Due to recent increases in the number of cases of embedded mandibular third molars, the Department of Dental Radiology, Kyushu Dental College decided to investigate generational differences in their occurrence. For the purpose of investigation, 670 panoramic radiographs, obtained from two different generations (1970s and 1999s) of Kyushu Dental College students, wer used. There were significant statistical differences in the angle of eruption of the third molar between the 1970s and 1990s groups. The mandibular third molars in the 1990s group were growing at an abnormal angle (P < 0.05) and were closer to the mandibular canal (P < 0.05) than those in the 1970s group.