Mechanical properties and density of bone in a case of severe endemic fluorosis.

Mechanical properties of 25 standardized specimens of compact bone from a 45-year-old man with extreme endemic fluorosis were compared with similar specimens of nonfluorotic bone. Data from dry and wet tested specimens were compared. Tensile strength, strain, energy absorbed to failure, and modulus of elasticity were reduced in fluorotic specimens while compressive strength, strain and energy were increased in both wet and dry specimens. Compressive properties exceeded tensile properties. Drying increased tensile and compressive strength and modulus but decreased tensile and compressive strength and energy absorbed. Dry specimens tended to follow Hooke's Law but wet specimens exhibited visco-elastic behavior. Wet fluorotic specimens had lower tensile properties but higher compressive properties and were more dense than fresh human compact bone.