Variations in structure within the trabecular bone of the mandible.

A study of the intramandibular variations in bone mass, coarseness of the bone trabeculae and bone activity between incisor, premolar, and molar regions has been carried out, as well as estimation of possible differences in these variations between groups of mandibles with different dentition. The material consisted of 24 autopsy specimens of half mandibles from normal subjects. Microradiograms of ground sections from incisor, premolar, and molar regions were used. Quantitation of bone mass was done by an electronic point-counting system. The analysis indicates that (1) the variations in bone mass within same region are marked, (2) trabecular bone is denser and more delicately woven in the incisor region than in either premolar or molar regions, where mass of bone is the same, although there is probably more delicately woven trabecular bone in molar region, (3) bone activity lies on the same level all over in trabecular bone within the mandibular body and (4) the variations of these factors seem to be independent of state of dentition in the single mandible.