Histopathological and Immunohistochemical Study of Peri-Implant Epithelium

Background: Human beta-defensins (HBDs), epithelial-derived antimicrobial peptides, contribute to gingival health and periodontal disease. Particularly, the upregulation of HBD-3 expression in periodontal tissues is described to contribute to periodontal tissue regeneration. Specifically, the upregulation of HBD-3 expression in periodontal tissues is described to contribute to periodontal tissue regeneration. But there has been insufficient investigation of the inner epithelium in peri-implantitis, especially the HBD expression patterns as protection against oral infection. Objectives: The purpose of this study was to investigate the histopathological characteristics of the inner implant epithelium in peri-implantitis using histopathological and immunohistochemical methods and to compare it with the inner marginal epithelium in periodontitis. Materials and Methods: The biopsied cases consisted of 10 peri-implantitis, 11 periodontitis, and 10 controls. HE observation, measurement of the thickness of the inner epithelium, and immunohistochemical analysis for Ki-67 and HBD-3 were conducted. Results: Concerning the thickness of the inner epithelium, it was significantly higher in periodontitis (156.2 [138.0, 186.4] μm) than in peri-implantitis and control, 70.7 [67.5, 97.5] μm and 80.7 [76.6, 89.4] μm, respectively (p < 0.001). The Ki-67 positivity rates, both for inner epithelium and outer epithelium, were significantly higher in the following order: periodontitis, peri-implantitis, and control (p < 0.001). The inner epithelium is significantly elevated in the case of periodontitis (p < 0.001). For HBD-3, the intensity and region score (IRS) was significantly higher for inner epithelium than for outer epithelium (superficial layer) (p < 0.001) in all cases. The comparisons of IRS, significantly higher values were seen in inner epithelium of periodontitis than that of peri-implantitis (p < 0.001). Conclusion: Decreased production of HBD-3 in keratinocytes composing the inner implant epithelium may be one of the factors affecting tissue repair in peri-implantitis.