Patient views on dental amalgam. An exploratory questionnaire

An introductory letter and a precoded questionnaire was sent to a large sample of the Dutch population in order to study their views on dental amalgam. Another sample was approached by interviewers to study the effect of non-response and a third sample was asked to complete a 'neutral' questionnaire so as to preclude any influence caused by the phrasing of the introductory letter and the questionnaire. It was found that the non-response did affect the results, while the phrasing of the letter did not. Based upon the comparison of the samples and taking the non-response into account, it is concluded that probably 17% of the Dutch population regard amalgam to be potentially harmful. At least 4-5% worry about their health because of amalgam fillings and 2-3% attribute existing health problems to amalgam. However, none of the respondents of the 'neutral' sample spontaneously reports amalgam as a causative factor for illness. The health problems mentioned by the respondents are diverse. Headache is mentioned most often, followed by fatigue and a metal taste.