International Dental Journal 2015; 65: 39–44
SCEINTIFIC RESEARCH REPORT
doi: 10.1111/idj.12141
Trends in dental service provision in Australia: 1983–1984 to 2009–2010 David S. Brennan, Madhan Balasubramanian and A. John Spencer Australian Research Centre for Population Oral Health, Faculty of Health Sciences, School of Dentistry, The University of Adelaide, Adelaide, SA, Australia.
Objective: To investigate time trends in dental service provision. Methods: A random sample of Australian dentists was surveyed by mailed questionnaires in 1983–1984, 1993–1994, 2003–2004, and 2009–2010 (response rates 67–76%). The service rate per visit was collected from a log of services. Results: The rate of service provision per visit [rate ratio (RR)] increased from 1983–1984 to 2009–2010 for the service areas of diagnostic (RR = 1.8; 1.6–1.9), preventive (RR = 1.9; 1.6–2.1), endodontic (RR = 2.1; 1.7–2.6), and crown and bridge (RR = 2.9; 2.3–3.8), whereas prosthodontic services decreased (RR = 0.7; 0.6–0.9). Conclusions: The profile of services provided by dentists changed over the study period to include less emphasis on replacement of teeth and more on diagnosis, prevention, and retention of natural dentitions. Key words: Private general practice, dental service provision, time trends
INTRODUCTION The dental workforce in Australia comprises mainly dentists (75.6%), with smaller numbers of dental therapists, dental prosthetists, dental hygienists, and oral health therapists1. Among Australian dentists, 79.7% of those in clinical work are in private practice, with general dental practice (73.3%) being the most common area of employment1. The majority of dentists working in Australia are from major cities (79.7%). The pattern of services provided by the dental workforce is of fundamental interest as this is expected to impact on the oral health of the population. A range of factors may influence service patterns, such as the characteristics of the providers (e.g. age and sex). Changes in patterns of oral health and population demographics are also considered to be important sources of potential influence on dental practice that could flow on to changes in rates of provision of dental services. Some key indicators of oral health have demonstrated improvements for the Australian population. Among children, 30-year trends in oral health have shown a marked decline in caries in the permanent dentition of 12-year-old children, although less so in the deciduous dentition of 6-year-old children2. For © 2014 FDI World Dental Federation
adults in Australia there has also been a marked decline in edentulism3–5, but untreated caries was prevalent among approximately one-quarter of adults6. Although increased retention of teeth is considered a major oral epidemiological trend in Australia, there is also an important demographic trend towards an ageing population. Population ageing is common to many developed countries owing to sustained low fertility and increasing life expectancy; as a result, the number and proportion of older people in the Australian population is increasing7. The pattern of dental services in Australia has characteristically shown a predominance of restorative, diagnostic, and preventive service areas, with trends over time reflecting the retention and maintenance of natural teeth8–11. In the UK, reductions in extractions and prosthodontics and increases in diagnostic, preventive, and restorative care were reported for the period 1965–198112. From 1999 to 2005, increased demand for dental care (apart from complete dentures) was reported for older people in the UK13. In the USA, diagnostic and preventive services have been reported to comprise the bulk of dental services14. There is evidence for improvements in oral health, reflected in changes in service patterns over time from 1980 to 199515, whilst prosthodontic services 39
Brennan et al. decreased, and the use of implants increased, from 1992 to 2007 within a population of insured patients in the USA16. Patterns of oral health care are predicted to undergo major changes linked to improved oral health, advances in treatment approaches, and populations that are ageing17. Such changes may be expected to be reflected in changes in the services provided by dentists. Characteristics of the dental workforce, such as the age and sex of dental providers, may also be related to services provided, and hence need to be controlled for when examining trends in service provision. The aim of this study was to investigate trends in service provision for Australian private general dental practitioners by comparing measures of services per visit at four time points across the period spanning 1983–1984 to 2009–2010, controlling for the dentist characteristics of age and sex. METHODS
practice. The number of patients sampled by each dentist varied according to their typical level of activity. Dentists were free to choose which days to include in their service log. Only dentists in the study sample within any group practice provided data. Dentists were instructed to record the services provided for each patient they treated on their selected typical days, regardless of whether or how they were charged to the patient. A patient may receive a number of services per visit across the range of 10 main areas of service, following the Australian Dental Association’s Schedule of Dental Services. Extraction services reported in this paper correspond to the area listed as oral surgery in this schedule. In this paper, findings are not presented for general/miscellaneous, periodontic, or orthodontic services, as the focus is on dental service provision in general practice dentistry and these service areas are provided at low rates in private general practice. The rate of services per visit was produced by dividing counts of services provided by the number of visits.
Sample and response
Analysis
A sample of 10% male dentists and 40% female dentists was randomly drawn from the dental registers for each State and Territory in Australia in 1983–1984. The higher sampling rate for female dentists was designed to include sufficient numbers for comparisons according to sex of dentist, as female dentists comprise a lower percentage of registered dentists than do male dentists. Sample supplementation at each successive wave of the study, based on 10% of male and 40% of female dentists who were newly registered since the previous wave, ensured representative cross-sectional estimates. In 1983–1984, 1988–1989, 1993–1994, 1998–1999, 2003–2004, and 2009–2010, these samples were surveyed by mailed questionnaire. For this analysis, data are presented for the surveys from 1983–1984, 1993–1994, 2003–2004, and 2009–2010, in order to capture parsimoniously the major trends across the period. The data were weighted using the estimated number of practising private general practice dentists at December 198318 with the age and sex distribution of dentists from the 1981 population census of Australia19 and dental board registration statistics from 199220, 199421 and 200022, and 200923. Therefore, the estimates of practice activity are representative of the age and sex distribution of Australian private practice dentists around each time.
Tests of statistical significance used in this analysis were based on the weighted sample data. Statistical comparisons were performed using Poisson regression for service rates per visit with P < 0.05 as the significance level. Adjusted models of service provision were constructed using indicator variables for the independent variables coded as 1 or 0, with a reference category not entered in the models.
Service provision data Dental practitioners recorded the types of services provided over one to two self-selected typical days of 40
Ethical review The study was approved by the Ethics Committee of the Australian Institute of Health and Welfare (AIHW), and was conducted in accordance with the Declaration of Helsinki. The study was conducted as a mailed self-complete survey; hence, consent was implied through the return of completed surveys. RESULTS The response rates obtained were 73% in 1983–1984, 74% in 1993–1994, 76% in 2003–2004, and 67% in 2009–2010. Services per visit are presented in Figure 1. This shows that services across the study period were provided at higher rates for restorative, diagnostic, and preventive services compared with endodontic, crown and bridge, prosthodontic, and extraction services. Rates of restorative services tended to be stable over the study period. Increased rates of service per visit over the time of the study were observed for diagnostic, preventive, endodontic, and crown and bridge services. Prosthodontic services © 2014 FDI World Dental Federation
Trends in Australian dental services
Figure 1. Services per visit according to time of study.
Table 1 Bivariate associations of service rates per visit according to sex and age of dentist Restorative Sex of dentist Male Female Age of dentist 20–29 years 30–39 years 40–49 years 50–59 years 60+ years
0.64 (0.01) 0.63 (0.01) 0.63 0.67 0.62 0.60 0.68
(0.02) (0.02) (0.02) (0.02) (0.05)
Diagnostic
Preventive
Endodontic
Crown and bridge
** 0.70 (0.01) 0.84 (0.02) ** 0.80 (0.03) 0.77 (0.02) 0.76 (0.02) 0.67 (0.02) 0.60 (0.03)
** 0.39 (0.01) 0.49 (0.02) ** 0.39 (0.02) 0.45 (0.02) 0.45 (0.02) 0.40 (0.02) 0.29 (0.03)
0.11 (0.01) 0.11 (0.01) ** 0.15 (0.01) 0.11 (0.01) 0.10 (0.01) 0.10 (0.01) 0.08 (0.02)
** 0.09 (0.01) 0.06 (0.004) ** 0.06 (0.01) 0.08 (0.01) 0.10 (0.01) 0.08 (0.01) 0.07 (0.01)
Prosthodontic ** 0.09 (0.01) 0.07 (0.01) ** 0.08 (0.01) 0.08 (0.01) 0.08 (0.01) 0.10 (0.01) 0.11 (0.02)
Extraction 0.09 (0.004) 0.08 (0.004) ** 0.09 (0.01) 0.09 (0.01) 0.07 (0.01) 0.09 (0.01) 0.11 (0.01)
**P < 0.01.
Table 2 Adjusted associations of service rates per visit according to sex and age of dentist and to time of study Restorative Sex of dentist Male Female Age of dentist 20–29 years 30–39 years 40–49 years 50–59 years 60+ years Time of study 1983–1984 1993–1994 2003–2004 2009–2010
1.0 (0.9– 1.1) Ref. 1.1 1.0 1.0 1.0
Ref. (1.0–1.2) (0.9–1.1) (0.9–1.1) (0.9–1.2)
Ref. 1.0 (1.0–1.1) 1.1 (1.0–1.1) 1.0 (0.9–1.1)
Diagnostic
Preventive
Endodontic
1.0 (0.9–1.0) Ref.
0.9 (0.8–1.0) Ref.
1.1 (1.0–1.3) Ref.
1.0 0.9 0.8 0.7
Ref. (0.9–1.1) (0.9–1.0) (0.8–0.9)** (0.7–0.8)**
Ref. 1.2 (1.1–1.3)** 1.7 (1.5–1.8)** 1.8 (1.6–1.9)**
1.2 1.1 1.0 0.7
Ref. (1.0–1.3)* (1.0–1.3) (0.9–1.2) (0.6–0.8)**
Ref. 1.3 (1.1–1.4)** 1.6 (1.4–1.8)** 1.9 (1.6–2.1)**
0.7 0.6 0.6 0.4
Ref. (0.6–0.9)** (0.5–0.8)** (0.5–0.8)** (0.3–0.5)**
Ref. 2.1 (1.7–2.6)** 2.4 (1.9–2.9)** 2.1 (1.7–2.6)**
Crown and bridge 1.6 (1.3–1.9)** Ref. 1.3 1.3 1.1 1.0
Ref. (1.0–1.7)* (1.0–1.7)* (0.8–1.4) (0.7–1.3)
Ref. 1.9 (1.5–2.5)** 2.2 (1.7–2.9)** 2.9 (2.3–3.8)**
Prosthodontic 1.1 (0.9–1.3) Ref. 0.9 1.0 1.0 1.4
Ref. (0.8–1.2) (0.8–1.2) (0.9–1.5) (1.1–1.8)
Ref. 1.0 (0.8–1.1) 0.8 (0.6–1.0)* 0.7 (0.6–0.9)**
Extraction 1.0 (0.9–1.2) Ref. 0.9 0.7 0.9 1.1
Ref. (0.7–1.1) (0.6–0.9)** (0.7–1.1) (0.9–1.3)
Ref. 1.0 (0.8–1.1) 0.8 (0.7–1.0)* 1.0 (0.8–1.2)
Values are given as rate ratio (95% confidence interval). Ref, reference category. *P < 0.05, **P < 0.01.
decreased over the time of the study. There was no clear trend in extraction services. Bivariate associations of sex and age of dentist with rates of service per visit are presented in Table 1. Female dentists provided higher rates per visit of diagnostic and preventive services, whereas male dentists © 2014 FDI World Dental Federation
had higher rates of crown and bridge and prosthodontic services. Older dentists tended to have lower rates of diagnostic, preventive and endodontic services, but had higher rates of prosthodontic and extraction services. Crown and bridge services were highest among middle-aged dentists. 41
Brennan et al. In adjusted models of service rates, male dentists had a higher rate of crown and bridge services than did female dentists (Table 2). Statistically significant variation according to age of dentist was observed for diagnostic, preventive, endodontic, crown and bridge, and extraction services. Consistent increases over time were observed for diagnostic, preventive, and crown and bridge services. Whilst endodontic services were higher than baseline at each subsequent time point, the rate peaked in 2003–2004. Prosthodontic services decreased over the time periods spanning 2003–2004 and 2009–2010. Extraction services were provided at lower rates than the baseline in 2003–2004, but not in 1993–1994 or 2009–2010. DISCUSSION These findings are from a national survey based on a random sample from a comprehensive sampling frame with adequate response rates (in the vicinity of 70%), restricted to private general practitioners who comprise the majority of dentists in Australia, weighted to reflect the age and sex distribution of private general practitioners in Australia. Hence, it is likely that the results can be generalised to represent the Australian context. The use of service data from a self-selected typical day could potentially introduce bias, but it has been shown there was no significant difference in service rates in all 10 main areas of service between data collected over a 10-day sampling period compared with estimates based on one typical day nominated from the 10-day sampling period by the responding dentists24. The distribution of services was consistently dominated by restorative, diagnostic, and preventive services. The major trends over time in the rate of services per visit provided by a dentist included increases in diagnostic, preventive, endodontic, and crown and bridge services. This was consistent with improved oral health and retention of teeth through routine maintenance care and avoidance of extraction. Rates of service provision have followed the trends that were evident from previous reports10, for instance, increases in routine scheduled care such as diagnostic and preventive services, as well as interventions consistent with maintenance of a functional dentition such as endodontic and crown and bridge services. The overall mix of services is expected to continue to shift towards diagnostic and preventive services25, with the focus of preventive dentistry likely to include increasing numbers of older adults26. Anticipated major declines in restorative services related to caries were not apparent between 1993 and 1999 in the USA17. This was consistent with the findings from Australia presented here, although there has been a shift in restorative treatment away from 42
amalgams to composite materials27. Restorative treatment was the predominant treatment for caries, regardless of lesion severity28. However, between 1999 and 2009, preventive procedures generally increased, while surgical-type procedures decreased, for working-age adults in the USA29. For older adults in the USA, the observed increase in preventive services, and the decline in restorative and endodontic services, was considered to have access and workforce implications and a possible expanded role for dental hygienists30. Although provision of dental services is shaped by oral health status31, a number of factors may influence treatment choices32. Provision of dental services may reflect a range of dentist, patient and visit factors33,34, geographical location factors35,36, and system factors37. In this study there was little difference in the rates of provision of services between male and female dentists when adjusted for age and time period. However, differences according to age of dentist were apparent, with lower diagnostic and preventive services observed among older dentists, possibly reflecting differences in the age profiles of their patients. The higher rate of provision of endodontic services in younger dentists could potentially reflect trends in dental education, resulting in younger cohorts of dentists being more likely to pursue endodontic treatment38. Crown and bridge rates were higher in middle-aged dentists, possibly reflecting the age profile of their patients. These findings relate to the private sector, comprising the majority of Australian dentists, and may differ from public care. Dental services in the public sector in Australia are provided to socio-economically disadvantaged persons who face barriers to accessing dental care in the private sector. The pattern of dental services received at public clinics has more emphasis on extraction of teeth and less emphasis on preventive and maintenance care39. Further research on trends in provision of public dental care is required to verify if similar changes are occurring for public patients. The general trend towards increases over time in some service areas, such as diagnostic and preventive, and stability in other areas of service, are consistent with reported increases over time in the total number of services per visit11. The increased number of services per visit over time has been linked to decreased numbers of patient visits reported by dentists over this time period40. The decline in numbers of missing teeth among adults could increase the pool of teeth at risk of oral diseases41, and, coupled with demographic trends, result in a shift towards adults with complex treatment needs42. However, on average, there appears to have been no change in the aggregate provision of services per year by dentists11. The stability in annual services per dentist reflects a counterbalance © 2014 FDI World Dental Federation
Trends in Australian dental services of a trend to supply fewer visits but to provide more services at each visit. Younger cohorts are providing fewer patient visits each working year, and this work pattern appears to be relatively stable over time as they move into middle age43. These findings point to a fundamentally different pattern of work for younger cohorts of dentists than for older dentist cohorts. One factor that may influence work patterns is the increasing proportion of female dentists, who now comprise 36.5% of Australian dentists1. Female dentists tend to undertake more part-time work23, and have more career breaks, than male dentists44–46, which could have a substantial influence on total aggregate capacity to provide dental services. CONCLUSIONS The profile of services provided by dentists changed over the study period to include less emphasis on replacement of teeth and more on diagnosis, prevention, and retention of natural dentitions. Acknowledgements The Longitudinal Study of Dentists’ Practice Activity has been supported by the Australian Government Department of Health and Ageing, the National Health and Medical Research Council (NHMRC), and the Australian Institute of Health and Welfare (AIHW). This paper was written with support from a CRE (1031310) from the NHMRC. The contents are solely the responsibility of the administering institution and authors, and do not reflect the views of NHMRC. REFERENCES 1. Australian Institute of Health and Welfare. Dental Workforce 2012. National health workforce series No 7. Canberra, ACT: AIHW; 2012. p. 2014. 2. Mejia GC, Amarasena N, Ha DH et al. Child Dental Health Survey Australia 2007: 30-Year Trends in Child Oral Health. Canberra, ACT: AIHW; 2012. 3. Australian Bureau of Statistics. Dental Health (Persons Aged 15 Years or More) February – May 1979. Cat No. 4339.0. Canberra, ACT: ABS; 1979.
9. Brennan DS, Spencer AJ, Szuster FSP. Service provision trends between 1983–84 and 1993–94 in Australian private general practice. Aust Dent J 1998 43: 331–336. 10. Brennan DS, Spencer AJ. Service provision trends among Australian private general dental practitioners: 1983–84 to 1998–99. Int Dent J 2003 53: 449–452. 11. Brennan DS, Spencer AJ. Trends in service provision among Australian private general dental practitioners over a 20-year period. Int Dent J 2006 56: 215–223. 12. Elderton RJ, Eddie S. The changing pattern of treatment in the General Dental Service 1965–1981. Br Dent J 1983 55: 371–389, 421–423 13. Kleinman ER, Harper PR, Gallagher JE. Trends in NHS primary dental care for older people in England: implications for the future. Gerodontology 2009 26: 193–201. 14. Manski RJ, Moeller JF. Use of dental services: an analysis of visits, procedures and providers, 1996. J Am Dent Assoc 2002 133: 167–175. 15. Eklund SA, Pittman JL, Smith RC. Trends in dental care among insured Americans: 1980 to 1995. J Am Dent Assoc 1997 128: 171–178. 16. Eklund SA. Trends in dental treatment, 1992 to 2007. J Am Dent Assoc 2010 141: 391–399. 17. del Aquila MA, Anderson M, Porterfield D et al. Patterns of oral care in a Washington State dental service population. J Am Dent Assoc 2002 133: 343–351. 18. Barnard PD. Facts and Figures Australian Dentistry 1984–85. Sydney, NSW: Australian Dental Association; 1987. 19. Australian Institute of Health. Dental Workforce 1981. Health workforce information bulletin No 3 (Health workforce information series). Canberra, ACT: AGPS; 1988. 20. Australian Institute of Health and Welfare. Dental Practitioner Statistics, Australia, 1992. AIHW Dental Statistics and Research Series No. 6. Adelaide, SA: The University of Adelaide; 1994. 21. Szuster FSP, Spencer AJ. Dental Practitioner Statistics, Australia, 1994. AIHW Dental Statistics and Research Series No. 11. Adelaide, SA: The University of Adelaide; 1997. 22. Teusner DN, Spencer AJ. Dental Labour Force, Australia 2000. Canberra, ACT: Australian Institute of Health and Welfare; 2003. 23. Chrisopoulos S, Nguyen T. Trends in the Australian Dental Labour Force, 2000 to 2009: Dental Labour Force Collection, 2009. Canberra, ACT: AIHW; 2012. 24. Brennan DS, Spencer AJ, Szuster FSP. Dentist service rates and distribution of practice styles over time. Community Dent Oral Epidemiol 1996 24: 145–151. 25. Eklund SA. Changing treatment patterns. J Am Dent Assoc 1999 130: 1707–1712. 26. Murray JJ, Steele JG. 30 Years of preventive dentistry – and 30 years into the future. Dent Update 2003 30: 478–484, 486–487.
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37. Brennan DS, Spencer AJ, Slade GD. Service provision among adult public dental service patients: baseline data from the Commonwealth Dental Health Program. Aust N Z J Public Health 1997 21: 40–44. 38. Brennan DS, Ryan P, Spencer AJ et al. Dental service rates: age, period, and cohort effects. Community Dent Health 2000 17: 70–78. 39. Brennan DS, Luzzi L, Roberts-Thomson KF. Dental service patterns among private and public adult patients in Australia. BMC Health Serv Res 2008 8: 1. 40. Brennan DS, Spencer AJ. Practice activity trends among Australian private general dental practitioners: 1984–84 to 1998–99. Int Dent J 2002 52: 61–66.
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Correspondence to: David S. Brennan, Australian Research Centre for Population Oral Health, The University of Adelaide, Adelaide, SA 5005, Australia Email:
[email protected]
© 2014 FDI World Dental Federation
