A Study of the Ontogenetic Origin of Human Permanent Tooth Germs.

Many authors such as Morgenstern, ROse, Ahrens and N or b e r g have reported about the origin of the permanent tooth germs but the later development of this dentition has not been well illustrated. And there are few, if any, detailed studies concerning the position changes during development of permanent tooth germs. The present author previously (1957) postulated that deciduous tooth germs originate from oral epithelium, with the so-called dental lamina being formed through mesio-distal connection of the dental anlages. Furthermore the free margin of the dental lamina has a wavy contour from the very beginning of development. The author also reported in 1956, -59 and -62 position changes during development of the deciduous tooth germs. He observed the deciduous tooth germs pass through a physiologic crowded condition of the dental arch. More recently, the author has studied the origin and position changes during development of permanent tooth germs of the fetus. The present paper will describe some new findings only on the origin. Materials and method are the same as described in previous studies. Refer to the materials listed in the papers written in 1956 and 1962.