Muscle strength and mineral densities in the mandible.

Bone mineral density (BMD) in the femoral neck and lumbar spine was measured for 355 postmenopausal 48- to 56-year-old women and the BMD in five different regions in the mandible for 77. All 355 women were also classified according to the size of the masseter muscle. Both skeletal measures and the BMD of the buccal cortex distally from the foramen mentale were compared with the size of the masseter muscle. This study indicates that functional stress, caused by the masseter muscle, is involved in maintaining bone mineral density in edentulous regions of the mandible. Those individuals who are physically active or are bruxists may lose less mineral, after extractions of teeth, from those regions of the jaw bones where the muscles are attached.