DIAGNOSTIC ACCURACY OF SALIVARY MICROBIOLOGICAL TESTS FOR PERIODONTITIS AND CARIES: A SYSTEMATIC REVIEW

Abstract Saliva is an attractive diagnostic medium for oral diseases because it is non-invasive, inexpensive, and easy to collect at scale. This systematic review evaluated the diagnostic accuracy of salivary microbiological tests for periodontitis and dental caries. We searched MEDLINE (PubMed), Scopus, and Web of Science from inception to 26 October 2025 for original studies that measured salivary microorganisms against accepted clinical reference standards for periodontitis or caries. Twelve original studies met inclusion criteria (periodontitis, n=6, caries, n=6). For periodontitis, multiplex qPCR panels and 16S-based models showed good to excellent discrimination: area under the receiver operating characteristic curve (AUC) commonly ≥0.90 for multifeature indices, with sensitivity,specificity typically >80% in internal validation. Single-species cut-offs performed inconsistently. For caries, very high salivary Streptococcus mutans by culture predicted longitudinal caries progression in preschoolers, and several 16S, qPCR models discriminated severe early childhood caries with moderate-to-good accuracy. Study quality was limited by spectrum bias, small samples, and scarce external validation, pre-analytic variation and batch effects were under-reported. Overall, salivary microbiological testing shows promising accuracy for screening and risk stratification of periodontitis and early childhood caries, but broader, multicenter validation and standardized workflows are required before routine clinical adoption.