A 3-year-old Nelson boy who had to have 11 rotten teeth extracted under general anaesthetic.

More Kiwi pre-schoolers are requiring hospital treatment for severe tooth decay. Cate Broughton reports on a problem dentists are struggling to cope with.

Senior Christchurch hospital dentist ​Joanna Pedlow​ spent most of Wednesday extracting, filling or capping severely decayed teeth of six children aged between 3 and 8-years-old. Such procedures take place regularly.

For each hour-long procedure the children are under a general anaesthetic while Pedlow​ attempts to salvage teeth from the ravages of decay.

Rob Beaglehole Rotten teeth extracted from a Kiwi child. The New Zealand Dental Association is calling on maraes to adopt a water and milk-only policy.

Most parents struggle with the news that their children's teeth require major work.

"They can be quite shocked, it's quite emotional for them," Pedlow says.

A diet heavy in high-sugar food and drink, often combined with a lack of regular brushing using fluoride toothpaste, causes decay.

"It's never done deliberately, it's just not realising the impact of the lifestyle," she says.

The number of teeth removed varies between four and 14 per child.

Pedlow​ says occasionally they have to remove all a child's teeth.

"A lot [of parents] say they have a healthy diet and brush their teeth, but something has gone wrong along the way."

Canterbury District Health Board (CDHB) community dental service clinical director Dr Martin Lee says last year one 4-year-old boy had eight teeth pulled out and six filled in one operation.

"He was much, much happier afterwards, despite the gaps."

Decay rates in Canterbury and nationally reveal a clear link between tooth decay, deprivation and ethnicity.

The 2015 Canterbury data showed 62 per cent of Pacific Island 5-year-olds had tooth decay. Almost half (47 per cent) had severe early childhood decay.

Of the Maori school starters 58 per cent had tooth decay, while 39 per cent experienced severe early childhood decay.

Lee says the problem of early tooth decay was also growing in European and Asian ethnic groups.

Between 2009 and 2015 there was a 17 per cent increase in the average number of decayed, extracted, and filled teeth in those children from 3.6 to 4.2.

New Zealand Dental Association spokesman Rob Beaglehole​ says the problem affects the poor disproportionately.

"You can clearly map out tooth decay rates with not only ethnicity, but also with postcode, it's a disease of poverty."

Just getting to appointments is challenging for some parents, Lee says.

"Some of these families have real issues of transportation and they don't turn up for appointments for quite legitimate reasons."

Getting in touch with families to arrange appointments is difficult as many people do not have landline phones and change their cellphone numbers or ran out of credit intermittently.

"We try to get in touch, but give up after a while and then we don't see the child until it's a dental disaster."

CDHB executive director of Maori and Pacific health Hector Matthews says more work is required to educate parents.

"Unfortunately a lot of parents think 'oh well they are baby teeth, once they get their adult teeth we can improve their oral health then'."

The opening of community dental clinics in areas where there is a higher proportion of Maori and Pacific families, including Aranui and Hillmorton, is a positive step.

Matthews says the real culprit is a high sugar diet.

"I grew up in a New Zealand where I drank milk every day because it was four cents a bottle and no-one drank soft drink because it was too expensive."

Matthews is part of a growing public health movement calling for a tax on sugary drinks.

"I get the supermarkets are trying to make a living, but the bottom line is they are making it by selling harmful products to our kids and families and I think we need to be more bold as a country about this."

Beaglehole​ says sugar is "decimating" teeth in Maori and Pacific Island communities. Decayed teeth are painful for children and costly to fix.

"If kids are losing their teeth at a young age they're going to be in pain and they will be suffering for weeks and weeks before they even get to the doctor."

Every treatment under general anaesthetic cost about $4000.

Nationally, each year just over 5000 children aged eight and under received treatment for severe tooth decay using a general anaesthetic.

The number of 3-year-olds referred for treatment under sedation or general anaesthetic from community dental clinics increased from 8 per cent in 2009 to 13 per cent in 2014.

Rates of treatment under general anaesthesia have tripled since 1990. Beaglehole​ says consumption of sugary drinks is largely responsible.

"There's only one cause of tooth decay and that is a diet high in sugar - particularly sugary drinks."

Brushing teeth twice a day with fluoridated toothpaste and water will significantly reduce the risk of decay. Teeth will get "hammered" without regular brushing, he says.

He has called on all maraes to adopt a milk and water-only policy.

"...this is something that could be instigated within a short period of time and at the end of the day is going to reduce pain and suffering of Maori kids."

Some maraes have already taken the message on board.

Rapaki Marae has been sugar-free for about three years, Rāpaki hapū member and CDHB health promoter Christina Henderson says.

"We've eliminated sugary drinks all together, it's water with lemon, or mint or just water."

Maori health provider He Waka Tapu Dallas Hibbs​ says maraes were increasingly aware of promoting healthy lifestyles.

"For most of our kids, that is not an ordinary part of their life, so the messages need to be in schools and pre-schools."

He says more promotion of good oral health care is needed "for those who are not putting fluoridated toothpaste and dental floss in to the trolley".

Lee says some parents of children requiring hospital dental treatment have good oral health themselves, but adopt a more permissive parenting style.

"Then they get a nasty shock and change things in a big way after the treatment."

Other parents have terrible teeth themselves and their whole social network, including children, are the same.

"There's an expectation of problems, and it becomes the norm."

While New Zealand has strong access to dental services for children, access to adult dental care is poor.

"It sends a bad message about the importance of oral health."

Lee says he would fluoridate Canterbury's drinking water as a first step towards lowering the rates of decay.

"It costs next to nothing and it would work."

Next on his wishlist is a social marketing campaign to promote tooth brushing followed by a tax on sugary drinks and increased health literacy.

Lee says there is no doubt the "sugar-soaked environment" must be addressed, but a tax on soft-drinks will not be a quick fix.