RCT comparing minimally with moderately rough implants. Part 2: microbial observations

Background: Most current implants have a moderately rough surface (compared with older minimally rough turned implants) to facilitate osseointegration. This randomized controlled trial (RCT), with split-mouth design, examined whether this increased surface roughness influenced the initial subgingival plaque formation. Material and methods: Ten fully edentulous and eight partially edentulous patients, all with a history of severe periodontitis, received 4-6 implants (mandible or maxilla). Per jaw, both minimally (turned) and moderately rough (TiUnite) implants (MKIII; Nobel Biocare) were alternated. Also, the healing and final abutments had similar surface characteristics. Subgingival biofilm formation was followed up for 1 year, and samples were analyzed by culture technique, qPCR and checkerboard Results: Over the entire period, no statistically significant differences could be detected in subgingival microbiota between the minimally and moderately rough surfaces. In partially edentulous patients, the biofilm matured to a higher concentration of pathogens when compared with fully edentulous patients. The subgingival implant composition and concentration in partially edentulous patients were comparable to the subgingival microbiota along teeth. Conclusion: The roughness of the more modern implants did not influence the biofilm formation during the first year of implant loading.