Date of Award

2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Stomatology

College

College of Dental Medicine

First Advisor

Oziem Yilmaz

Second Advisor

Michael Cuenin

Third Advisor

Zachary P. Evans

Abstract

The Objective: The present study aimed to evaluate the presence of periodontal pathogens P. gingivalis, F. nucleatum, and F. alocis in gingival biopsies of patients with health, periodontitis, or peri-implantitis. Background: P. gingivalis, F. nucleatum, and F. alocis are periodontal pathogens implicated in diseases of the periodontium and peri-implant tissue. Purinergic signaling is a complex network of small molecular messengers and receptors that elicit agonistic/antagonistic actions on the immune response during infection. P. gingivalis secretes an effector molecule, nucleoside-diphosphate-kinase (Ndk), which has been shown to impact the host purinergic signaling cascade to facilitate chronic infection. Materials and Methods: An observational cross-sectional study was conducted on patients diagnosed with periodontal health, chronic periodontitis, and peri-implantitis that needed dental surgical treatment. Gingival tissue biopsy specimens were collected at the time of dental surgery. Immunofluorescence was conducted to observe the presence and localization of target bacteria, comparing healthy, periodontitis, and peri-implantitis patients. Immunohistochemical analysis was completed to detect and observe P. gingivalis Ndk expression in gingival biopsies. Results: 35 gingival/mucosal biopsies were gathered from 28 patients: seven healthy, ten periodontitis, and ten peri-implantitis. Immunofluorescence imaging showed presence of all three species in periodontitis and peri-implantitis patient samples. All three species appear to accumulate pre-dominantly in the basal layer of the epithelium, however bacteria were also detected in deeper tissue layers. P. gingivalis Ndk was observed more intensely in periodontitis and peri-implantitis samples. Conclusion: P. gingivalis, F. nucleatum, and F. alocis were found in tissue samples of periodontitis and peri-implantitis patients. This is the first time F. alocis has been reported to be microscopically observed in human gingival tissue. P. gingivalis Ndk was also observed in tissue from periodontitis and peri-implantitis groups, suggesting it may play a role in periodontal and peri-implant disease processes.

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