Yanagida I, Mori S
Osaka Daigaku Shigaku Zasshi. 1990 Dec;35(2):580-93.
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.
曾有人尝试利用口腔全景X线片对牙齿数量异常进行统计学研究。在本文中，利用4009例儿童牙科患者的口腔全景X线片对先天性缺牙进行了研究。测试对象如下：男性：年龄2至5岁1036例，6至11岁905例，12至22岁总计1963例；女性：年龄2至5岁1032例，6至11岁985例，12至29岁总计2046例。获得了许多有趣的结果，即：A.乳牙先天性缺牙总计62例（78颗牙），1颗牙缺失——46例，2颗牙缺失——16例；B.恒牙先天性缺牙总计314例（566颗牙），1颗牙缺失——150例，2颗牙缺失——115例，3颗牙缺失——23例，4颗牙缺失——18例，5颗牙缺失——6例，6颗牙缺失——0例，7颗牙缺失——1例，8颗牙缺失——1例；C.缺失位置，乳牙i2——83.3%，恒牙P2——42.4%，I2——36.4%；D.罕见情况，对称缺失（上下）：2例，双侧对称缺失（左右）：93例，对称和双侧对称缺失：7例，乳牙和后继恒牙缺失：37例，或以其他表述，2B1例，5/5 1例，B2BB1例，22 17例，22 4例，11 1例，33 1例，55 1例，3223 1例，5225 1例，5445 1例，7227 1例，7337 1例，7557 1例，752/2 2/2 5 7 1例，5/5 5/5 7例，2B 2B 1例，3C 3C 1例，B2 B2 8例，C3 C3 2例，2B 5例，2B 1例，B2 10例，A1 1例，A1 1例，B2 6例，E5 1例……此外，数据在左右、男女方面无显著差异。并且由于多种原因，我们对先天性缺牙是人类进化中的一种系统性退化这一既定理论（？）提出批评。因此我们提出如下一个简单且并非不相容的概念——最终，除遗传病例外，当牙胚（I2、P2、M3）的发育晚于周围组织且其空间明显不足时，先天性缺牙会在很多情况下出现。
