National Study of Adult Oral Health 2017-18: Study design and methods.

The National Study of Adult Oral Health (NSAOH) is Australia's third national oral examination survey of a representative sample of Australian adults. The study was undertaken primarily to describe levels of oral health in the population and to describe trends since the first survey, conducted in 1987-88. The aim of the study was to complete 7,200 examinations, necessitating approximately 15,200 completed interviews. Survey participants were selected using a multi-stage probability sampling design that began with the sampling of postcodes within states/territories in Australia. Individuals within selected postcodes were then selected by the Australian Government Department of Human Services (DHS) from the Medicare database. Following an initial opt-out period, participants were given the option to either complete the questionnaire online or to complete the questionnaire via a computer-assisted telephone interview. Participants were asked a series of questions about their oral health and dental service use and those who reported having one or more of their own natural teeth were invited to undergo a standardised oral examination. Examinations were conducted by state/territory dental practitioners who underwent prior training and calibration in survey procedures by the Australian Research Centre for Population Oral Health (ARCPOH), The University of Adelaide.