Comparison of trends in the prevalence of caries and restorations in young adult populations of several countries.

We compared DMFT (decayed, missing and filled teeth) values of young adult populations (about 18- to 21 yr old) obtained over two decades in five industrialized countries (Denmark, Finland, Israel, Japan, U.S.A.). Trends of the active disease factor (D) and treatment factor (F) within and between these countries during two decades were also compared. No uniform trend in caries prevalence data, based on total DMFT scores, was found. In some countries DMFT scores declined (Denmark, U.S.A.), in some they remained relatively static (Finland), and in some they increased during the last 20 yr (Israel, Japan). However, DMFT scores did not always correlate with untreated lesions, D, which decreased remarkably in Denmark and Finland and moderately in the U.S.A., remained stable in Japan, but increased in Israel. Similarly, treatment of caries, F, varied in different countries, increasing dramatically in Finland and Japan and moderately in Israel, remaining static in Denmark, and decreasing in the U.S.A. These trends appear to be influenced largely by the extent of caries-preventive measures (particularly fluorides) in the respective countries, and to a lesser degree by sugar utilization and the availability of dental personnel. This age population has not been studied in a comparative fashion previously. This study also emphasizes the importance of looking not only at DMFT scores but at the trends in meeting treatment needs, D vs F scores.