TOOTH ERUPTION: AXIAL MOVEMENT OF TEETH WITH LIMITED GROWTH

¹ Foundation for Dental Research of the Chicago College of Dental Surgery, Chicago, Ill.

It could be shown that root growth and bone growth are the 2 factors responsible for the axial movement of erupting human teeth. More specifically, it is the growth of the pulp in a restricted proliferation zone at the apical end of the tooth above the inflected epithelial sheath, and the proliferation of the osteogenic tissue preceding bone apposition which combine to supply the "force" of eruption.

The root ends of single-rooted teeth rest upon cushioned hammock ligaments anchored in bone and periodontal membrane. This ligament consists of a network of strong fibers and large amounts of fluid contained in round spaces between the fibers. It supports the growing root end and directs its growth which becomes the one component of axial movement. It acts at the same time as an equalizer for the "pressure" exerted by the growing bone at the alveolar fundus. The bone grows by the formation of concentric bone trabeculae; the formation of a new trabecula is initiated by irregular proliferation of short bony sprouts from the surface of the old bone trabecula. The cushioned hammock ligament correlates root (pulpal) growth and bone (osteogenic tissue) growth to one coordinated "force" of eruption.

The amount of bone formed behind the moving tooth is different in different teeth and is proportional to the distance a tooth travels during Weinmann's second phase of eruption.

After establishment of the bifurcation and during the later development of the roots, in multirooted teeth, bone grows only at the crest of the interradicular septum. Thus, the tooth is lifted upward in its alveolus, and the root grows simultaneously into the periapical area. In such teeth not one of the complicated structures which correlate bone and root growth in single-rooted teeth can be seen.

After the root is fully developed, bone apposition at the alveolar fundus is the "force" of eruption.

This article has been cited by other articles:

				G.E. Wise and G.J. King Mechanisms of Tooth Eruption and Orthodontic Tooth Movement J. Dent. Res., May 1, 2008; 87(5): 414 - 434. [Abstract] [Full Text] [PDF]