UBC Theses and Dissertations
Scanning electron microscopy analysis of biofilm on dental implants explanted due to peri-implantitis Chang, Jae Wook
Background: About 20% of subjects receiving implants develop peri-implantitis (PI) that associates with progressive inflammation and bone loss around implants, often leading to implant failure. PI is caused by bacteria that accumulate in peri-implant space but the consensus on microbial profile is still lacking. Microbial sampling of PI lesions has largely focused on analyzing bacterial species that have been shed from implant surface and captured in the pocket fluid. The purpose of the present study was to investigate the morphotypes of bacteria in microbial ecosystem that covers the implant threads and explore whether different brands of implants favor different morphotypes and whether certain morphotypes were associated with more advanced disease. Methods: The implants (N=14) that were determined to have failed by the clinician were removed and instantly processed for scanning electron microscope analysis. The implants were imaged at three equally divided levels of the exposed area due to diseased bone loss. Bacterial morphotypes [cocci, rods, filaments, spirilla/spirochetes] in each level were further analyzed at higher magnification to enable identification and quantification by three examiners. The different types of surfaces, mobility and years in functions were correlated to the presence of specific morphotypes. Results: Implants removed due to PI demonstrated the presence of variable bacterial morphotypes that did not correlate to disease progression in our preliminary study. Some implants were dominated by filaments and others showed the presence of combinations of cocci and rods or mixed morphotypes of spirilles/spirochetes. Rods and filaments were dominant species throughout the surfaces and cocci showed increased presence towards the apical third compared to coronal and middle thirds. There were significant differences in the morphotypes in the implants with TiUnite and SLA surfaces (except for cocci), with mobility and with more than 10 years of function. Conclusions: The profiles of morphotypes in biofilms of different implants with similar clinical presentation of PI were highly variable and did not clearly associate with implant brand. While there were significant differences between implants, interestingly, similar morphotypes on individual implants were found throughout the entire implant surface.
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