Reliability of Gingival Bleeding on Probing and Periodontal Probing Depth

Objectives: To assess the reliability of bleeding on probing (BOP) and periodontal probing depth (PD) after repeated probing at a time interval of four hours between re-examination procedures in patients with plaque induced gingivitis. Materials and methods: Fifteen non-smoking adult volunteers, 18-25 years of age, with plaque induced gingivitis participated. Full mouth examination was performed twice for the same subjects. Periodontal probing depth (PD1/mm and PD2/mm), bleeding on probing (BOP1 and BOP2), and bleeding index (BI1 and BI2) were assessed at six sites of each tooth present. Probing was repeated 4 hours (T2) after the first probing (T1). Intra- and Inter-examiner patterns of re-examination were considered. Results: When ignoring the re-examination pattern, subject-specific analysis revealed mean differences of 0.061, - 0.005, and - 0.003 for PD, BI, and BOP respectively. In addition, kappa statistics were employed for site-specific analysis, in which the highest kappa value of 0.481 was found when assessing PD. Thorough subject-specific analysis of intra-examiner agreement for both examiners showed mean differences close to zero for all three variables. Fair kappa values of 0.544 and 0.465 were obtained from site-specific analysis of PD for E1 and E2, respectively, while poor values were resulted for both BI and BOP. When inter-examiner pattern of re-examination was considered, analysis of agreement revealed mean differences close to zero for all variables. Kappa values were found to be fair for PD, but poor for both BI and BOP. It is concluded that no significant difference between inter- and intra-examiner reliability in the assessment of PD, BI, and BOP was found. In conclusion: the assessment of PD showed to have fair agreement, while that of BI and BOP was poor