Dental Calculus Composition. 1. Supragingival Calculus: Ash, Calcium, Phosphorus, Sodium, and Density

¹ Eastman Dental Dispensary, Rochester, New York

Individual samples of supragingival dental calculus from approximately 200 subjects exhibited a wide range in mineral content, as shown by the loss in weight on ashing at 900° C. (11-35 per cent) and density (1.3-1.9 dry weight). The calcium and phosphorus content of dry calculus ranged from 26 to 32 per cent and 14 to 17 per cent, respectively. The mean sodium content of the ash increased from 2 per cent in highly calcified to 4 per cent in less calcified pieces. The mean Ca:P ratio (wt.) in the ash was found to be 1.75 and in the calculus 1.803. Calculus from the buccal of the upper molars was found to contain more mineral than that from the lingual of the lower anterior teeth, except in very heavy calculus producers, where the calculus from both regions tended to be equally well calcified. The mineral content of calculus from the lingual of the lower anterior teeth did not appear to be dependent on the age of the subject or on the age of deposits a month or more old.