Salivary biomarkers of periodontal disease in response to treatment

Abstract

Background: Salivary biomarkers of periodontitis were assessed longitudinally to determine response to therapy.

Methods: A 6-month case-controlled study of adults with chronic periodontitis was performed, with 33 participants receiving oral hygiene instructions (OHI) alone and 35 with scaling and root planing (SRP) combined with OHI. Saliva samples collected at week 0, 16 and 28 were analysed for interleukin (IL)-1β, IL-8, macrophage inflammatory protein (MIP)-1α, matrix metalloproteinase-8 (MMP-8), osteoprotegerin (OPG), and tumour necrosis factor-α (TNF)-α. Clinical measures of periodontal disease were recorded at each visit.

Results: All parameters of periodontal health improved significantly in both groups by week 16 (p<0.0001) with the SRP group demonstrating greater benefit at week 16 and 28. Baseline OPG and TNF-α levels changed significantly at both follow-up visits (p<0.03), regardless of treatment group. IL-1β and MMP-8 levels decreased significantly from baseline (p<0.04) in the SRP group only. OPG, MMP-8, and MIP-1α were significantly reduced in responders compared with non-responders (p=0.04, 0.01, 0.05, respectively). In receiver-operating characteristic analyses, MMP-8 produced the highest area under the curve (0.7; p=0.01).

Conclusion: Salivary levels of IL-1β, MMP-8, OPG, and MIP-1α reflected disease severity and response to therapy suggesting their potential utility for monitoring periodontal disease status.

Figure 1

Clinical periodontal measures by group and visit. A) OHI and B) SRP. Significant reductions (p<0.0001) occurred in each parameter compared to baseline within groups as determined by ANCOVA.

Figure 2

Boxplots of biomarkers by group and visit. A) IL-1β, B) IL-8, C) MIP-1α, D) MMP-8, E) OPG, and F) TNF-α. Left three boxes correspond to OHI and right three boxes for SRP. Horizontal lines represent the 25^th, 50^th and 75^th percentiles, plus sign represents the mean, and filled circles represent outliers and * indicates outliers clipped from boxplot. X-axis corresponds with weeks.

Figure 3

Boxplots of change scores of biomarkers (log values) at week 28 by group and responder status. Left two boxes correspond to non-responder and right boxes to responders. Significant p-values for comparing responders to non-responders are indicated on the plots.