The author has observed 64 films from M. P. D. syndrome cases taken in Dept. of Radiology, the Infirmary of Dental College, Seoul National University in 1974, and obtained the following results: 1. In M. P. D. syndrome, the ratio between the female and the male were 2:l. 2. The prevalenting age were aged 20, 30, 10, and 40 in decreasing order. 3. The incidence was 21.8% in the left side, 29% in the right, and 21% was bilaterally, which show the right most frequent. 4. The roentgenograms revealed variable findings in each case, but there were not recognized any significant differences.