A questionnaire was sent to all persons 40 years of age (born in 1947) living in the county of Aust-Agder (n = 1547). The questionnaire included questions concerning dental office visiting habits, stability of relationship dentist-patient, and socio-economic status. 84% answered the questionnaire. Persons who answered that they did not have a recall agreement with any dentist were offered a free dental examination (324 of 1517). 83% had visited the dentist annually the last three years, thus considered to be stable patients. Regular patients were also very stable in relation to their dentist: 89% had visited same dentist for the last 5 years. Dental health data of persons without a recall agreement were examined clinically. Of 324 persons, 137 met for clinical examination. The data from these persons were classified according to socio-economic level and regularity of visiting habits. The DMFT number was almost independent of those variables. The DMFT-index's single components differed between the groups. The regular patients from higher socio-economic levels had more fillings. More missing teeth were found among irregular patients from lower socio-economic levels. This indicates that the latter group have chosen the least expensive alternative, i.e. extraction, when in need of acute treatment, and that they have a greater accumulated need of treatment. This tendency also applied to the need of periodontal therapy. More than 59% of persons with CPITN maximum score 3 or 4 belonged to irregular patients from lower socio-economic groups.