Methods: A total of 21 adults (12 men, 9 women, age range 32-75yr, mean age 48.3yr) participated and were classified into periodontitis-affected (P) and periodontitis-free (Po) groups based on the radiographic findings. Patients with ≥30 % marginal alveolar bone loss were selected to the P group (n=11) and subjects with no bone loss formed the Po group (n=10). At the time of plaque collection half of the periodontitis-affected subjects were fully treated while half were untreated. All available supragingival plaque was collected with Gracey curettes by gentle instrumentation. The calcium content of plaque (mg) was analyzed according to Pearce (1981) and the protein content (mg) using the method of Lowry et al. (1951). Comparisons were made between the P group and Po group, and between the treated and untreated P patients.
Results: The calcium content of plaque of the P group was significantly higher than that of the Po group, 0.116 (± 0.089) and 0.048 (± 0.045) Ca mg/mg protein, respectively (p<0.05, Student's t-test). There was no significant difference in the calcium content of plaque between treated and untreated P patients, 0.106 (± 0.077) and 0.124 (± 0.104) Ca mg/mg protein, respectively.
Conclusion: Irrespective of preceding periodontal treatment the calcium content of plaque seems to be significantly higher in subjects with periodontitis as compared to their periodontitis-free counterparts.