Association between salivary alkaline phosphatase levels and periodontal disease: a systematic review and meta-analysis

This updated meta-analysis evaluated salivary alkaline phosphatase (ALP) levels in individuals with gingivitis and periodontitis compared to periodontally healthy individuals. The review followed PRISMA guidelines and was registered in PROSPERO (CRD420251273461). Searches were conducted in PubMed, Scopus, ScienceDirect, Web of Science, EBSCO, and Google Scholar. Methodological quality was assessed using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Meta-analysis was performed using a random-effects model with Review Manager (RevMan) version 5.4.1 and STATA version 19. Twenty studies (n = 1459) were included; twelve were eligible for meta-analysis. No statistically significant differences emerged in salivary ALP levels between gingivitis and healthy controls (p = 0.15) or between those with gingivitis and periodontitis (p = 0.18). However, individuals with periodontitis had significantly higher salivary ALP levels compared to periodontally healthy individuals (MD = 44.62 [95% CI: 22.55 to 66.69]; p = 0.0010), with high heterogeneity (I2 = 100%). The included studies demonstrated variable methodological quality according to the JBI criteria, and the GRADE certainty was very low. Current data suggest an association between elevated salivary ALP levels and periodontitis, although methodological heterogeneity requires cautious interpretation and underscores the need for well-designed, standardized future research.