Salivary MMP-8 Flagged Periodontitis Where Smoking Suppressed Bleeding Signs

Edited by Hygienetown staff

Salivary matrix metalloproteinase-8 kept its diagnostic accuracy in heavy smokers whose gingival bleeding was suppressed by tobacco, holding an area under the curve of 0.831 in that subgroup, according to a cross-sectional study published Aug. 15 in Clinical Oral Investigations.

Bleeding on probing ran higher in nonsmokers with Stage III Grade B periodontitis, at 44.6%, than in heavy smokers with Stage III Grade C disease, at 30.9% — the more severe grade showing the lesser bleeding. That difference did not reach statistical significance after Bonferroni correction, at P = .593, but the direction is consistent with tobacco-induced vasoconstriction dampening the bleeding response.

Across the full sample, MMP-8 reached an area under the curve of 0.855, with sensitivity of 82.5% and specificity of 85.0%. Within the smoker subgroup, specificity rose to 90.0% while sensitivity fell to 75.0%. MMP-8 significantly outperformed MMP-9, which reached 0.702, at P = .005.

Researchers enrolled 80 systemically healthy adults across four groups of 20: periodontally healthy nonsmokers, nonsmokers with Grade B disease, periodontally healthy heavy smokers, and heavy smokers with Grade C disease. Each underwent full-mouth examination covering probing depth, bleeding on probing, clinical attachment level, plaque index, and radiographic bone loss, with unstimulated whole saliva analyzed by ELISA.

Hypoxia-inducible factor 1-alpha showed no diagnostic value at all, at 0.453, though smoking independently suppressed it, at P = .007. The authors position it as a marker of tobacco-driven hypoxia adaptation rather than of periodontal disease.

The authors concluded that salivary MMP-8 offers adjunctive diagnostic value unaffected by the masking of gingival bleeding, supporting its use as a point-of-care adjunct where bleeding-based indices may understate inflammatory burden.

M. F. Bozaba, C. Atalay, Gokhan Kasnak, H. Toygar, and N. Balci conducted the study at institutions in Istanbul.

The design was cross-sectional with 20 patients per group, so it establishes discrimination between defined groups rather than performance in an unselected clinical population, and cannot show whether MMP-8 tracks disease activity over time.

Sources:
Clinical Oral Investigations, “Diagnostic accuracy and smoking-driven modulation of salivary MMP-8, MMP-9, and HIF-1a in stage III grade B/C periodontitis: a cross-sectional study,” published online Aug. 15, 2026: link.springer.com/10.1007/s00784-026-07056-7
PubMed, PMID 42603195: pubmed.ncbi.nlm.nih.gov/42603195