Cross-sectional analysis of risk factors for subclinical periodontitis; active matrix metalloproteinase-8 as a potential indicator in initial periodontitis in adolescents

Background: The aim of this study was to investigate how different patient-related risk indicators might be associated with the odds of developing subclinical periodontitis in adolescents.

Methods: This cross-sectional study included 252 Finnish individuals aged 15 to 16 years, of whom 141 were boys and 111 girls. A specially trained dentist performed clinical examinations: measurements included periodontal indexes (bleeding on probing, visible plaque index, root calculus, and probing depth, smoking by pack-years, periodontal bacteria (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia, Prevotella nigrescens, and Treponema denticola) and the potential salivary periodontal biomarkers (active matrix metalloproteinase-8 [aMMP-8], polymorphonuclear leukocyte elastase [PMN elastase], and total protein, albumin, immunoglobulin A, immunoglobulin G, and immunoglobulin M). Results were analyzed by ordinal logistic regression, one-way analysis of variance, Fisher exact test, and Kruskal-Wallis H test.

Results: The main finding of this study was that subclinical periodontitis in adolescents was statistically significantly associated with elevated salivary aMMP-8 but not with PMN elastase. Also, adolescents with subclinical periodontitis had statistically significantly higher levels of bleeding on probing, root calculus, and dental plaque than adolescents without subclinical periodontitis.

Conclusions: We suggest that the main risk factor for subclinical periodontitis in adolescents is the partly calcified, dysbiotic bacterial biofilm, which interacts with the immune defenses of the host; this leads to gingival inflammation and eventually to deepening periodontal pockets. This proinflammatory subclinical periodontitis stage, which represents stage I periodontitis in the new classification, is reflected as elevated salivary aMMP-8 levels in oral fluids.