Background: The analysis of biomarkers in gingival crevicular fluid (GCF) may be helpful in forecasting patient vulnerability to future attachment loss. The purpose of this study is to correlate GCF biomarkers of inflammation and bone resorption with subsequent periodontal attachment and bone loss in a longitudinal trial of a matrix metalloproteinase (MMP) inhibitor.
Methods: GCF was collected from two periodontal pockets (mean +/- SD: 5.1 +/- 1.0 mm) at baseline and annually in postmenopausal females with moderate to advanced periodontitis undergoing periodontal maintenance every 3 to 4 months during a 2-year double-masked, placebo-controlled, randomized clinical trial of subantimicrobial dose doxycycline (SDD; 20 mg two times a day). Subjects were randomized to SDD (n = 64) or a placebo (n = 64). GCF was analyzed for the inflammation markers interleukin (IL)-1beta (using enzyme-linked immunosorbent assay), total collagenase activity (using hydrolysis of a synthetic octapeptide), and MMP-8 (using a Western blot) and the bone-resorption marker carboxyterminal telopeptide cross-link fragment of type I collagen (ICTP) (using a radioimmunoassay). Generalized estimating equations were used to associate these biomarkers, categorized into tertiles, with subsequent clinical attachment (using an automated disk probe) or interproximal bone loss (using radiography). Odds ratio (OR) values compared highest to lowest tertile groups.
Results: Increases in GCF IL-1beta and MMP-8 during the first year of periodontal maintenance were associated with increased odds of subsequent (year 2) periodontal attachment loss (OR = 1.67; P = 0.01 and OR = 1.50; P = 0.02, respectively) driven by the placebo group. Elevated baseline ICTP was also associated with increased odds of 1- and 2-year loss of alveolar bone density (OR = 1.98; P = 0.0001) in the placebo group, not the SDD group, and a loss of bone height (OR = 1.38; P = 0.06), again driven by the placebo group.
Conclusion: These data support the hypothesis that elevated GCF biomarkers of inflammation and bone resorption from a small number of moderate/deep sites have the potential to identify patients who are vulnerable to progressive periodontitis, and SDD may modify that risk.