Evaluation of salivary calprotectin as a marker for screening periodontitis using a latex agglutination turbidimetric immunoassay system: a cross-sectional study

BACKGROUND: Biomolecules in body fluids such as gingival crevicular fluid and saliva are used for the diagnosis of periodontitis. Saliva is easy to collect and salivary biomarkers are useful in screening periodontitis. The suitable salivary biomarkers and their measuring system are important for screening periodontitis in mass dental examination. Therefore, this study examined the potential of few salivary biomarkers for screening and diagnosis of periodontitis and aimed to evaluate more effective biomarkers and their measuring methods in dental examination. METHODS: Ninety-three individuals with and without periodontitis participated in this clinical examination and were classified into the non-periodontal diseases or stage I periodontitis (control, n = 26) and stage II-IV periodontitis groups (periodontitis, n = 67) after periodontal examinations. Unstimulated saliva samples were collected from participants. The levels of salivary biomarkers including calprotectin, hemoglobin (Hb), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), alanine aminotransferase and aspartate aminotransferase (AST) were automatically measured using the latex agglutination turbidimetric immunoassay (LATIA) and enzyme assay systems. Differences in clinical indicator and biomarker levels in the control and periodontitis groups and their correlations were statistically analyzed. A receiver operating characteristic (ROC) analysis of the ability of salivary biomarkers to predict periodontitis was also performed. RESULTS: Salivary calprotectin, Hb, LDH, ALP and AST levels were significantly higher in the periodontitis group than that in the control group. At the initial stage of periodontitis, a significant difference was only observed in calprotectin levels. Calprotectin and LDH levels strongly correlated with clinical indicators including probing pocket depth, clinical attachment level, bleeding on probing, gingival index and periodontal inflamed surface area with high correlation coefficient (calprotectin: 0.582-0.660, LDH: 0.534-0.614). Calprotectin showed a higher area under the ROC curve value (0.894), with 91% sensitivity and 73% specificity, than the other salivary biomarkers. CONCLUSIONS: Salivary calprotectin showed a high effectiveness for the diagnosis of periodontitis, and the measurement of salivary calprotectin using the LATIA system that is a high throughput method is suitable for population-based screening of periodontal diseases.