title: The Pathogenesis of Implant-Related Reactive Lesions: A Clinical, Histologic and Polarized Light Microscopy Study.
abstract: Peri-implant soft tissue reactive lesions (I-RLs) may jeopardize implant success and survival. To the best of the authors' knowledge, its pathogenesis is unknown. The objective of this study is to conduct a clinicopathologic and polarized light microscopy (PLM) analysis of 14 new I-RLs and compare them with comparable tooth-associated cases (T-RLs) to better understand I-RL pathogenesis.
  
  
  
  Fifty-eight new cases of I-RL and T-RL were retrieved from the pathology department archives of Rambam Health Care Campus, Haifa, Israel. Retrospective analysis of histopathologic and clinical features was conducted, documented, and then compared for: 1) I-RL (n = 14), 2) peri-implant pyogenic granuloma (I-PG) (n = 5), 3) peri-implant peripheral giant cell granuloma (I-PGCG) (n = 9), 4) T-RL (n = 44), 5) tooth-associated pyogenic granuloma (T-PG) (n = 21), and 6) tooth-associated peripheral giant cell granuloma (T-PGCG) (n = 23). Presence of foreign bodies was assessed using PLM.
  
  
  
  Foreign bodies were found more commonly in I-RLs (n = 13/14; 93%) when compared with T-RLs (n = 18/44; 41%), which was a statistically significant difference (P = 0.01) with an odds ratio of 7.9. Microscopically, I-PGCG was associated with: 1) lower multinucleated giant cell count (P = 0.04); 2) lower density of mesenchymal cells (P = 0.05); and 3) more diffuse, non-lobulated stromal morphology (P = 0.001). Clinically, I-RLs were found in patients who were older, and all cases were located in the posterior region: mandible (n = 12/14; 86%) and maxilla (n = 2/14; 14%).
  
  
  
  In cases of implant failure, implantation of foreign bodies may play a role with subsequent development of I-PG and I-PGCG-like lesions. Clinicians should be aware of this risk so they can implement measures to minimize adverse implant outcomes.
authors.affiliation: Department of Periodontology, School of Graduate Dentistry, Rambam Health Care Campus, Haifa, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Halperin-Sternfeld
authors.affiliation: Department of Pathology, Rambam Health Care Campus.|Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.
authors.forename: Edmond
authors.initials: E
authors.lastname: Sabo
authors.affiliation: Department of Pathology, Rambam Health Care Campus.|Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel.|Department of Oral and Maxillofacial Surgery, Rambam Health Care Campus.
authors.forename: Sharon
authors.initials: S
authors.lastname: Akrish
mesh_terms: D015921:Dental Implants; D005882:Gingival Diseases / Q000000981:diagnostic imaging*; D006801:Humans; D007557:Israel; D008859:Microscopy, Polarization; D012189:Retrospective Studies
chemical_list: D015921:Dental Implants
keywords: Dental implants; foreign-body reaction; granuloma, giant cell; granuloma, pyogenic