There are around 200,000 hospitalisations across Australia every year for dental-related conditions, but how many of these can be prevented through primary care?
In this latest piece for our #TalkingTeeth series, Estie Kruger, Alaa Alsharif and Marc Tennant explore hospitalisations due to oral health and whether dental admissions could be reduced or — counter-intuitively — increased through greater efforts at the primary care level.
Estie Kruger, Alaa Alsharif and Marc Tennant write:
Potentially avoidable hospitalisations are “those hospitalisations which could have been avoided with access to quality primary care and preventative care”. 
When it comes to dental health, they can include the following conditions (as recognised globally and by the AIHW):
- dental caries
- other diseases of the hard tissues of the teeth
- diseases of the pulp and periapical tissues
- gingivitis and periodontal diseases
- other disease of the gingival and edentulous alveolar ridge
- other disorders of the teeth and supporting structures
- cysts of the oral region
- stomatitis and related lesions
- other diseases of the lip and oral mucosa
But how many hospital admissions do we actually see in Australia due to these conditions, and what proportion of them are actually preventable?
It’s a complex question. ‘Hospitalisations’ in dentistry extend well beyond the narrow definition offered above and many (actually the majority) sit outside the scope of what’s considered ‘preventable’.
In Australia, the total number of hospital separations (i.e. completed episodes of care) for dental-related conditions is in the order of 200,000 per year.
Of these 200,000 separations about 120,000 are for impacted teeth: wisdom teeth predominantly . Australia has one of the highest rates of hospitalisation for impacted tooth extraction in the world. Ten times the UK and seven times France .
Clearly, these are avoidable, but strictly speaking they don’t fall within the definition of preventable hospitalisations. Why? Because it’s not primary care that will prevent these, but the application of evidence-based guidelines (eg NICE guidelines) for the referral of these cases to hospital in the first place.
In round numbers that’s 60% of all dental separations that are not counted as preventable (in fact enhanced primary care could actually increase dental hospital admissions, but more on that later).
This is not to say that good policy and good governance won’t make a substantial difference in admissions. This is the real elephant standing quietly in the theatre corner.
A tale of two caries
As for the next-largest, we estimate that some 60,000 separations per year are for dental caries and associated conditions .
It’s immediately clear that these are preventable with good primary health. But there is much more to the story; the devil is in the statistical detail.
Some of the highest rates of caries are in the most affluent parts of the country, many with full insurance coverage, thus having gold-class access to primary care already.
Nearly two thirds of cases in WA are treated in the private sector, half with insurance and half from the most affluent 40% of the population . And, 80% are from the city and associated areas where prevention such as fluoride is optimised and service access is outstanding.
Given this, the question is: if we drive more primary health services are we really going to dramatically reduce admissions?
It is important to understand the association between primary health care and preventable hospitalisations.
Previous studies have identified that this relationship is not linear but U-shaped, with too little primary health care leading to an excess of hospitalisation, and too much also driving an increase [7,8]. This relationship was found to also apply to dental conditions, with high rates of hospitalisation among poorer, rural, and Aboriginal groups (those with limited access to primary oral health care), and high rates also seen among higher socio-economic, non-Aboriginal, and urban dwelling groups (with good access to primary health care) .
There are differences in the mix of conditions however, with more disadvantaged groups more likely to be admitted for pulpitis, cellulitis and periapical disease (possible result of untreated caries), and least disadvantaged groups more likely to be admitted for caries (diagnosed in primary care and referred for treatment under general anesthesia).
A strong argument can be made that there are factors other than primary care access driving some of this demand for hospital time and space.
We have previously discussed the “public health experiment” that is the Australian Capital Territory: a very wealthy population, 100% access to water fluoridation, “everyone” in walking distance of a clinic (a wee exaggeration) — yet dental decay is still present and preventable hospitalisation rates remain in the 2-4 cases per 1000 people band comparable to other states . There is no absolute zero achievable.
Even more importantly, a strong argument can be made that the poor and marginalised are accessing hospital-based care at rates lower than the wealthy.
Under these conditions, targeted primary health care (to those at known risk of dental decay) would actually have the counter-intuitive effect of driving up admissions. This is, clearly, not a bad outcome, but it’s not addressing the hypothesis that hospitalisations are prevented through primary health care; rather, the opposite.
The best of the rest
A number of other conditions round out the complete picture of dental-related hospitalisations. These occupy hospital beds and time, but are not technically classed as preventable.
Oral Malignancy: In WA these sinister conditions (excluding lip cancer) account for some 700 admissions per year; extrapolating to Australia this is about 8000. Clearly, enhanced primary health may reduce the “time-to-diagnosis” and thus improve life expectancy from treatment. However, with grim mortality rates ranging from 40% to 60% even under the best of health service conditions, we should continue, no matter the level of primary health care, to expect little change in admissions.  In fact, looking at the age distribution of those admitted, one would project with an ageing population this will be a growing group for the next 20 years at least. [10,11]
Jaw fractures: In WA these amount to some 600 admissions per year . Extrapolating to Australia this is about 7000 — in relative terms, tiny to the numbers for impacted teeth (120,000) and decay (60,000). More importantly, these injuries are not strictly preventable through primary health care. Of course they can be reduced through action on poverty, marginalisation and violence in society — particularly by addressing the plight of Aboriginal and Torres Strait Islanders — but one needs to take a very broad view of the definition of dental primary health to be inclusive of these factors. No enhanced primary dental care or prevention is going to reduce jaw fractures. Instead, it is for us as a society to close the gap on the ’causes of the causes’.
Flipping the script
So, to return to our core hypothesis: the reduction of hospital admissions through enhanced primary and preventive approaches.
The big admission load from oral health — impacted teeth extraction — is reducible, as is evidenced by actions in other countries, but it is not through increased primary health care. One could argue in fact, that in the current climate of a “guideline vacuum”, greater primary health care access may increase this number through increased referrals — a boon for the private hospital sector.
The second largest load is dental caries, which could, at a population level, see increased admissions for the not-so-well-off. This may be a good outcome of primary health care intervention, but not a reduction as being contemplated in the present scenario.
So what will increased dental primary health care actually do for hospital admissions, both public and private? We leave the readers to draw their own conclusions, but it must be acknowledged that substantially reducing admissions is unlikely.
Good policy and clear evidence-based guidelines for referral, applicable to all, will make the most substantive reductions. And even then, we have to accept that private hospital admissions from the wealthy (both in service access and assets) core of cities, will continue to distort service utilisation in the economic model of Australian dentistry.
However, if one divorces the discussion of good primary health and prevention from the goal of reducing hospital admissions and views it instead as a quality community initiative, it becomes a very different debate.
Targeted to current gaps in the system, good primary health and prevention will make a substantial contribution to reversing the massive inverse care law effect that the Australian population sees in oral health services. And that would be something to smile about.
Estie Kruger, Alaa Alsharif, and Marc Tennant are from the International Research Collaborative – Oral Health and Equity at the University of Western Australia
 Chrisopoulos S & Harford JE 2013.Oral health and dental care in Australia: key facts and figures 2012. Cat. no. DEN 224. Canberra: AIHW
 Whyman RA, Mahoney EK, Morrison D, Stanley J. Potentially preventable admissions to New Zealand public hospitals for dental care: a 20-year review. Comm Dent Oral Epidemiol 2014, 42: 234-244.
 Department of Human Services. Demographic analysis of dental ambulatory care sensitive condition (ACSC) admissions in Victoria trends, 1997-98 to 2004-05. Melbourne: Department of Human Services; 2007.
 Australian Institute of Health and Welfare 2014. Australian hospital statistics 2012–13. Health services series no. 54. Cat. no. HSE 145. Canberra: AIHW.
 A. A. Anjrini,1 E. Kruger and M. Tennant. International benchmarking of hospitalisations for impacted teeth: a 10-year retrospective study from the United Kingdom, France and Australia. Br Dent J. 2014;216:E16. doi: 10.1038/sj.bdj.2014.251
AT Alsharif, E Kruger Tennant M. Dental hospitalization trends in Western Australian children under the age of 15 years: a decade of population-based study. Int J Paediatr Dent. 2015;25:35-42. doi: 10.1111/ipd.12095.
 Rosano A, Loha CA, Falvo R, Van Der Zee J, Ricciardi W, Guasticchi G, de Belvis AG.The relationship between avoidable hospitalisatin and accessibility to primary care: a systematic review.Eur J Pub Health 2012, 23(12):356-360.
 Zhao Y, Wright J, Guthridge S, Lawton P. The relationship between number of primary health care visits and hospitalisations: evidence from linked clinic and hospital data for remote Indigenous Australians. BMC Health Serv Res 2013, 13: 466 (online) http://www.biomedcentral.com/1472-6963/13/466
 Kruger E, Tennant M. Potentially preventable hospital separations related to oral health: a 10-year analysis. Australian Dental Journal 2015, 60: doi: 10.1111/adj.12322
 S Subramanian, K Smith, E Kruger, M Tennant. Hospitalization for oral malignancies in Western Australians: a four-year retrospective analysis. Asia–Pacific Journal of Clinical Oncology 2005; 1: 151–157
 Lyndon Paul Abreu, Estie Kruger, Marc Tennant. Oral cancer in Western Australia, 1982–2006: a retrospective epidemiological study. J Oral Pathol Med (2010) 39: 376–381.
 E. Kruger, K. Smith, M. Tennant: Jaw fractures in the indigenous and non- indigenous populations of Western Australia: 1999–2003. Int. J. Oral Maxillofac. Surg. 2006; 35: 658–662.