[Statistical studies on numerical anomalies of teeth in children using orthopantomograms--congenital hypodontia]

Statistical studies on numerical anomalies of teeth using orthopanthomograms had been attempted. In this paper, congenital hypodontia had been researched using 4009 orthopanthomograms of pedodontic patients. The tested were following; Male: Age 2-5 1036, 6-11 905, 12-22 Total 1963 Female: Age 2-5 1032, 6-11 985, 12-29 Total 2046 respectively. Many interesting results have been acquired, i.e. A. Congenital Hypodontia of Deciduous Teeth total 62 cases (78 teeth) 1 tooth defect--46 cases 2 teeth defect--16 cases B. Congenital Hypodontia of Permanent Teeth total 314 cases (566 teeth) 1 tooth defect--150 cases 2 teeth defect--115 cases 3 teeth defect--23 cases 4 teeth defect--18 cases 5 teeth defect--6 cases 6 teeth defect--0 case 7 teeth defect--1 case 8 teeth defect--1 case C. Defect Position deciduous teeth i2--83.3% permanent teeth P2--42.4% I2--36.4% D. Rare cases Symmetric defect (upper and lower): 2 cases, bisymmetric defect (right and left): 93 cases, symmetric and bisymmetric defect: 7 cases, defect of deciduous teeth and the succeeding permanent teeth: 37 cases, or in other expression, 2 B 1 case, 5/5 1 case, B 2 B B 1 case, 2 2 17 cases, 2 2 4 cases, 1 1 1 case, 3 3 1 case, 5 5 1 case, 3 2 2 3 1 case, 5 2 2 5 1 case, 5 4 4 5 1 case, 7 2 2 7 1 case, 7 3 3 7 1 case, 7 5 5 7 1 case, 7 5 2/2 2/2 5 7 1 case, 5/5 5/5 7 cases and 2B 2B 1 case, 3C 3C 1 case, B2 B2 8 cases, C3 C3 2 cases, 2B 5 cases, 2B 1 case, B2 10 cases, A1 1 case, A1 1 case, B2 6 cases' E5 1 case... In addition, the data have no significant difference in right and left, male and female. And for many reasons, we criticize the established theory (?) that congenital hypodontia is a systemic degeneration in human evolution. So we propose a following, simple and not incompatible concept--eventually congenital hypodontia except hereditary cases appear in many chances when development of dental germs (I2, P2, M3) is later than the surroundings and the space for it is remarkably deficient.