Caries affecting bone is a chronic inflammation, with rarefaction or absorption of bone-tissue attended by suppuration; it is molecular death of bone, being a disintegration of the tissue. Both necrosis and caries of bone bear the same relation to the osseous tissue, that gangrene and ulceration do to the soft tissues. When percussion is made a different sound is distinguished between necrosis and caries of bone, owing to the difference in the degree of density. The probe reveals a sharp sound in the case of necrosed bone, owing to its hardness, while the use of this instrument reveals a dull sound in the case of caries of bone, and the probe also penetrates the diseased structure.

The causes of caries of bone depend upon a chronic inflamma-tory condition generally due to tubercular or syphilitic infection. Among the bones most frequently attacked are the bones of the face, and the lower jaw, especially the latter. The syphilitic form most commonly affects the bones of the nose and palate. When carious bone is exposed, it is found to be softened and disintegrated, and portions have been removed by liquefaction or absorption, leaving a greater or less cavity, the surface of which is covered with granulations and pus. Among the granulations may be found small spiculae of dead bone, surrounded by pus. In caries of bone resulting from syphilis, ulceration destroys the external surface of the bone, leaving a granulating surface, discharging the gummy pus. 10

Treatment

The treatment of caries of bone consists in removing the carious portion with the bone-chisel and sharp spoon and disinfecting the entire tract with hydrogen peroxide or caustic pyrozone, then packing the wound with iodoform gauze, soaked in a mixture of balsam of Peru containing ten per cent. of guiacol. The constitutional treatment consists in the giving of tonics, such as iron, quinine, cod-liver oil, and malt extracts, and nourishing food.