Salivary MMP-8 Held Diagnostic Accuracy for Periodontitis in Heavy Smokers

Edited by Dentaltown staff

Salivary matrix metalloproteinase-8 distinguished periodontitis from periodontal health with an area under the curve of 0.855 and kept comparable accuracy in heavy smokers, according to a cross-sectional study published Aug. 15 in Clinical Oral Investigations.

Researchers enrolled 80 systemically healthy adults across four groups of 20: periodontally healthy nonsmokers, nonsmokers with Stage III Grade B periodontitis, periodontally healthy heavy smokers, and heavy smokers with Stage III Grade C periodontitis. Each underwent full-mouth periodontal examination covering probing depth, bleeding on probing, clinical attachment level, plaque index, and radiographic bone loss.

Unstimulated whole saliva was analyzed by ELISA for MMP-8, MMP-9, and hypoxia-inducible factor 1-alpha. Analyses included Kruskal-Wallis testing with Dunn-Bonferroni post hoc comparisons, log-transformed general linear models adjusted for age, sex, and body mass index, and receiver operating characteristic analysis with bootstrapped confidence intervals.

MMP-8 reached an area under the curve of 0.855, with sensitivity of 82.5% and specificity of 85.0%. In the smoker subgroup, it held at 0.831, with sensitivity of 75.0% and specificity of 90.0%. It significantly outperformed MMP-9, which reached 0.702, at P = .005.

HIF-1-alpha showed no diagnostic value at all, with an area under the curve of 0.453. It was, however, independently suppressed by smoking, at P = .007, which the authors frame as a marker of tobacco-driven hypoxia adaptation rather than of periodontal disease.

Bleeding on probing ran higher in the Grade B nonsmoker group at 44.6% than in the Grade C smoker group at 30.9%, though that difference did not reach statistical significance after Bonferroni correction, at P = .593.

The authors concluded that salivary MMP-8 offers adjunctive diagnostic value unaffected by the masking of gingival bleeding in heavy smokers, supporting its use 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