Assessing time trend in health and health-related factors is important in monitoring population health and its determinants. The social and economic changes have been at a fast pace in recent times. However, the rate of change is not similar for every population subgroup. There were also different changes in policies and practices related to dental service delivery for children between states and territories. All these differences can have an effect on child oral health.

This chapter presents an analysis of trends between the current Survey and several existing surveys of child oral health in Australia. Australia's previous national survey among children, the National Oral Health Survey of Australia (NOHSA) was conducted in 1987–88. Dental caries experience was collected for samples of children across Australia. The National Survey of Adult Oral Health (NSAOH) 2004-06 collected dental fluorosis experience that allows for analysing time trend of fluorosis by year of birth (Slade et al. 2007).

The other available surveys are a series of the National Dental Telephone Interview Surveys (NDTIS) 1994–2013 and the Child Dental Health Surveys (CDHS) series. Dental service use by Australian children has been routinely collected in the NDTIS. The CDHS series collects administrative data on the oral health status of children attending school dental services in Australian states and territories. Therefore, those surveys covered just a proportion of the child population within each state/territory. This difference should be taken into account in interpreting results of this analysis. The CDHS data have been presented for age groups 6 years and 12 years. The presented data had been collected in Australia for the CDHS series from 1989 to 2010.

Two other oral epidemiological studies conducted among children attending school dental services were the Child Fluoride Study (CFS) Mark I 1992–93 and the Child Fluoride Study Mark II 2002–03. The CFS Mark I was conducted in Queensland and South Australia while the CFS Mark II was conducted in four states: Queensland, South Australia, Victoria and Tasmania. Information on child oral health behaviours was collected.

Trends in oral health status

Trend in dental caries experience

Time trend in dental caries experience was assessed using the NOHSA 1987–88, the CDHS series and the NCOHS 2012–14.