Dentists say the proliferation of "natural" toothpaste, aka fluoride-free, will usher in epidemic of dental decay. (Video first published in October 2018)

The rising popularity of fluoride-free toothpaste could usher in an epidemic of dental decay, dentists say.

Ecostore launched its range of natural toothpaste in July, joining Grin and Red Seal products on supermarket shelves.

A flurry of promotion has accompanied the appearance of the products in supermarkets, including free samples to My Food Bag customers and social media advertising by celebrity influencers.

DAVID WALKER/STUFF Dentists say the proliferation of natural, fluoride-free toothpaste will usher in an epidemic of dental decay that New Zealand hasn't seen since the 1960s.

The new fluoride-free products use natural ingredients such as kanuka oil, magnolia bark extract, propolis and red seaweed, and claim to help "reduce cavities", "neutralise plaque acids" and "keep teeth and gums healthy".

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But dentists say the products will achieve little to nothing without fluoride.

JOSEPH JOHNSON/STUFF Community dental service clinical director Martin Lee is worried customers don't realise natural toothpaste doesn't contain fluoride.

Canterbury District Health Board community dental service clinical director Martin Lee said there was a huge improvement in oral health after the introduction of fluoride toothpaste in the 1970s.

Fluoride worked to strengthen tooth enamel "by a factor of 10" against acid formed by oral bacteria, he said.

"If you don't use a fluoride toothpaste you are going to dramatically increase the risk of getting tooth decay."

SUPPLIED New Zealand Dental Association vice president Katie Ayers says people who use natural toothpaste will get more dental decay as the products do not contain fluoride.

Lee said if fluoride-free toothpaste was sold in large quantities, it would "end up causing an epidemic of tooth decay in adults and children".

The New Zealand Dental Association (NZDA) said all toothpaste should contain fluoride.

The organisation representing dentists is concerned customers will inadvertently buy fluoride-free toothpaste without realising the implications, vice president Katie Ayers said.

DAVID WALKER/STUFF The companies making natural, fluoride-free toothpastes say they offer consumers more choice about what chemicals they consume.

"There have been fluoride-free alternatives for a long time but they haven't been mainstream. Now, these products are everywhere and often being promoted by the supermarkets as well."

Ayers said improved labelling would ensure customers were well informed.

The association took its concerns to the Ministry of Health this month.

Red Seal senior brand manager Christel Maurer said the company believed there could be "negative implications for some people if their fluoride consumption is too high".

"We provide a range of fluoride-free toothpaste to ensure individual New Zealand consumers have a choice about the level of fluoride they are exposed to."

Grin Natural director Tara Tan said the company wanted to offer customers another option for toothpaste without "chemical nasties" such as triclosan, but was not against fluoride.

"Customers should be aware of the chemical nasties in the mainstream toothpaste, which a lot of people don't know about."

Ecostore research and development manager Huia Iti said sales of its toothpaste were "tracking well" and feedback had been "extremely positive".

The products had been tested in an in vitro environment by an independent laboratory in Australia and "shown to be effective in reducing populations of the main bacteria found in the human mouth".

Lee said plaque removal alone did not prevent tooth decay.

"People had been using toothpaste for centuries, but it wasn't until they put fluoride in it that it really started preventing tooth decay."

The Ministry of Health advises people to brush twice a day with fluoride toothpaste.

Team leader population health and prevention Barbara Burt said the ministry met with the NZDA on October 9 to hear its concerns.

"The ministry is not considering any new labelling requirements for fluoride-free toothpaste," she said.