Relationship between total and ionized calcium concentrations in human whole saliva and dental plaque fluid

Ionized and total calcium were determined with an ion-selective electrode in unstimulated whole saliva and in simultaneously collected plaque fluid. The mean ionic and total concentrations in saliva from 20 subjects were 0.53 and 1.03 mmol/l respectively, and in plaque fluid 0.64 and 1.20 mmol/l. The total calcium concentration in saliva was closely related to the total calcium concentration in plaque fluid (r = 0.95, p less than 0.001) as was the ionized calcium concentration in saliva to that of plaque fluid (r = 0.84, p less than 0.001).