Thesis (M.Sc.)--Chulalongkorn University, 2012

Objective To investigate the putative pathogenic bacteria, Porphyromonas gingivalis (Pg), Treponema denticola (Td), or Tanerella forsythia (Tf ), associating with implant-supported dental prostheses using differential transmucosal designs. Methodology Forty-five partially edentulous patients who received implant-supported fixed partial prostheses were randomly selected and categorized into three groups based on the transmucosal implant-abutment connections, including the platform-matching abutments (n = 15), platform-switching abutments (n = 15), and tissue-level dental implants (n = 15). To obtain subgingival bacterial samples, four paper points were inserted under light pressure in healthy peri-implant sulci, and DNA was extracted from the samples. Pg-, Td-, or Tf -specific DNA was detected by endpoint PCR. Results There was no statistically significant differences (P > 0.05) in the frequencies of the Pg, Tf, or Td associating with differential transmucosal designs under healthy conditions. However, the proportion of Tf associating with platform-matching abutments or platform-switching abutments was substantially higher than Pg or Td. The chi-square test showed significant differences (P < 0.05) in the frequencies of these bacteria in the groups restored with platform-matching abutments or platform-switching abutments, but not tissue-level dental implants. Conclusion periodontal pathogens are part of the normal resident microbiota and may be found at healthy peri-implant sites.