The aims of the present study were to evaluate the prevalence and severity of oral health impacts among adults and to analyse the effects of age, gender, level of education, number of teeth, and removable denture wearing on these impacts. Nationally representative data (n = 5,987) on Finnish adults aged 30+ yr were gathered in an interview, in a clinical examination, and by a questionnaire including the 14-item Oral Health Impact Profile. Subject age and the number of teeth were significantly associated with oral impacts (occurring fairly or very often) when the effects of gender, educational level, and removable dentures were considered. When subjects ≥ 75 yr of age were used as the reference group, the odds ratios (95% confidence interval) were 0.5 (0.3–0.8) and 0.7 (0.5–0.9) for 30–34-yr-old and 34–74-yr-old subjects, respectively. The odds ratios for those with 1–9 teeth and for those who were edentate were 3.4 (2.4–4.9) and 4.0 (2.6–6.3), respectively (20+ teeth as reference). Number of teeth modified the effect of denture wearing, and age modified the effect of educational level on oral impacts. Impaired subjective oral health related to many missing teeth might be improved by wearing removable dentures. Population groups needing special attention are young people with low education and those for whom only a few missing teeth are replaced with removable dentures.