It is virtually impossible to compare the results of the many studies of traumatic dental injuries, primarily because information is lacking or inaccurate. Another reason, however, is that the basic materials differ substantially. Most studies are based on special groups comprising trauma patients exclusively, and furthermore these are often selected patients, although this fact is not always made clear. In recent years a number of Danish studies have attempted to examine the trauma problem on a population basis. The results of these studies are discussed, a few new results are added and attention is pointed out to problems needing further investigation.