Missing teeth and lost teeth of adults aged 30 years and over in south-western Finland.

The majority of Finnish adults have lost one, some or all of their teeth. The prosthetic replacement of missing teeth has thus been an important element of adult dental care. However, there have been no longitudinal studies focusing on the development of oral health among the Finnish adult population in terms of further tooth loss. A baseline sample from 1977-78 was selected from the city of Turku to represent the adult population aged 30 years and over. Ten years later, a follow-up examination was carried out on this baseline study group. A new sample of persons aged 30-39 years was also obtained to provide cross-sectional information, allowing comparisons between this study group and the youngest age-group of the 1977-78 study. In 1977-78, 52 per cent of all subjects had 20 or more remaining teeth. The mean number of missing teeth was 15.8 (SD 11.05) and the corresponding median 12 teeth. The number of missing teeth was on average higher in the older age-groups (P < 0.001). Women had more missing teeth than men (P < 0.01). In the ten-year follow-up study, the mean number of lost teeth was 1.5 (SD 2.32) and the median one tooth. The average number of lost teeth increased with age (P < 0.01). The rate of tooth loss was highest for those with 10 to 19 teeth at baseline, second highest for those with one to nine teeth and lowest for those with 20 to 32 teeth (P < 0.001). The reasons most often reported for tooth extraction were tooth mobility, pain and prosthetic treatment. In the cross-sectional study groups of persons aged 30-39 years, the proportion of subjects with a complete natural dentition of 28 to 32 teeth was 63.4 per cent in 1989, compared with 40.0 per cent ten years earlier. The average number of missing teeth was lower in 1989 than in 1977-78 (mean 4.7, SD 3.81 vs. mean 7.8, SD 6.92; P < 0.001). In both cross-sectional examinations women had a higher mean number of missing teeth than men. However, the difference between the genders was statistically significant only in 1977-78 (P < 0.01). Among the age-group of 30-39 years, there has been a considerable improvement in retention of natural teeth during the ten-year interval. However, among the middle-aged and elderly population reduced dentition was common; in addition, extraction was still used as a dental treatment especially among persons with reduced dentition. This suggests that the need for prosthetic replacement of lost teeth will continue to play a role in adult dental care in Finland for some decades to come.