Calprotectin levels in gingival crevicular fluid predict disease activity in patients treated for generalized aggressive periodontitis

Background and Objective: Clinical parameters such as probing depth and bleeding on probing are commonly used for monitoring after periodontal treatment. However, these parameters have poor prognostic utility. The biomarker calprotectin is used to monitor conditions such as inflammatory bowel disease because of its ability to predict disease activity. Levels of calprotectin in gingival crevicular fluid correlate with periodontal disease severity and treatment outcome. The validity of calprotectin as predictor for future periodontal disease activity has not yet been investigated. Material and Methods: Thirty-six subjects with generalized aggressive periodontitis were treated with scaling and root planing (SRP), and with adjunctive antimicrobial medications. Probing depth, clinical attachment level and bleeding on probing were assessed at baseline, and 3 and 6 mo after SRP. A gingival crevicular fluid sample was collected from the initially deepest site in each patient 3 mo after SRP and analysed for calprotectin levels. Activity was defined as a probing depth increase of > 0.5 mm between 3 and 6 mo at the sample site. The ability of individual parameters to predict activity was analysed by construction of receiver operating characteristic curves. Results: Nine active sites were identified. Clinical attachment level, probing depth, bleeding on probing and gingival crevicular fluid volume showed no predictive utility [area under the curve (AUC) < 0.6, p > 0.05]. However, calprotectin concentration (AUC = 0.793, p = 0.01) and the total amount/sample of calprotectin (AUC = 0.776, p = 0.02) significantly predicted activity. Patients with calprotectin levels above calculated cut-off values had significantly more active sites than patients with negative results. Conclusion: Calprotectin levels were predictors of disease activity at both site and subject levels. The calculated cut-off values provide a dichotomous basis for prospective evaluation of calprotectin as a diagnostic marker for monitoring periodontal treatment.