes the teeth strong. As the tooth is developing, you can expect adults to have more incidence of decay as well. I think there is the benefit of that halo effect, so it remains to be seen how much [bottled water has to do with it].

"I will see we won't see the amount of decay now as we did in the pre-fluoride days, but there are still people coming in with decay, and it shouldn't be happening."

As for what to do about it?

Firstly, watch how much access your children have to sugary food and drinks. And secondly, promote drinking from the tap, particularly when at home. (Ho is at pains to point out a bottle of water when out and about is highly preferable to a soft drink, juice or other transportable drink that may be available.)

"At home there's no reason why you wouldn't have tap water," he says.

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