The microbiota associated with implants restored with platform switching: a preliminary report

Background: It was demonstrated that implants restored according to a platform-switching concept presented less crestal bone loss than implants restored with standard protocols. The aim of this study is to examine differences between the composition of the peri-implant microbiotas associated with implants restored with the platform-switching approach and implants restored with a standard internal connection protocol. Methods: A total of 48 implants were examined in 18 subjects: 33 implants were restored with platform switching, and 15 implants were restored using the traditional approach. Thirty-six months after prosthetic loading, subgingival plaque samples were taken from the mesio- and disto-buccal aspects of each implant and from one tooth adjacent to one of the implants in each subject. The levels of 40 subgingival species were measured using checkerboard DNA-DNA hybridization. Microbiologic parameters were averaged within each subject and across subjects in each clinical group (platform switching versus control) and site category (implants versus teeth) separately. The significance of differences between clinical groups and site categories was determined using the Mann-Whitney test and the Wilcoxon test, respectively. Results: There were no statistically significant differences between groups for any of the species. The platform-switching group showed a small trend for lower levels of early colonizer members of the Actinomyces, purple and yellow complexes, Campylobacter species, Tannerella forsythia (previously T. forsythensis), and Porphyromonas gingivalis. Teeth and implants presented similar microbial profiles. Conclusion: The results of the study suggest that the difference in bone crest resorption between implants restored with platform switching compared to traditionally restored implants is not associated with differences in the peri-implant microbiota