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Dental health in Aussie and Kiwi children

How are our children’s teeth and how can we best promote dental health?

What are the factors that contribute to the risk of decay?

The significant social and geographical inequality in oral health status points to the significant influence of social, economic, environmental and cultural factors in the development of decay.

The three main pillars of oral health are:

  1. Water fluoridation
  2. Oral hygiene (teeth brushing)
  3. Diet (especially sugars and other fermentable carbohydrates)

Water fluoridation

The Australian Institute of Health & Welfare (AIHW) reports access to fluoridated water is high, ranging from 76% in Queensland to 100% in the Australian Capital Territory (ACT). Children in cities have highest access while children in regional areas have poorer access, down to 55% in remote and very remote areas that rely on tank water and bores. Children in high-income households are also more likely to drink tap water (79%) than low-income households (65%)

The latest data show 69% of children aged 4-14 were brushing their teeth twice per day as recommended, but it was only 54% in indigenous children and 59% in low-income households. Many disadvantaged households find private dental treatment unaffordable and waiting periods for public treatment are long.

In New Zealand, only 60% of the population have access to fluoridated water. Children with fluoridated water supplies have better oral health than those without. People on the North Island were four times more likely to have access to fluoridated water than those in the South Island.

How are our children’s teeth?

Researchers from the University of Adelaide, South Australia were commissioned to perform a cross sectional study of 24,664 children 5-14 years in 2012-14. The Oral health of Australian children report concluded that despite some improvement, child oral health has remained a significant population health issue. There are social inequalities in child oral health and substantial social patterning of oral health status, dental service use and dental health behaviours.

The AIHW report Australia’s Children (2020) says while most Australian children are healthy, safe and doing well, a child’s outcomes can vary on where they live and their family’s circumstances. In 2011, dental decay was the 7th leading cause of total disease burden among boys aged 5-14 (accounting for 4.3%), and the 4th leading cause among girls (5.1%).

The 2012-14 Oral health of Australian children research is the most recent nationally representative data and it reported:

  • 2 in 5 children (42%) had experienced decay in their primary (baby) teeth;
  • 1 in 4 (24%) children had experienced decay in their permanent (adult) teeth;
  • Children in low-income households were twice as likely to have untreated decay in their primary (36%) and permanent teeth (15%) as children in high-income households (18% and 7% respectively);
  • 6 in 10 (61%) indigenous children had experienced decay in their primary teeth and 1 in 3 (36%) experienced decay in their permanent teeth, compared to 4 in 10 (41%, primary) and 1 in 4 (23%, permanent) respectively in non-indigenous children.

In New Zealand, the oral health status of children is slightly worse. Data from 2018  found Maori and Pacific children had higher caries scores than children of other ethnicities, especially at 5 years old when decayed, missing & filled teeth (DMFT) scores were more than double in Maori and Pacific Children. The data showed no difference in caries incidence between fluoridated and non-fluoridated areas in five-year olds (40% incidence), but a disparity was apparent at 12 years of age (31.5% in fluoridated areas vs 36.7% in non-fluoridated areas).

In contrast to Australia where children’s oral health has stayed about the same over the past two decades, oral health in New Zealand children has improved since the year 2000.

Diet and dental health in children

The potential for foods and drinks to cause dental caries is called cariogenicity and can be influenced by numerous factors. The main factors influencing the cariogenicity of a food are:

  1. Amount of fermentable carbohydrate
  2. Frequency of intake
  3. Food form
  4. Nutrient composition

High intake of added/free sugars is associated with dental caries. The evidence informing the World Health Organisation (WHO) sugar guidelines says there is moderate quality evidence showing caries are fewer when free-sugars intake is less than 10% of energy. The evidence for sugars intake less than 5% of energy is of low quality.

However, starches as well as sugars- collectively called fermentable carbohydrates- can fuel plaque bacteria that cause dental caries. The Australian Dental Association (ADA) says crackers and chips can also cause acid attacks on tooth enamel.


The ADA recommends limiting snacking between meals to give the teeth a break from plaque acid attack, and limiting sugary treats to meal times rather than between meals.


Foods that stay in the mouth and adhere to teeth are particularly risky as they fuel plaque bacteria for longer. Hard sweets that take a while to suck (such as lollipops) are high risk, as are biscuits, bars and slices that can get caught in the teeth. Dried fruit may also contribute to caries, although the evidence for this is weak and the presence of anti-microbial compounds and sorbitol, and their saliva-inducing effect, may ameliorate any negative effects of the natural cariogenic sugars present.  

One study measuring oral clearance found foods containing sugars clear more rapidly than starchy foods; there was more lactic acid on the teeth 2 hours after eating potato chips than jellybeans, chocolate or raisins.

Despite containing cariogenic natural sugars, raw fruits and vegetables require significant chewing and invoke good salivary flow that neutralises dental risk. They are tooth-friendly snacks.

Sugar containing drinks are less retentive on the teeth because they are consumed quickly (faster oral clearance), however drinks sipped slowly through bottles with sipper nozzles, or young children drinking milk from a bottle while in bed, can pool the liquid around the teeth over a longer period and this is hazardous. Carbonated soft drinks have the additional hazard of being acidic which can cause dental enamel erosion. Drinking through a straw and drawing fluid to the back of the mouth away from the teeth reduces the risk.

What about fruit juice?

A Systematic Review examining 100% fruit juice and dental health found the evidence inconclusive for any link with dental decay or erosion. Results from prospective studies in adolescents and children found no association. A more recent study of the US NHANES cohort found no association between early childhood caries (ECC) and 100% fruit juice. Polyphenols in fruit juice may reduce its cariogenic potential. Cranberry polyphenols have been shown to reduce the activity of plaque bacteria.


The advice to limit snacking to give teeth a break from plaque acid attack may be unrealistic for children, however there are foods considered ‘tooth-friendly’ because of their low cariogenicity. Dairy foods such as milk, cheese and yoghurt all contain calcium, phosphate and protein which favour remineralisation of tooth enamel. As a bonus, they are also nutritious core foods. Milk is rapidly cleared from the mouth (unless given in a bottle to a young child when resting) and cheese is considered anticariogenic because it invokes high salivary flow and this has a buffering effect on plaque acids. Even flavoured milk and yoghurts have low cariogenicity, and milk and yoghurt with probiotics are effective at reducing plaque bacteria.

Thumbs up for gum

The Australian Dental Association (ADA) says chewing sugar-free gum for 20 minutes after meals produces more saliva and helps neutralise plaque acid. This is helpful during the day when tooth brushing is less practical. It is also useful after acidic drinks.

Oral health promotion

Most dental disease is preventable. The primary nutrition strategy to reduce caries risk is promoting a nutritionally adequate and balanced diet as recommended by Dietary Guidelines. Public health measures include fluoridated water, application of topical fluoride, improving oral hygiene and good access to dental care. Addressing the social determinants of poor oral health is more challenging.

A national health marketing campaign in the UK called Sugar Smart aimed to raise awareness about the sugar content in foods and drinks and encourage parents to reduce their children’s intake. An evaluation of the campaign showed a reduction in mean total sugar intake of around 2% however this was not sustained one year after the campaign. Percentage energy from fat increased across all time points, possibly due to higher fat snacks replacing sweet snacks. A slight reduction in fresh fruit occurred despite campaign messaging promoting fresh fruit, perhaps due to competing media messages that demonise all sugars. Parents expressed confusion over ‘good’ and ‘bad’ sugars, and uncertainty about which sugars to avoid hampered their efforts to change.

An Australian-led Cochrane Database Systematic Review of community-based population level interventions for promoting child oral health concluded the evidence was ‘low certainty’ that interventions that combine oral health education with supervised toothbrushing or professional preventive oral care can reduce dental caries in children. Other interventions that aim to promote access to fluoride, improve children’s diets or provide oral health education alone show only limited impact. Cost-effectiveness, long term sustainability, equity of impacts and adverse outcomes were not widely reported. Better quality evidence is required to inform policy and action.

One encouraging example of successfully improving oral health in children is a program that targets Australian indigenous children called the Dalang Project. This co-designed project included Aboriginal and Torres Strait Islander people throughout the planning and implementation process. It embedded oral health therapists within an Aboriginal Controlled Health Service and developed the local workforce. In three years, they achieved a reduction in tooth decay, plaque scores and gingivitis among children. The project saw an increase in oral hygiene behaviour, water drinking and reduced consumption of sugar-sweetened beverages. The project is working with communities in rural towns to install public drinking fountains to make drinking water easier and more convenient (Read our article on nudge science).

Further information

Oral Health Promotion Resources are available from The (Australian) National Oral Health Promotion Clearinghouse.


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