Bone mineral content of mandibles: Normal reference values—Rate of age-related bone loss

Summary

The purpose was to obtain the normal sex- and age-related reference values for the bone mineral content (BMC) in the bones of the mandible and the forearms, as estimated by dual-photon absorptiometry; to examine the effect of tooth loss on the mandibular BMC, i.e., BMC in the basal part of the mandible; and to analyze the rate of the sex- and age-related BMC loss in the mandible in normal old edentulous individuals ≥70 years of age and its relationship to the corresponding BMC loss in the forearm bones. The following groups were measured: young dentate adults (n=100; women (W): men (M)=1∶1), young, long-term edentulous W (n=15), and old edentulous individuals (n=24 W, 10 M). In the old group the BMC measurements were repeated after a 2- or 3-year period (n=18 W, 10 M). The analyses indicate that the mandibular BMC reference values differ by sex and age; but correction for the state of dentition seems of minimal benefit. The average BMC loss (%) in the bones of the mandible and the forearms seems to be higher in old W (1.5 and 1.4% per year) than in old M (0.9 and 0.7% per year), but of the same magnitude in each sex. The relationship between the BMC loss (%) in the two sites was significant (P<0.01) but rather weak. Thus, it seems important to follow the sex- and age-related BMC loss in the mandible separately.