Oral health equality during 30 years in Norway

Objectives: To study the relationship between income and edentulousness and having a functional dentition from 1975 to 2002, and to examine whether or not the findings can be characterized as a social gradient. Methods: Four datasets were collected by personal interviews and precoded questionnaires by Statistics Norway in 1975, 1985, 1995 and 2002. The datasets were representative of the non-institutionalized adult population in Norway. Each year, the sampled persons were distributed into five income quintiles. Four effects were examined of the relationship between income quintiles and edentulousness and functional dentition (1) the absolute equality effect, (2) the period effect, (3) the relative equality effect, and (4) the gradient effect. Results: The main finding is that in absolute terms oral health is more equally distributed in 2002 than in 1975, and the lowest income groups benefited the most in oral health. Among the elderly, however, having a functional dentition was less equally distributed in 2002. The relative differences increased for the oldest for each new birth cohort; thus, the chances of being edentulous was 7.5 times higher in the lowest income group versus the highest group in 2002, whereas the chances were only two times higher in 1972. Having lost all natural teeth was infrequent in 2002, and inequality wiped out in the population below >= 60 years. A small social gradient was still in 2002. Conclusions: The condition of edentulousness is a result of accumulated incidences of dental diseases and fragmented access to dental care. Economic barriers and unavailability of dental care postponed necessary restorative dental care and resulted in more drastic treatment solutions previously especially in the rural areas in Norway.