RADIOGRAPHIC MEASUREMENT OF ALVEOLAR BONE LOSS IN THE LIVING RAT

WE DESCRIBE A METHOD WHICH allows longitudinal measurements of alveola r bone loss in the living rat. The anesthetized animal is kept in a fi xed and reproducible position and radiographs of an upper molar arch a re taken with a mammograph. In a preliminary study, 4 rats were repeat edly radiographed. In the main study, 10 rats were radiographed at day 0 and after 63 days of diet known to cause periodontitis. The radiogr aphs were enlarged and the amount of bone lost calculated by comparing the weights of the interdental areas reproduced on standard paper. In the preliminary study, the coefficient of variation (C.V.) of the ave rage weights of paper were fairly low (4 to 9%) in the first 3 rats, a nd amounted to 17% in the fourth. A statistically significant average loss of bone (16%) was found in the 10 rats in the main study when com paring the weights of papers at days 0 and 63.