Characterization of macrophages infiltrating peri-implantitis lesions

Tobias Fretwurst, Carlos Garaicoa-Pazmino, Katja Nelson, William V. Giannobile, Cristiane H. Squarize, Lena Larsson, Rogerio M. Castilho

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Objectives: The mechanisms involved in the initiation and progression of peri-implantitis lesions are poorly understood. It was the aim to determine the content and activation status of macrophages present in human peri-implantitis lesions and compare the current findings with the macrophage polarization associated with periodontitis lesions. Material and Methods: A total of 14 patients were studied in this investigation. Seven were soft tissue biopsies from dental implants affected by peri-implantitis that required explantation. Seven biopsies were from chronic periodontal disease. Immunofluorescence stains were performed using biomarkers to identify macrophages (CD68+) undergoing M1 polarization (iNOS+) and M2 polarization (CD206+), along with Hoechst 33,342 to identify DNA content. All samples were stained and photographed, and double-positive cells for CD68 and iNOS or CD68 and CD206 were quantified. Results: All peri-implantitis biopsies examined revealed a mixed population of macrophages undergoing M1 polarization and M2 polarization. Further analysis demonstrated the co-expression of iNOS and CD206, which indicates the presence of a heterogenic immune response on peri-implantitis lesions. Macrophage polarization in peri-implantitis lesions presents a distinct pattern than in periodontitis. We observed a significant increase in the population of M1 macrophages on peri-implantitis samples compared to periodontal disease samples. Conclusion: Our results demonstrate that peri-implantitis has higher numbers of macrophages displaying a distinct macrophage M1 polarization signature compared to periodontitis lesions. This pattern may explain, in part, the distinct nature of peri-implantitis progression vs. periodontitis in humans.

Original languageEnglish (US)
Pages (from-to)274-281
Number of pages8
JournalClinical Oral Implants Research
Issue number3
StatePublished - Mar 1 2020


  • Peri-implantitis
  • dental implants
  • histology
  • inflammation
  • macrophages
  • nitric oxide synthase
  • periodontitis

ASJC Scopus subject areas

  • Oral Surgery


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