Dental decay among Australian children

	

Summary
This report provides information on the dental decay experience of Australian children from the Child Dental Health Survey (CDHS) 2005. Data for this survey have been derived from routine examination data from a random sample of children enrolled in the School Dental Service (SDS). Decay experience is measured by the number of decayed, missing and filled teeth (dmft for deciduous teeth, DMFT for permanent teeth).
Main findings
Among Australian children aged 5–6 years:
•	nearly half (48.7%) had a history of dental decay in the deciduous teeth
•	the mean number of decayed, missing and filled deciduous teeth was 2.0
•	the mean number of decayed, missing and filled deciduous teeth of children from the lowest socioeconomic status areas was about 70% higher than for those from the highest socioeconomic status areas. This pattern was evident across all states and territories whose data were included in the analysis.
Among Australian children aged 12 years:
•	nearly half (45.1%) had a history of dental decay in the permanent teeth
•	the mean number of decayed, missing and filled permanent teeth was 1.1
•	the mean number of decayed, missing and filled permanent teeth of children from the lowest socioeconomic status areas was about 70% higher than for those from the highest socioeconomic status areas.

Contents
Summary
Main findings
Data collection methods and reporting
Dental decay in children aged 5–6 years
Prevalence
Severity
Untreated decay
Dental decay in children aged 12 years
Prevalence
Severity
Untreated decay
Abbreviations
References
Acknowledgments

Data collection methods and reporting
Data presented in this publication were sourced from the Child Dental Health Survey (CDHS) 2005, which monitors the dental health of children attending school dental services (SDS) operated by the health departments or authorities of Australian state and territory governments. 
Data for CDHS have been derived from routine examinations of a random sample of children enrolled in the SDS. Data were adjusted according to time since last dental examination so that children on longer recall intervals, who often have better oral health, were not under-represented in this analysis. State and territory estimates (ABS 2003) of the 2005–06 estimated resident population (ERP) within individual ages are used to provide numerators for weights that are divided by the age-specific number of cases in the samples from respective states and territories (see Ha et al. 2011 for a detailed description of data collection and analysis methods). The age groups of children aged 5–6 years and 12 years were chosen to present in this report, as these age groups have been widely used internationally for monitoring progress in child oral health (Federation Dentaire Internationale 1982).
Decay experience is expressed as the number of decayed, missing and filled teeth (dmft for the deciduous or baby teeth or DMFT for permanent or adult teeth). Three measures of decay experience are reported:
•	The prevalence of disease is measured by the proportion of children who have disease (dmft or DMFT more than 0). 
•	The severity of decay is measured by mean dmft and mean DMFT.
•	The need for dental treatment is measured by the proportion of children who have untreated decay (d or D more than 0).
Comparisons are made between boys and girls, across all available states and territories and across socioeconomic status groups. To help interpret results, 95% confidence intervals are reported for all results. 
New South Wales (NSW) and Victoria (Vic) have been excluded from this report, as data were not available. It is necessary to be cautious in drawing inferences among states and territories, as the differences may be the result of differences between states and territories in SDS coverage, level of enrolment, focus of services policy, or access to services in rural or remote areas.
Quartiles of the Socio-Economic Index for Areas (SEIFA) measure Index of Relative Socioeconomic Advantage/Disadvantage, developed by the Australian Bureau of Statistics (ABS 2006), are used to analyse differences in socioeconomic status (SES). A higher SEIFA index score indicated that an area has a relatively high proportion of people with high incomes or a skilled labour force, and is relatively advantaged. SEIFA scores were allocated to children according to the postcode of the location of the SDS clinic they attended.
In this report, the 25% of children attending clinics with the highest SEIFA index score is described as the ‘highest SES’. The 25% at the other end of the scale is described as the ‘lowest SES’ (see Ha et al. 2011 for a detailed description of data collection and analysis methods).
Dental decay in children aged 5–6 years
Dental decay (also called dental caries), both treated and untreated, in Australian children aged 5–6 years has declined significantly compared with the 1970s (Armfield 2008). In spite of this decline, this disease remains common in Australian children.
Prevalence
More than 20,000 children aged 5–6 years were included in this analysis. Nearly half (48.7%) of Australian children in that age group have had dental caries in their deciduous teeth (also called baby teeth). This figure varied across states and territories. It ranged from 41.7% in the Australian Capital Territory (ACT) and 41.8% in Western Australia (WA) to 57.3% in the Northern Territory (NT) (Figure 1).
Figure 1: Proportion of children aged 5–6 years with number of decayed, missing and filled deciduous teeth more than 0, by state and territory, 2005
Vertical bar chart showing, on the y-axis state/territory, and on the x-axis per cent.
Source: Child Dental Health Survey 2005
There was no difference in prevalence of decay between boys and girls. Children aged 5–6 years from the three lower SES areas had more dental decay than those from the highest SES areas (54.3% in the lowest SES and 39.3% in the highest SES) (Table 1). 
Table 1: Proportion of children aged 5–6 years with caries in deciduous teeth, 2005
Characteristic	Total number of children (unweighted number)	Percentage of children with dmft more than 0 (95% CI) (weighted number)	
Sex			
Boys	10,500	48.6 (47.8–49.5)	
Girls	10,173	48.7 (47.8–49.5)	
Socioeconomic status			
1 (lowest SES)	5,495	54.3 (53.1–55.6)	
2	4,847	51.1 (49.5–52.8)	
3	4,900	51.8 (50.8–52.8)	
4 (highest SES)	5,461	39.3 (38.2–40.4) 	
Note: Sex was not reported for all children
Source: Child Dental Health Survey 2005

Severity
In 2005, the mean number of decayed, missing and filled deciduous teeth among Australian children aged 5–6 years was 2.0.
Boys had a higher mean dmft than girls (2.3 compared with 1.8).
The mean dmft of children from the three lower SES areas were higher than for those from the highest SES area, with the biggest difference being between the lowest and the highest SES area. The mean dmft of children from the lowest SES areas was about 70% higher than for those from the highest SES areas (Figure 2). 
Means varied across states and territories, from a low of 1.5 in WA to 2.7 in the NT.
Figure 2: Mean number of decayed, missed and filled deciduous teeth (dmft) among children aged 5–6 years, by state and territory, sex, and socioeconomic status, 2005
Horizontal bar chart showing, on the y-axis, state/territory and socioeconomic status, and on the x-axis dmft.
Source: Child Dental Health Survey 2005
The gradient in worsening oral health with decreasing advantage was consistent across the states and territories. Decay experience of children from the lowest SES areas was between 22% (WA) and 139% (NT) higher than for children from the highest SES areas (Figure 3). 
Figure 3: Mean number of decayed, missing and filled deciduous teeth (dmft) among 
children aged 5–6 years, by socioeconomic status and state and territory, 2005
Vertical bar chart showing, for socioeconomic status, on the y-axis dmft and on the x-axis state/territory.
Source: Child Dental Health Survey 2005

Untreated decay
The presence of untreated decay can be used as an indicator of a need for dental treatment. More than 40% of Australian children aged 5–6 years had untreated decay (Table 2). The proportion of children with untreated decay varied among states and territories from 29.3% in the ACT to 49.7% in the NT. Consistent with previous results, children aged 5–6 years from the three lower SES areas had more untreated decay than children from the highest SES areas.
Table 2: Prevalence of untreated decay in deciduous teeth of children aged 5–6 years, 
by state and territory, sex, and socioeconomic status, 2005
Characteristic	Total number of children (unweighted number)	Total number of children 
(weighted number)	Percentage of children with untreated decay (95% CI)
(weighted number)	
State/territory				
Qld	1,332	16,360	44.5 (43.7–45.3)	
WA	2,993	4,930	34.3 (32.9–35.6)	
SA	13,427	3,052	35.9 (34.2–37.6)	
Tas	160	966	44.4 (41.3–47.5)	
ACT	1,747	756	29.3 (26.0–32.5)	
NT	1,044	618	49.7 (45.7–53.6)	
Sex				
Boys	10,500	13,040	42.4 (41.6–43.3)	
Girls	10,173	13,632	40.2 (39.4–41.1)	
Socioeconomic status				
1 (lowest SES)	5,495	6,227	47.9 (46.6–49.1)	
2	4,847	3,529	44.4 (42.7–46.0)	
3	4,900	9,181	45.9 (44.9–46.9)	
4 (highest SES)	5,461	7,745	29.2 (28.2–30.2)	
Australia	20,703	26,683	41.3 (40.7–41.9)	
Note: Sex was not reported for all children
Source: Child Dental Health Survey 2005

Dental decay in children aged 12 years
There has been a considerable decline in caries experience since the 1970s, with the mean number of decayed, missing and filled permanent teeth (DMFT) of Australian children aged 12 years decreasing from 4.8 in 1977 to 1.1 in 2005. However, dental decay remains a common disease among Australian children.
Prevalence
Nearly 9,000 children aged 12 years were included in this analysis. Across Australia, 45.1% of children aged 12 years had decay in their permanent teeth. Tasmania (Tas) had the highest proportion of children aged 12 years with a history of decay (53.4%), while WA had the lowest proportion (39.6%) (Figure 4). 
Figure 4: Proportion of children aged 12 years with DMFT more than 0, by state and territory, 2005
Vertical bar chart showing, on the y-axis state/territory, and on the x-axis per cent.
Source: Child Dental Health Survey 2005
The prevalence of decay in children aged 12 years was somewhat higher in girls than in boys (46.5% compared with 43.8%). Children from the lowest SES areas had more decay than those from the highest SES areas (53.1% compared with 37.1%, respectively) (Table 3).
Table 3: Proportion of children aged 12 years with DMFT more than 0, by sex and socioeconomic status, 2005
Characteristic	Total number of children (unweighted data)	Percentage of children with DMFT more than 0 (95% CI)
(weighted data)	
Sex			
Boys	4,503	43.8 (42.6–45.0)	
Girls	4,338	46.5 (45.2–47.7)	
Socioeconomic status			
1 (lowest SES)	2,422	53.1 (51.1–55.2)	
2	2,105	41.6 (39.4–43.9)	
3	2,076	47.5 (46.1–48.9)	
4 (highest SES)	2,242	37.1 (35.4–38.9)	
Note: Sex was not stated for all children
Source: Child Dental Health Survey 2005

Severity
In 2005, the mean number of decayed, missing and filled permanent teeth (DMFT) among Australian children aged 12 years was 1.1.
WA had the lowest mean DMFT score (0.9) while the NT, Tas and Queensland (Qld) had the highest mean DMFT scores (1.2 for each state/territory) (Figure 5).
Figure 5: Mean number of decayed, missing and filled permanent teeth (DMFT) among children aged 12 years, by state and territory, sex, and socioeconomic status, 2005
Horizontal bar chart showing, on the y-axis state/territory and socioeconomic status, and on the x-axis DMFT.
Source: Child Dental Health Survey 2005
Figure 6 shows the differences in DMFT score among socioeconomic groups within states and territories. There was a consistent pattern showing children from the lowest SES areas had more caries than those from the highest SES areas across most states and territories. However, the relationship between the DMFT score and socioeconomic status was less consistent than that seen in the deciduous teeth.
Figure 6: Mean number of decayed, missing and filled permanent teeth (DMFT) among children aged 12 years, by socioeconomic status and state and territory, 2005
Vertical bar chart showing, for socioeconomic status, on the y-axis DMFT, and on the x-axis state/territory.
Source: Child Dental Health Survey 2005

Untreated decay
The presence of untreated decay can be used as an indicator of a need for dental treatment. Nearly one-quarter (24.8%) of Australian children aged 12 years had untreated decay (Table 4). The proportion of children with untreated decay in their permanent teeth ranged from 19.1% in the ACT and 19.7% in WA to 30.7% in the NT. Among children aged 12 years, those from the lowest SES areas had more untreated decay than those from the highest SES areas (30.8% compared with 17.9%).
Table 4: Prevalence of untreated decay in permanent teeth of 12 year old children, by state 
and territory, sex and socioeconomic status, 2005
Characteristic	Total number of children (unweighted number)	Total number of children (weighted number)	Percentage of children with untreated decay (95% CI)	
States and territories				
Qld	668	7,430	26.7 (25.7–27.7)	
WA	1,322	2,368	19.7 (18.8–21.3)	
SA	5,792	1,456	22.3 (20.1–24.4)	
Tas	69	444	29.5 (25.3–33.6)	
ACT	670	291	19.1 (14.5–23.6)	
NT	324	271	30.7 (25.2–36.2)	
Sex				
Boys	4,503	6,369	24.8 (23.7–25.8)	
Girls	4,338	5,890	24.9 (23.8–26.0)	
Socioeconomic status				
1 (lowest SES)	2,422	2,270	30.8 (28.9–32.7)	
2	2,105	1,855	23.7 (21.8–25.6)	
3	2,076	5,085	26.7 (25.5–28.0)	
4 (highest SES)	2,242	3,050	17.9 (16.5–19.3)	
Australia	8,845	12,260	24.8 (24.0–25.6)	
Note: Sex was not stated for all children
Source: Child Dental Health Survey 2005

Abbreviations
CI		confidence interval
CDHS		Child Dental Health Survey
d		decay in deciduous (or baby) teeth
D		decay in permanent (or adult) teeth
dmft 		decayed, missing and filled deciduous (or baby) teeth  
DMFT 		decayed, missing and filled permanent (or adult) teeth 
SDS		school dental service
SEIFA		Socio-Economic Index for Areas
SES		socioeconomic status
NSW		New South Wales
Vic		Victoria
Qld		Queensland
WA		Western Australia
SA		South Australia
Tas		Tasmania
ACT		Australian Capital Territory
NT		Northern Territory
References
ABS (Australian Bureau of Statistics) 2003. Population by age and sex: Australian States and Territories, June 2003–04. Cat. no. 3201.0. Canberra: ABS.
Armfield JM & Spencer AJ 2008. Quarter of a century of change: caries experience in Australian children 1977–2002. Australian Dental Journal 53(2):151–9.
ABS (Australian Bureau of Statistics) 2006. Statistical geography: volume 1 Australian Standard Geographical Classification (ASGC) 2006. ABS cat. no. 1216.0. Canberra: ABS.
Federation Dentaire Internationale 1982. Global goals for oral health for the year 2000. Journal of Dental Research 31(1):74–7.
Ha DH, Roberts-Thomson KF & Armfield JM 2011. The Child Dental Health Survey 
2005–2006. Dental statistics and research series no. 59. Cat. no. DEN <>. Canberra: AIHW.

Acknowledgments
The author of this report was Diep Ha of the Dental Statistics and Research Unit at the Australian Institute of Health and Welfare (AIHW).
This research is supported by the AIHW.
We wish to acknowledge the extensive time and effort contributed by the state and territory health authorities in collecting and providing the data used in this publication, along with the continued cooperation of individual dentists and dental therapists.

The Dental Statistics and Research Unit (DSRU) is a collaborating unit of the AIHW established in 1988 at The University of Adelaide, located in the Australian Research Centre for Population Oral Health (ARCPOH), School of Dentistry, The University of Adelaide. The research unit aims to improve the oral health of Australians through the collection, analysis and reporting of information on oral health and access to dental care, the practice of dentistry and the dental labour force in Australia. 
© Australian Institute of Health and Welfare 2011 
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This publication is part of the Australian Institute of Health and Welfare’s Dental Statistics and Research Unit research report series. A complete list of the Institute’s publications is available from the Institute’s website <www.aihw.gov.au>. 
ISSN 1445-775X 
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Suggested citation 
Australian Institute of Health and Welfare 2011. Dental decay among Australian children. Research report series no. 53. Cat. no. DEN 210. Canberra: AIHW. 
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