The dramatic decline in dental decay in developed nations may be one of the great public health success stories this century, but how exactly has it been achieved?
In the latest installment of #TalkingTeeth, a consortium of researchers from Western Australia, Saudi Arabia and India reflect on the drivers of improvements to oral health in recent decades.
It follows this piece on the gap in oral health for Aboriginal and Torres Strait Islander communities published earlier this week as part of our #UnmetNeedsInPublicHealth series.
Kate Dyson, Marc Tennant, Estie Kruger, Alaa Al-Sharif and Rajeev B R write:
No story in health is as simple as it seems, and the astounding reduction in tooth decay that has been occurring in developed countries over the last 50 years is no exception.
Interestingly, experts are not fully agreed on exactly how this epic achievement has occurred, however some scholars believe the humble toothbrush deserves more credit.
We can get a sense of the staggering scale of this turnaround in dental health by comparing tooth decay levels in 12-year-old children in the 1960s with levels in 12-year-old children today.
Fifty years ago, 12-year-olds had nearly 10 decayed teeth each on average. Today’s 12-year-olds barely share one decayed tooth between two of them.
One prevailing public health narrative attributes much of tooth decay’s demise to the addition of fluoride to drinking water, salt, or, in some places, milk. This discourse is especially strong in countries that rest on fluoridation programs, such as Australia.
Whilst this is not a discussion of the rights and wrongs of fluoridation programs, and it is accepted that these public health measures have documented benefit, they cannot account for the eradication of toothache from the lives of many people globally.
The Queensland experiment
An appreciation of the complexity in evaluating the therapeutic role of fluoridation programs can be gained by considering an interesting natural public health experiment that has been happening in Australia over the past 50 years.
Until recently, much of the State of Queensland, with a population of 4.5 million people, has been drinking non-fluoridated water. By contrast, most other Australians have been drinking fluoridated water since water fluoridation began in the 1960s and 70s.
In simple terms, therefore, one might expect that tooth decay levels among Queensland children would have remained very high, reflecting the pre-fluoridation situation seen Australia-wide in the 1960s. This is not the case.
Queensland’s 12-year-olds have experienced a reduction in tooth decay commensurate to fluoridated regions of Australia over the last 50 years. Any differences compared with other areas of Australia are very small compared to the massive overall shift.
Intriguingly, a similar story has unfolded in comparable countries worldwide, where tooth decay levels have plummeted irrespective of the implementation of community fluoridation programs.
For example, countries without water, salt or milk fluoridation, such as Iceland, Italy, and Japan, have seen decay levels among 12-year-olds drop to lows on par with Australia and many other developed nations.
How can we account for this?
A topical twist
Only relatively recently have we come to understand that fluoride’s protective action occurs on the tooth surface by topical exposure, and therefore, consumption of fluoride is not required.
There is a strong argument that personal oral hygiene activities, including brushing with fluoridated toothpaste, are the major drivers of plummeting tooth decay in developed countries.
Increased dental hygiene awareness combined with widespread use of fluoridated toothpaste occurred at around the same time as community fluoridation programs were introduced, so it is difficult to disentangle the two stories scientifically.
Consequently, due to overlapping effects, regions with fluoridation programs, may be a little blind to the positive health effects that are driven through good home hygiene habits.
Tooth brushing is not a new phenomenon. The prototype of the contemporary toothbrush is many thousands of years old and much of the world still relies on these handcrafted brushes from small branches and roots of trees such as mango and neem.
One of the most common trees used is Salvadora persica, which grows across Africa, through the Middle East and into Asia. Interestingly, Salvadora persica stems reportedly contain fluoride, silica (an abrasive) and antibacterial compounds. As such, traditional forms of tooth care may have much in common with more recently introduced methods.
Public health potential
Traditional approaches however, have the important benefits of being low cost, environmentally protective and boosting infection control through single use.
The cost of contemporary oral hygiene products is prohibitive to many people across the world. In some places, annual toothpaste for one person costs up to 4% of annual household expenditure.
As a simple and inexpensive global initiative, facilitating effective basic tooth cleaning practices has the potential to prevent the pain and suffering of toothache for millions of people, and thereby enhance human welfare on a major scale.
In developed nations such as Australia, a strong case exists for adopting simple policy settings to make toothbrushes and fluoridated toothpaste more available to disadvantaged groups. Effective policy settings designed to reduce sugar consumption are also essential in this task.
The promotion of some form of affordable fluoride toothpaste is important for improving equity in oral health.
Kate Dyson, Marc Tennant and Estie Kruger are from the University of Western Australia’s International Research Collaborative – Oral Health and Equity
Alaa Al-Sharif is from Saudi Arabia’s Taibah University College of Dentistry
Rajeev B R is from the Society for Community Health Awareness Research and Action, India