Methods: Eight subjects aged 35-44 years participated. All teeth of each subject were examined by a periodontist following CPI and LA criteria. Each participant received three examinations with 2-hour intervals in one day. The reproducibility was analyzed with kappa test. The effects of repeated probing on gingival bleeding, and pocket depths were analyzed with McNemar test.
Results: The site-specific CPI weighted kappa values were 0.57-0.60. The corresponding kappa values for LA were lower, 0.38-0.40, with wider 95% confidence intervals. Including or excluding the distal surfaces of third molars did not have significant change on kappa values of CPI and LA. However, reproducibility with CPI varies from tooth to tooth with the lowest kappa values at third molars. The weighted kappa values for CPI on sextant level were 0.43-1.00. Repeated probing had no significant effects on gingival bleeding and pocket depths.
Conclusion: The model of using three 2-hour interval examinations in one day could obtain good intra-examiner reproducibility for CPI and moderate for LA regardless site or sextant level. Regarding the variation of reproducibility from tooth to tooth, we recommend using site level as calibration before a periodontal survey is conducted.