Every 10 years since 1968, a survey of the dental health of adults has been carried out. This survey provides information to underpin and help plan dental health care for the whole UK, although the 2009 survey did not include Scotland. The surveys help the NHS understand how the dental health of adults is changing.

People from all backgrounds take part in the survey, whether or not they go to the dentist, so we get an accurate picture of the dental health of adults in each country.

The survey was carried out by the Office for National Statistics (ONS) on behalf of NHS Digital, with funding provided by the Department of Health for England, Wales and Northern Ireland. ONS worked in collaboration with the NatCen Social Research (NatCen), Northern Ireland Statistics and Research Agency (NISRA), and a team of dental experts from the Universities of Birmingham, Cardiff, Newcastle, Dundee and University College London, and NHS dentists.

Addresses were chosen at random to make sure we get a truly representative picture of everyone living in each country. We interviewed adults from all backgrounds to get an accurate picture.

A letter was sent to the home of the respondent and an interviewer called to arrange an interview at a time that suited the respondent. Interviews were relaxed, no preparation was required and questions could be skipped.

Following the interview, there was the option of a short dental check-up by a dentist at the respondent's home. The dentist did not carry out any treatment and just looked at the teeth, with feedback about the check-up sent to the respondents. Respondents were encouraged to still go to see their own dentist as usual.

The survey and check-up covered:

• geographies
• sex
• age
• ethnic group
• household details
• general health and dental health
• experience of dental services and treatments
• dental examination results (tooth and gum condition)

The results from thousands of surveys are collected and used for research purposes only. Answers given are completely confidential and respondents can't be identified from the results we publish. Details are never passed to other organisations for commercial purposes.