Australian Dental Journal

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1 Australian Dental Journal The official journal of the Australian Dental Association Australian Dental Journal 2018; 63: 4 13 doi: /adj Dental insurance, service use and health outcomes in Australia: a systematic review ES Gnanamanickam,* DN Teusner,* PG Arrow,* DS Brennan* *Australian Research Centre for Population Oral Health, Adelaide Dental School, The University of Adelaide, Adelaide, South Australia, Australia. Department of Health, Dental Health Services, Perth, Western Australia, Australia. ABSTRACT Private health insurance plays a key role in financing dental care in Australia. Having private dental insurance has been associated with higher levels of access to dental care, visiting for a check-up and receiving a favourable pattern of services. Associations with better oral health have also been reported. In the absence of any existing review, this paper aims to systematically review the relationship between dental insurance and dental service use and/or oral health outcomes in Australia. A systematic search of online databases and subsequent sifting resulted in 36 publications, 33 of which were cross sectional and three cohort analyses. Dental service outcomes were more commonly reported than oral health outcomes. There was considerable heterogeneity in the outcome measures reported, for both service use and health outcomes. Overall, the majority of the evidence was from cross sectional studies and few studies reported analyses adjusted for confounding factors. The consolidated evidence points towards a positive association between dental insurance and dental visiting. Dentally insured adults are likely to have more regular access to dental care and have a more favourable pattern of service use than the uninsured. However, evidence of associations between dental insurance and oral health are mixed. Keywords: Australia, dental insurance, dental service use, oral health outcomes, review. Abbreviations and acronyms: ARCPOH = Australian Research Centre for Population Oral Health; CAL = clinical attachment loss; CI = confidence interval; DMFS = decayed, missing, filled surfaces; DMFT = decayed, missing, filled teeth; HIE = RAND Health Insurance Experiment; NS = not significant; OHIP = oral health impact profile; OR = odds ratio; PD = pocket depth; PHI = private health insurance; PR = prevalence ratio; RR = rate ratio; SROH = self-reported oral health. (Accepted for publication 18 May 2017.) INTRODUCTION Private health insurance (PHI) plays a key role in the financing of dental care in the Australian health system. 1 In , 12% of all spending on dental services was funded indirectly by individuals via PHI. 2 The Australian PHI industry is highly regulated and is directly subsidized by the government via a meanstested 30% insurance premium tax rebate. Key regulations include community-rated premiums, control on premium increases and limits on the types of services that can be insured. Community-rated premiums support non-discriminatory access to PHI by ensuring that premiums are the same regardless of the health or demographic characteristics of the individual. Insurance cover for dental services is typically provided under general treatment cover which can be purchased separately or as part of a combined policy with hospital cover. In 2013/2014, approximately 55% of the population had general treatment cover, and the vast majority had dental cover. 3 Having PHI has been associated with higher levels of dental visiting, visiting for a check-up, and receiving a favourable pattern of services (visiting a dentist in the last 2 years, visiting the same dental professional regularly and visiting for a check-up). 4 Consistent with these, associations between PHI and better oral health have also been reported. Although regular dental visiting is not necessarily associated with lower disease experience, 5 regular care and usually visiting for a check-up have been associated with less untreated decay 6 and fewer social impacts of oral disease. 4,7 Dental insurance potentially influences dental visiting patterns by lowering the cost at the time of accessing care. While regular dental visiting has been associated with better oral health, it has been argued that PHI may induce additional use of services (moral Australian Dental Association

2 Dental insurance, service use and outcomes: A review hazard) that are of marginal or no benefit. 8 Higher levels of service use by the insured can also be explained by self-selection into insurance by those who have greater need for care or have a predisposition to seek care regularly (adverse self-selection and advantageous selection). Consequently, in observational studies self-selection can bias the effects of insurance on service use. 9 This type of bias can be reduced by experimental study designs, but so far there has been only one experimental insurance study, conducted in the USA in the 1980s. The RAND Health Insurance Experiment (HIE) was a large randomized controlled trial that found that the generosity of cover (level of copayments) was positively associated with the probability of dental visiting. The generosity of cover was also associated with variations in types of services received. Prosthodontic treatment was 62% higher among those with the most generous plan (0% copayment) compared with those who had the least generous plan (95% co-payment) while endodontic and periodontal treatment were 50% higher. 10 With respect to oral health outcomes, those with the most generous plan compared to those on less generous levels of cover had, less untreated decay, more filled teeth and lower periodontal index scores. The differences were greater for children and young adults (<35 years of age) than for older adults. 11 The findings of the RAND HIE are limited in their relevance to the current Australian policy context. The HIE plans provided protection from catastrophic costs via annual caps on total co-payments (out-ofpocket costs). Conversely, in Australia, the insurance plans typically have caps on benefits, providing limited protection from large dental costs. In addition, Australian plans typically provide lower levels of cover (~50% of claimed dental costs), than the more generous plans in the HIE that were associated with increased probability of visiting. Assessing the degree to which dental insurance improves access to dental care may indicate the potential for oral health improvements through public health policies that extend dental insurance coverage in the community. Alternatively, improvements in population oral health associated with PHI may also indicate the potential effectiveness of policies that aim to reduce out-of-pocket costs of dental services and/or provide public subsidization of dental care. While there have been numerous studies investigating the relationships between dental insurance, service use and health outcomes, only one review 12 that reported on 10 American publications was identified. Hence, the aim of this paper was to systematically review and collate all empirical evidence in Australia, which investigated the association between dental insurance and dental service use and/or oral health outcomes. METHODS A systematic search of all available published research in Australia that reported on the relationship between dental insurance and the two outcome categories dental service use and oral health outcomes was undertaken in 2015 and updated in early A comprehensive literature search was conducted in the online databases of the Cochrane Library, Dental and Oral Sciences Source, Embase, Medline, PubMed, Scopus and Web of Science. Only publications reporting data on human adults ( 18 years) and with fulltext accessible in the English language were included. The studies included were observational studies in Australia, reporting private dental health insurance, and one or both dental service use or oral health outcomes and their association with private dental insurance. The cut-off year of 1986 was used based on the publication year of the RAND HIE, the seminal study investigating this research question. A three-stage sifting process consisting of title sifting, abstract sifting and full-text perusal was employed to identify citations that were both relevant to the research question and that met the criteria. Additionally, the list of citations after the abstract sifting stage, were subjected to a search of references and citation tracking through Google Scholar and the Scopus database to identify additional publications and grey literature. Other grey literature was also identified by contacting two experts identified from the final list of publications. Finally, full papers were examined and evaluated. A descriptive and narrative synthesis 13 identified all relevant outcomes; results of each outcome and their measures (means, proportions, odds ratios (OR) and prevalence ratios (PR)) were collated. Where relevant, the measures were combined or reported as a range. Those without dental insurance were the reference group for all comparisons and ratios unless indicated otherwise. The quality assessment system employed in this review was adapted from the Agency for Healthcare Research and Quality at the US Department of Health and Human Services (Table 1). 14 RESULTS Figure 1 shows the filtering steps of the review process, and the resulting number of citations included at each stage. Four hundred and thirty-five citations were available for the review process. After the sifting process and identification of grey literature, 37 papers were assessed for quality Australian Dental Association 5

3 E Gnanamanickam et al. Table 1. Domains and elements assessed to determine study quality Domains Elements Essential (yes/no) Publication Peer reviewed journal article No Study question Clearly stated and appropriate Yes Study Description of study population Yes population Sample size justification No Sample sufficient size for analysis No Inclusion/exclusion criteria stated No Sample representativeness assessed No Outcome Primary outcomes clearly defined Yes measurement Outcome assessment standard, No valid and reliable Statistical Statistical tests appropriate Yes analysis Modelling and multiple variable No analysis conducted Controlled for potential No confounders (in relation to insurance status) Potential for selection bias assessed No (i.e. associated with self-selection into insurance) Discussion Conclusions, relating to insurance Yes associations, supported by results Biases and limitations taken into consideration No Adapted from the Agency for Healthcare Research and Quality. 14 Quality assessment A quality assessment was applied to 37 papers; only one paper 15 was excluded from the review based on failure to meet one of the essential quality criteria (conclusion relating to dental insurance associations not supported by the results). The majority of the papers (72%, N = 26) were published in peer-reviewed journals, mostly meeting the non-essential criteria except for sample size justification, controlling for confounding and accounting for bias associated with self-selection into insurance, that is, endogeneity of insurance. Descriptive synthesis The final data for the review consisted of 36 publications, 33 of which were cross sectional analyses and three cohort analyses. Supplementary material provides a descriptive summary of all the studies. Dental service outcomes were more commonly reported (N = 28) than oral health outcomes (N = 13), and five publications reported both service use and health outcomes. Narrative synthesis Dental service outcomes Service use outcomes The dental service use outcomes examined dental visiting measures and the type of services received or provided. The various dental visiting outcomes and their unadjusted and adjusted estimates are summarized in Table 2. All reported dental visiting outcomes except no visit in the last 2.5 years and visiting for a checkup (both reported in one study each) had a significant positive association with being insured. Service area outcomes Collated results for all service area outcome variables and their respective measures are presented in Table 3. All publications that reported outcomes by service areas, only reported it among those who visited. Preventive and extraction services were consistently significantly associated with being insured both in unadjusted and adjusted analyses; the insured receiving higher preventive services and lower extraction services. Oral health outcomes Oral health outcomes included clinical outcomes collected through a clinical examination, and self-reported outcomes collected by mailed or telephone surveys. Clinical outcomes The most common clinical oral health outcomes were related to caries and periodontal disease (Table 4a). Most clinical outcomes were reported in only one publication. Very few studies reported adjusted analyses, and the adjusted results were a mixture of significant and non-significant differences between the insured and uninsured. Self-reported outcomes The self-reported (by study participants) outcome measures varied across studies; only global selfreported oral health (SROH), toothache frequency, oral health impact profile (OHIP) severity and edentulism were reported by more than one publication (Table 4b). SROH, edentulism in older adults and two OHIP measures were significantly worse among those who were not dentally insured. DISCUSSION This review examines evidence from 36 publications that reported on the association between dental insurance and dental service use and/or oral health outcomes. Both groups of outcome variables service use and oral health were heterogeneous; that is, the outcome variables and measures were varied. The evidence for most outcome variables was reported in only single or few publications, and only three variables were reported in five or more publications Australian Dental Association

4 Dental insurance, service use and outcomes: A review Publications identified through database searches, n = 435 Excluded through title sifting, n = 359 Excluded through abstract sifting, n = 43 Total Publications identified for full paper review, n = 33 Publications identified from experts/grey literature, n = 6 Publications identified through citation tracking, n = 4 Publications identified through reference searching, n = 4 Excluded based on Full paper review, n = 10 (i.e., not meeting one or more criteria) Excluded based on quality assessment, n = 1 Publications included in final review, n = 36 Publications reporting on dental service use, n = 23 Publications reporting both dental service use and oral health outcomes, n = 5 Publications reporting on oral health outcomes, n = 8 Fig. 1 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart of review process Australian Dental Association 7

5 E Gnanamanickam et al. Table 2. Collated results, dental service use outcomes, dental visiting Dental visiting outcomes Unadjusted Adjusted Insured* Uninsured* Ratios Time since last visit In the last year (%) ,22,25 PR = 1.48, OR = 1.9, 2.6 In the last 2 years (%) 2 28, ,29 PR = 2.19 and 1.17 <12 months (%) years (%) >2 years (%) No visit in last 5 years (%) 2 21, OR = 2.3 No visit in last 2.5 years (%) NS No. dental visits (last 12 months) (mean) 3 24,26, Usual visiting pattern Once a year (%) 4 21,29,32, Once in 2 years (%) PR = 1.18 Favourable visiting pattern (combination of visiting, check-up visit and regular dentist) Favourable (%) 2 3, PR = 1.82, 1.95 Intermediate (%) Unfavourable (%) Reason for visit Relief of pain (%) 2 25, Check-up (%) 7 23,30,31, PR = NS 1 18 Problem (%) 4 28,30,33, ,33 OR = 0.65 RR = 1.7* Sector of visiting at last visit Private (%) 3 30,31, Public (%) Regular dentist (%) 2 31, *% insured or uninsured reported as a range if outcome reported in more than one publication. Ratios were either odds ratios (OR), prevalence ratios (PR) or rate ratios (RR) of the insured group relative to the uninsured. Statistically significant difference. Differences between insured and uninsured not statistically tested. Ratios where the insured group were the reference category. NS = not significant. The consolidated evidence points towards a positive association between dental insurance and dental visiting. In the literature, visiting a dentist in the last 2 years, visiting the same dental professional regularly and visiting for a check-up are considered to be favourable or beneficial patterns of dental visiting. 4 There was a positive association between all three outcomes and being dentally insured. Associations between insurance and service level outcomes also suggested a favourable pattern of service use for those with dental insurance. Insured adults were more likely to receive diagnostic, preventive (including only scale and cleans), dentures, and crown and bridge services, and less likely to receive extraction services. Consolidated unadjusted evidence for oral health outcomes suggests that dental insurance has some favourable associations with both clinical and selfreported oral health outcomes. While unadjusted differences in outcomes between the insured and uninsured provide a descriptive understanding of the associations, they fail to take into consideration other factors that potentially attenuate or strengthen the association. Only approximately two-thirds of the publications reported adjusted analyses. Most insurance effects observed for the dental visiting and service level variables were largely unaltered in the adjusted analyses. However, for health outcomes the collated adjusted results were mixed. After adjusting for other explanatory variables, the association between insurance and global self-rated oral health remained significant, but it was not significant for untreated decay and other caries measures. Two of the three OHIP measures reported in the adjusted analyses were significant. With the exception of dentate status, adjusted estimates for other self-reported measures were either not reported or not significant Australian Dental Association

6 Table 3. Collated results, dental service use outcomes, services received/provided Dental insurance, service use and outcomes: A review Dental service received/provided Unadjusted Adjusted Insured* Uninsured* Ratios % Who received services (among those who visited in the last 12 months) Fillings (%) , Restorative (%) 1 38 NS Extractions (%) 5 18,23,24,36, OR = 0.50 Scale and cleans (%) Preventive (%) 1 38 OR = 1.42 Diagnostic (%) 1 38 NS Root canal (%) Endodontic (%) 1 38 OR = 1.52 Crowns and bridges (%) OR = 1.94 Gum treatment (%) Dentures (%) Mean services received among those who visited in the last 12 months Fillings (mean) Extractions (mean) Scale and cleans (mean) Per cent of persons receiving services per visit Diagnostic (%) NS Preventive (%) OR = 1.37 Extraction (%) OR = 0.52 Restorative (%) NS Crown and bridge (%) OR = 2.25 Endodontic (%) OR = 1.27 Prosthodontic (%) NS Mean services per visit Total (mean) Diagnostic (mean) NS Examination (mean) NS Radiograph (mean) NS Preventive (mean) RR = 1.27 Prophylaxis (mean) NS Topical fluoride (mean) NS Extraction (mean) 2 40, , , RR = 0.50 and NS Restorative (mean) , , ,41 NS Crown and bridge (mean) NS Endodontic (mean) 2 40, , , ,41 NS Prosthodontic (mean) NS General (mean) NS Results from one publication 39 excluded in the adjusted analysis used different sub categorisations of insurance status. *Per cent insured or uninsured reported as a range if outcome reported in more than one publication. Ratios were either odds ratios (OR), prevalence ratios (PR) or rate ratios (RR) of the insured group relative to the uninsured. Statistically significant difference. NS = not significant. Hence, the available evidence for the association between oral health outcomes and dental insurance is mixed and limited. Quality, strength of evidence and selection bias All papers reported on observational studies. While observational studies are not accepted as the highest level of research evidence, overall the quality of the publications in the review was considered good. The viability of conducting experimental studies in health insurance research is very low, as evidenced by the fact that there has only been one randomized controlled trial which explored the effects of health insurance on health service use. 10 The majority of the papers were published in peer-reviewed journals. Only one paper was excluded after quality assessment. Limitations While there are similarities between Australia and other countries in terms of dental financing arrangements, the regulatory framework of the Australian PHI market is unique. The generalizability of these findings to other countries may be limited. Similarly, significant changes in future policy on health insurance and dental service delivery may also affect the application of these results in Australia. The conclusions drawn from a review of existing evidence are only as valid as the evidence they summarize. Hence, all limitations that affect the original studies reported in the reviewed publications remain. Additionally, the collated results are limited by the variability in the data in terms of age, gender, geographical locations and sampling frames Australian Dental Association 9

7 E Gnanamanickam et al. Table 4a. Collated results, oral health outcomes, clinically measured Clinically measured outcomes Unadjusted Adjusted Insured* Uninsured* Significance Decayed tooth (mean) S Missing tooth (mean) S Filled tooth (mean) S DMFT (mean) 1, , , NS Missing teeth due to pathology (%) Decayed teeth (%) 4 30,34,43, NS No decay (%) One or more filled teeth (%) Missing tooth due to caries (%) DMFS (mean) Decayed surfaces (mean) Precavitated decayed surfaces (mean) NS Carious lesion severity among those diagnosed with caries Initial lesions (%) Cavitated lesions (%) Gross lesions (%) Periodontal disease measures Periodontal disease (%) >4 mm periodontal pocket depth (%) 2 30, Clinical attachment loss of >4 mm (%) *Per cent or mean insured or uninsured reported as a range if outcome reported in more than one publication. Ratios not reported in original studies. Statistically significant difference. DMFS = decayed, missing, filled surfaces; NS = not significant; S = significant. Table 4b. Collated results, oral health outcomes, self reported Self-reported outcomes Unadjusted Adjusted Insured* Uninsured* Ratios Self-rated oral health: good/very good/excellent (%) 3 34,37, PR = 1.20 and 1.38 Dentate status: <21 natural teeth (%) Edentulism (adults) (%) Edentulism (older adults) (%) OR = 0.50 Missing teeth (mean) OHIP Severity (mean) 2 48, Prevalence (%) Counts (mean) Scale scores (mean) Perceived need for treatment Extractions/fillings (%) Urgent treatment (%) Toothache: very often/often/sometimes (%) 3 34,37, NS Orofacial pain (%) Dissatisfied appearance (%) NS Food avoidance (%) NS Combined measures of toothache and mouth and denture problems Never/hardly ever (%) Ref. Sometimes (%) NS Often/very often (%) NS Combined measure of toothache, food avoidance and discomfort due to mouth appearance Any of the three (%) NS All of the three (%) NS *Per cent or mean insured or uninsured reported as a range if outcome reported in more than one publication. Ratios were either odds ratios (OR), prevalence ratios (PR) or rate ratios (RR) of the insured group relative to the uninsured. Statistically significant difference. Ratios where the insured group were the reference category. Significant beta estimates. NS = not significant; OHIP = oral health impact profile Australian Dental Association

8 Dental insurance, service use and outcomes: A review As evident from the collated results, the number of publications reporting adjusted analysis was low. Hence this review did not examine the types of variables used in the publications, to control for the effect of the relationship between dental insurance and the outcomes. Public health implications At a health system level, there is evidence that PHI policies are regressive in nature and have potentially increased inequity in access. 16,17 In addition, the exclusionary nature and low annual claim limits of dental insurance in Australia do not protect individuals from large and potentially catastrophic dental costs associated with dental care that are necessary for the maintenance of a functional dentition. While this review found statistically significant associations between having dental insurance and favourable patterns of dental service use and some associations with good oral health, these findings do not necessarily support private insurance or existing policies aimed at subsidizing PHI. Alternative insurance systems, such as public insurance or social insurance that are purposefully structured to address cost and equity issues, may achieve both better access to care and equity. Areas for future research/gaps in literature As noted earlier, dental service use variables were more commonly reported than oral health outcomes. Even among the publications that reported health outcomes, very few outcomes were reported in more than one publication, and all of them reported from cross sectional data. Notably, there were no publications examining associations between insurance status and treatment decisions or follow-up compliance by patients, and few publications on chronic oral health conditions, perceived need for care and quality of life outcomes. Multiple publications in the review reported analyses of data from single or multiple waves of the same study but focussed on different outcomes, subsamples and/or employed different analytical methods. Evidence derived from other data sources collected via different methods would broaden and strengthen the evidence base. Study designs in this review were predominantly cross sectional, and three publications reported on short-duration cohort studies. More cohort studies of longer duration would contribute to extending the evidence base. If insurance was found to be effective, the cost-effectiveness of insurance would need to be ascertained to inform future policy. CONCLUSIONS The available evidence in Australia suggests that dentally insured adults are more likely to have more regular dental care and have a favourable pattern of service use than uninsured. However, associations between dental insurance and oral health are less clear. The results were mixed, and there was a paucity of studies reporting adjusted analyses. However, the studies reviewed broadly reflected the associations usually found between regular care and oral health; that is, dental insurance was not associated with less disease experience but was associated with bettermanaged disease (less untreated decay and more filled teeth). ACKNOWLEDGEMENTS Author contribution was as follows: the first author developed the search strategy and criteria with input from the co-authors; the database searching, retrieving and sifting of titles and abstracts were independently performed by the first author and the quality assessment was conducted by the second author; all papers in the final list of search results were independently read and data was extracted into a table developed by the first and second author; synthesis of results and drafting of manuscript was performed by the first author with substantial input from the co-authors and discussion of results was contributed to by all authors. The authors acknowledge the editorial contributions of the peer reviewers. The study was undertaken as part of a PhD that was financially supported by a National Health and Medical Research Council Centre for Research Excellence Grant in Health Services (no ) and supervised with support from a Career Development Award (no ). The contents are solely the responsibility of the administering institution and authors, and do not reflect the views of the National Health and Medical Research Council. SUPPORTING INFORMATION Additional Supporting Information may be found in the online version of this article: Table S1. Year of study, authors, year of publication, samples and service use outcome measures of reviewed publications. Table S2. Year of study, authors, year of publication, samples and oral health outcome measures of reviewed publications. REFERENCES 1. Paris V, Devaux M, Wei L. Health Systems Institutional Characteristics: A Survey of 29 OECD Countries. OECD Health 2017 Australian Dental Association 11

9 E Gnanamanickam et al. Working Papers, No 50, OECD Publishing [Internet]. 2010; No. 50 Available at: org/toolkits/public-policy-toolkit/upload/oecd-survey.pdf. Accessed 23rd February AIHW. Health expenditure Australia Canberra: AIHW, Teusner D, Brennan D, Spencer A. Associations between level of private dental insurance cover and favourable dental visiting by household income. Aust Dent J 2015;60(4): Crocombe LA, Broadbent JM, Thomson WM, Brennan DS, Poulton R. Impact of dental visiting trajectory patterns on clinical oral health and oral health-related quality of life. J Public Health Dent 2012;72: Sheiham A, Maizels J, Cushing A, Holmes J. Dental attendance and dental status. Community Dent Oral Epidemiol 1985;13: Brennan D, Spencer A, Roberts-Thomson K. Caries experience among year olds in Adelaide, South Australia. Aust Dent J 2007;52: Harford J, Spencer AJ. Oral health perceptions. In: Slade G, Spencer AJ, Roberts- TK, eds. 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North Carolina: Agency for Healthcare Research and Quality, US Department of Health and Human Services; Gablinger Y, Savage E, Hall J. An Assessment of the Effect of the Private Health Insurance Incentives Scheme on Dental Visits Available at: rence/download.cgi?db_name=esam06&paper_id=254. Accessed 23 February Fitzgerald EM, Cunich M, Clarke PM. Changes in inequalities of access to dental care in Australia Aust Econ Rev 2011;44: Harford J, Spencer AJ. Government subsidies for dental care in Australia. Aust N Z J Public Health 2004;28: AIHW Dental Statistics and Research Unit. Dental Insurance and Access to Dental Care. Adelaide: The University of Adelaide, Contract No.: Research Report No Slack-Smith L, Hyndman J. The relationship between demographic and health-related factors on dental service attendance by older Australians. Br Dent J 2004;197: Slack-Smith LM, Mills CR, Bulsara MK, O Grady MJ. 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10 Dental insurance, service use and outcomes: A review 45. Roberts-Thomson K, Stewart JF. Risk indicators of caries experience among young adults. Aust Dent J 2008;53: Teusner DN, Anikeeva O, Brennan DS. Self-rated dental health and dental insurance: modification by household income. Health Qual Life Outcomes 2014;12: Ringland C, Taylor L, Bell J, Lim K. Demographic and socioeconomic factors associated with dental health among older people in NSW. Aust N Z J Public Health 2004;28: Brennan DS, Spencer AJ. Comparison of a generic and a specific measure of oral health related quality of life. Community Dent Health 2005;22: Sanders AE, Slade GD, Sungwoo L, Reisine ST. Impact of oral disease on quality of life in the US and Australian populations. Community Dent Oral Epidemiol 2009;37: Jamieson LM, Mejıa GC, Slade GD, Roberts-Thomson KF. Risk factors for impaired oral health among 18- to 34-year-old Australians. J Public Health Dent 2010;70: Address for correspondence: Dr Emmanuel Gnanamanickam Australian Research Centre for Population Oral Health (ARCPOH) Adelaide Dental School The University of Adelaide Level 9, Adelaide Health and Medical Sciences Building Adelaide, SA 5001 Australia emmanuel.gnanamanickam@adelaide.edu.au; emmanuel.gnanamanickam@flinders.edu.au 2017 Australian Dental Association 13