Globally, of the 50 most prevalent chronic diseases, four are related to oral health: (1) dental caries of permanent teeth, (2) chronic periodontitis, (3) dental caries of deciduous teeth and (4) edentulousness (total tooth loss) [
1,
2]. Tooth loss is predominantly a consequence of dental caries in the permanent dentition and adult chronic periodontitis, and potentially results in substantial social and health consequences. Dental caries in the deciduous dentition is a significant predictor of dental caries in the permanent dentition [
3]. With few exceptions, both dental caries and periodontitis are preventable conditions with adequate self-care and healthy lifestyle habits, with additional health promotion and preventive interventions at the health services level [
4,
5]. However we continue to struggle to significantly reduce, and preferably eradicate, the burden of preventable oral health conditions. Appropriate self-care is largely dependent on the social and health capital of the community [
6]. In disadvantaged, marginalised, rural and Indigenous communities, this is often absent. These communities also have the additional burden of limited health promotion and preventive services, carry a significant health burden and suffer a seriously reduced oral health-related, and overall quality of life [
7,
8].
Most dental health promotion and preventive services require professionally trained personnel, needing equipment and regular availability of the service for the re-application of interventions. The current evidence is that a number of dental preventive interventions require re-application 2 to 4 times a year [
9,
10]; and in disadvantaged and especially remote communities, this is usually not possible, and the burden of the common oral diseases is never dealt with: more importantly, never prevented. To our knowledge there is currently no evidence on the effectiveness, cost-effectiveness and cost-benefit of a less frequent and therefore sustainable dental preventive intervention strategy.
The proposed study will implement a novel dental caries preventive intervention in children to firstly reduce the pathologic bacterial load using an oral anti-septic, secondly seal the part of the tooth most prone to decay with a fissure sealant, and thirdly to strengthen the tooth structure with a fluoride varnish, all during a single annual visit, in a rural remote Indigenous community in Far North Queensland, Australia. While there are data on the effectiveness of the three specific interventions, we have developed a novel approach to assess a less frequent combined application of these interventions. Importantly, we will assess its effectiveness and its cost effectiveness to determine the value for money of the service.
The team believes that the current suggested frequency 2–4 times per year for these preventive interventions is not possible, or sustainable, in poorly-resourced, remote communities and is proposing an alternative strategy requiring fewer resources to address the burden of dental decay in children.
Burden of dental caries in Indigenous communities in Australia
In Australia, dental conditions are especially prevalent in Indigenous communities, and are a significant health burden in rural remote communities [
7,
8]. A recent report of the dental caries status of Indigenous children in Australia showed that those located in rural and/or remote areas have a much higher mean number of decayed, missing and filled deciduous teeth (dmft) (~4 in 6-year old children) compared to non-Indigenous children in metropolitan (dmft ~ 1.5) and rural settings (dmft ~ 1.8) as well as Indigenous metropolitan children (dmft ~ 2.6) [
11]. The situation is similar in the permanent dentition of older children. The National Survey of Adult Oral Health found that 57 % of Indigenous adults had untreated coronal dental caries, compared with 25 % of non-Indigenous adults [
12]. The mean number of decayed teeth amongst Indigenous adults (>15 years of age) was 2.7 compared to 0.8 amongst non-Indigenous adults.
There are high social costs associated with poor dentition, and a diminished quality of life due to pain and discomfort [
13‐
16], and especially because of long waiting lists for treatment [
17]. Social costs include lack of sleep, lost time for school, behavioural problems, lack of cooperation and diminished learning. Lost working time for parents accompanying children to dental treatment sessions has been reported to lead to a loss of employment. Studies in this area need to appreciate the full impact of childhood caries on the child, family and society.
An oral health survey in 2004 (pre-water fluoridation) in the Northern Peninsula Area (NPA) of far north QLD, found that dental caries experience of 6- and 12-year-old children was more than twice that of the state average and more than four times greater than the comparable figures for Australian children overall. Soon after this survey the reticulated water supply of the five small rural communities in this area was fluoridated. A follow-up oral health survey in NPA conducted in November 2012 by this team, in which we examined over 70 % of known resident schoolchildren (
n = 339), suggests that the dental caries status has improved significantly since the 2004 survey [
18]. Few teeth had restorations in both surveys. Age-weighted overall caries prevalence and severity declined from 2004 to 2012 by 37.3 %. The effect was most marked in younger children, dmft decreasing by approximately 50 % for ages 4 to 9 years; at age six, mean decayed score decreased from 5.20 to 3.43. DMFT levels decreased by half in 6 to 9 year old children. However, significant unmet treatment needs exist at all ages. To address this, practical and affordable ways have to be found.
One of the reasons for the improved oral health status could be due to fluoridation of the local water supplies. Whilst the economic viability of water fluoridation for a small community such as this might be questioned, we posit the costs are outweighed by the significant caries reduction in both the deciduous and permanent dentitions as found in our study [
18]. Moreover, the fluoridation plant has functioned erratically since being implemented and has been out of operation since April 2011 following a lightning strike. The likelihood that the water will again be fluoridated is uncertain due to budget constraints and because the 2012–2015 Queensland State Government legislated to give local governments across the State the power to decide to fluoridate or not. Dental caries rates may again increase in the absence of water fluoridation. It will be crucial to investigate alternative models to ensure improvements in dental caries incidence in this resource-constrained community. The envisaged dental prevention model will essentially reduce the microbial load with the topical disinfectant, povidone iodine [
10]; inhibit biofilm adherence to susceptible sites by application of fissure sealants [
19] and reduce the susceptibility of the tooth to demineralisation by acids generated in the microbial biofilm by the application of a fluoride varnish [
9,
20]. Measures of local fluoride concentration [
20] and of oral mutans streptococci counts return to baseline after a few months [
21], so that most reported studies have used regular re-applications (2–4 times per annum), which would be difficult to implement in remote settings lacking appropriately trained personnel and resources. Fissure sealants, on the other hand, have excellent longevity [
19].
To date, the reported economic burden of childhood caries is likely to be underestimated, as previous reports did not capture the full scope of costs and missed the potential cost-savings of prevention programs. There are few studies involving child populations that evaluate the cost-effectiveness of prevention programs for childhood caries [
22]. Savage et al. [
23] concluded that pre-school aged children in the USA who had early dental prevention visits would experience lower dental-related costs over 5 years. Similarly, a second USA study by Ramoz-Gomez et al. [
24] looked at minimal, intermediate and comprehensive prevention programs and concluded that all three were cost-effective. They concluded that government health systems can save considerable resources by investing in early childhood caries prevention. A study by Lee et al. [
25] in Carolina, USA, found early dental visits were highly cost-effective for high-risk children. These studies reiterate the need for translating this evidence into policies for childhood caries prevention. Although the cost-savings of prevention programs are based on predictions, the potential economic benefits are encouraging.
Aims and hypotheses
The study seeks to (1) assess the effectiveness of an annual oral health preventive intervention in slowing the incidence of dental caries in children in a remote, rural Indigenous setting, (2) identify the mediating role of known risk factors for dental caries and (3) assess the cost-effectiveness and cost-benefit of the intervention.
We hypothesise that 1 and 2 years after the intervention (1) the actual incidence of dental caries in children will be significantly lower than the expected incidence, based on modelling from the two oral health surveys conducted over the past 11 years in the same community, the current survey and (2) the intervention will be cost-effective and cost beneficial, and therefore feasible and sustainable for broader implementation across similar communities in Australia and internationally.