Peri-Implant Surgical Treatment Downregulates the Expression of sTREM-1 and MMP-8 in Patients with Peri-Implantitis: A Prospective Study

Abstract

sTREM-1 and its ligand PGLYRP1 play an essential role in the inflammatory process around teeth and implants. In this study, we aimed to evaluate the impact of peri-implant treatment on the salivary levels of the sTREM-1/PGLYRP-1/MMP-8 axis after 3 months. A total of 42 participants (with a mean age of 61 years old ± 7.3) were enrolled in this longitudinal study, 24 having peri-implant mucositis (MU) and 18 having peri-implantitis (PI). Clinical peri-implant parameters, such as probing pocket depth (PPD), % of plaque, and bleeding on probing (BOP), and the whole unstimulated saliva samples were evaluated at baseline and 3 months after treatment. The MU group received nonsurgical peri-implant treatment, while the PI group received open-flap procedures. The levels of sTREM-1, PGLYRP-1, MMP-8, and TIMP-1 were analyzed using enzyme-linked immunosorbent assays. BOP, plaque levels, and PPD significantly reduced after treatment in both groups. A significant decrease in the salivary levels of sTREM-1, MMP-8, and TIMP-1 in the PI group and PGLYRP1 and TIMP-1 in the MU group were observed. Salivary levels of sTREM-1 were significantly reduced in patients with PI but not with MU. Additionally, peri-implant treatment had a significantly higher impact on MMP-8 reduction in patients with PI than in those with MU.

Keywords: MMP-8; PGLYRP-1; peri-implant mucositis; peri-implant treatment; peri-implantitis; sTREM-1.

Figure 1

Levels of sTREM-1, PGLYRP-1, MMP-8, and TIMP-1 in saliva from individuals with peri-implant mucositis and peri-implantitis before and after treatment. p ≤ 0.05 (Wilcoxon signed-rank test).

Figure 2

The treatment effect variation in salivary levels of sTREM-1, PGLYRP1, MMP-8, and TIMP-1 from peri-implant mucositis patients and peri-implantitis expressed in Δ. p ≤ 0.05 (Mann–Whitney U test).

Figure 3

Ratio comparisons of total sTREM-1/PGLYRP-1, sTREM-1/MMP-8, and MMP-8/TIMP-1 in peri-implant mucositis patients and peri-implantitis patients at baseline and after peri-implant treatment. p ≤ 0.05 (Mann–Whitney U test).

Figure 4

Peri-implant treatment effects on the ratio of total sTREM-1/PGLYRP-1, sTREM-1/MMP-8, and MMP-8/TIMP-1 in peri-implant mucositis patients and peri-implantitis patients before and after peri-implant treatment. p ≤ 0.05 (Wilcoxon signed-rank test).

Figure 5

Heat maps exhibit correlations between the biomarkers and clinical parameters (a) and biomarkers (b) in saliva. * R ≥ 0.6, p ≤ 0.01 (Spearman correlation). PD: probing depth; BOP: bleeding on probing.