The relationship between gingival crevicular fluid cathepsin B activity and periodontal attachment loss in chronic periodontitis patients: a 2-year longitudinal study

This study aims to determine whether gingival crevicular fluid (GCF) cathepsin B levels, total activity (TA) and concentration (EC) predict progressive attachment loss (AL). Seventy-five previously untreated patients with moderate periodontitis were recruited. GCF was collected from 16 molar and premolar mesiobuccal sites and probing attachment level (PAL) and probing depth (PPD) were measured with an electronic probe. Gingival, gingival bleeding and plaque indices were then scored. Prior to baseline patients were given basic periodontal treatment after which the above procedures were repeated. Carefully localized radiographs were taken of the test teeth and repeated annually. Patients were seen 3-monthly for 2 yr and the procedures were repeated. One hundred and twenty-one AL sites, 90 rapid AL (RAL) and 31 gradual AL (GAL), in 49 patients were detected. Cathepsin B levels (TA & EC) at RAL sites were significantly higher (p<0.0001) than paired control sites at the attachment loss time (ALT) and prediction time (PT). Mean levels (TA & EC) over the study period at GAL sites were significantly higher (p<0.0001) than paired control sites. Using a critical value (CV) of 7.5 μU/30 s (TA) and 30 μU /μL (EC) showed a sensitivity of 100% and specificity of 99.83% (TA) and 100% and 99.75%(EC) at both ALT & PT. Mean cathepsin B levels (TA & EC) were significantly higher (p<0.0001) at RAL and GAL sites than nonattachment loss (NAL) sites in AL patients in intrapatient comparisons and mean patient levels were significantly higher (p<0.0001) in AL patients than NAL patients in interpatient comparisons. These results indicate that GCF cathepsin B may serve as a predictor of attachment loss.