Relationship between bone-type alkaline phosphatase levels in gingival crevicular fluid and clinical parameters during supportive periodontal therapy

Periodontal tissues such as periodontal ligaments are known to have high alkaline phosphatase (ALP) activity, and the genotype of ALP in periodontal ligament is reported to the bone-type. Therefore, if periodontal tissues are damaged by periodontitis, bone-type ALP (BAP) may be released in gingival crevicular fluid (GCF). The aim of this study was to compare the values of BAP in the GCF in patients during supportive periodontal therapy (SPT) with clinical parameters, as a contribution to knowledge regarding early clinical diagnosis of the disease. Thus, we sampled GCF from healthy sites (probing depth (PD) ≤4 mm and bleeding on probing (BOP) (-) ) and diseased sites (PD ≥4 mm and BOP (+) ) from 76 patients receiving SPT. We then measured clinical parameters; plaque index (PI), amount of GCF, gingival index (GI), PD, clinical attachment level (CAL), BOP and alveolar bone resorption. Biochemical parameters included the amount of BAP, aspartate aminotransferase (AST) activity and amount of protein. In addition, we defined a cut-off value for the amount of BAP for analysis.