Characterizing the inflammation around dental implants: Bacterial infection, hypersensitivity, or both? A Feasibility study.
Heba Madi, Supervisor: Dr. Jocelyne Feine, Dr. Nicholas Makhoul, Dr. Giovanni Dibattista, Dr. Simon Tran.
Objective: This study aims to investigate cytokines and matrix metalloproteinase (MMPs) levels in periimplant crevicular fluid (PICF) associated with bacterial infection and hypersensitivity reaction in both healthy and inflamed dental implants.
Methods: A cross-sectional study is conducted at the Montreal General Hospital Oral and Maxillofacial clinic, involving individuals with at least one functional dental implant placed between 2010 and 2020. Clinical and radiological examinations are performed to classify implants as healthy or inflamed. PICF samples are collected from each implant and analyzed using the Human Luminex Assay to establish cytokine levels associated with bacterial infection (Type 1 and 3) and hypersensitivity (Type 2), as well as MMPs levels. Comparisons between healthy and inflamed implants were made and the relationship between cytokine/MMP levels and clinical diagnosis was investigated. Results: In this study, a total of 11 dental implants were examined, comprising 3 healthy implants, 7 implants with mucositis, and 2 implants with peri-implantitis. The analysis revealed a noticeable trend in cytokine levels, with the majority showing elevated levels in cases of mucositis and reaching their highest
levels in peri-implantitis. Specifically, the cytokines IL-4, IL-6, IL-13, IL-17, IL-23, TNF-α, IFN-γ, MMP-1, MMP-2, MMP-3, and MMP-13 exhibited this trend. It's worth noting that cytokines associated with hypersensitivity, namely IL-4 and IL-13, demonstrated a trend towards significance (IL-4, p=0.058; IL-13, p=0.30), while TNF-α and IFN-γ exhibited statistical significance (p=0.047). However, the remaining cytokines linked to bacterial infection did not display statistical significance among the three groups (IL-6, p=0.12; IL-17, p=0.65; IL-23, p=0.72). Notably, there were statistically significant differences in MMP-1 and MMP-2 between the groups (p=0.03 and p=0.01, respectively), while other MMPs, including MMP-3, MMP-9, and MMP-13, did not reach statistical significance (p=0.068, p=0.9, p=0.073, respectively Conclusion: This study investigates a comprehensive analysis of multiple cytokines and Matrix Metalloproteinases (MMPs) in peri-implant crevicular fluid (PICF) to enhance our understanding of the underlying inflammatory processes linked to peri-implant diseases. Additionally, the research aims to investigate the potential utility of these biomarkers, especially in relation to bacterial infections and hypersensitivity reactions, for the diagnosis and treatment of implant mucositis and peri-implantitis. It's important to note that the research topic, focusing on hypersensitivity to titanium dental implants, is relatively unexplored, and the study acknowledges its limitations. While a direct association between hypersensitivity and peri-implantitis hasn't been definitively established, the elevated levels of TNF-α, IFN-γ, MMP-1, and MMP-2, among other factors, strongly suggest the presence of inflammation around the implant, potentially contributing to tissue damage and collagen type IV degradation which is an important component of the extracellular matrix found in various tissues, including the gingiva.