Comparison of the clinical status of third molars in young men in 1949 and in 1990.

We investigated the clinical status of third molars in 876 Finnish conscripts aged 19.9 years (SD, 1.1 years) and compared the findings with data on male students of the same age from 40 years before. Significantly more partially erupted and fewer totally erupted lower third molars were found in the present study than 40 years earlier: 29% (95% confidence interval +/- 3%) versus 19% were partially erupted (p > 0.001), and 13% (confidence interval +/- 3%) versus 23% were totally erupted (p < 0.001). Fifty-eight percent of the lower third molars in the present study were clinically missing, whereas 13% (confidence interval +/- 2%) were totally erupted. The respective percentages in the upper jaw were 56% (confidence interval +/- 3%) versus 38% (confidence interval +/- 3%). Thirty-eight percent (confidence interval +/- 3%) of our subjects had one or two partially erupted third molars in the mandible and 10% (confidence interval +/- 2%) in the maxilla.