title: Bacterial Composition at the Implant-Abutment Connection under Loading in vivo.
abstract: OBJECTIVE
  Platform-switched implants have been demonstrated to prevent bone loss after loading. The present study evaluated bacterial composition of sites from implant-abutment connections of immediately loaded implants, which were placed in the anterior mandible. Ten patients participated in this study.
  
  
  METHODS
  A and B implant systems with two different prosthetic connections (Morse tapered vs internal polygonal butt-joint connections, respectively) were placed and loaded for 2 years. The abutments were removed (AB sample) after careful decontamination. Bacterial sampling of the abutments, inner part of the implants (before/visit 1 and after rinsing with chlorhexidine [CHX]/visit 2), and after new abutment connection and loading for 1 additional month, a new sampling (visit 3) was taken to compare the bacteria composition in association with the two connections. Bacterial profiles of samples were determined by using the human oral microbe identification microarray.
  
  
  RESULTS
  A total of 240 samples were analyzed taken at different time intervals. Nonparametric statistical analysis (Wilcoxon Rank sum) with uncorrected alpha (p < .05) and after corrections (Benjamini-Hochberg) found no statistical significance between the two connections. No significant changes in the overall microbial profiles were detected at the different time intervals. However, there were trends toward presence of periodontitis-associated species at the B implants in all samples (AB, visit 1, even after CHX irrigation) and after decontamination, abutment replacement, and 1-month loading period.
  
  
  CONCLUSIONS
  CHX irrigation does not seem to have any effect on decontamination of connections. As shown previously, there is significantly more bone loss around B implants compared with A implants. Although there was no statistical difference in the microbial profiles, there was indeed a trend for the presence of typical periodontal pathogens associated with the internal polygonal butt-joint connection. A possible scenario is that this connection tends to harbor the pathogens that may be involved in subsequent bone loss.
authors.affiliation: Eastman Institute for Oral Health, Department of Periodontology, University of Rochester, Rochester, NY, USA.
authors.forename: Georgios E
authors.initials: GE
authors.lastname: Romanos
authors.affiliation: Department of Dentistry, University of Rochester, Rochester, NY, USA.
authors.forename: Mary Therese
authors.initials: MT
authors.lastname: Biltucci
authors.affiliation: Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA.
authors.forename: Alexis
authors.initials: A
authors.lastname: Kokaras
authors.affiliation: Department of Microbiology, The Forsyth Institute, Cambridge, MA, USA.|Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, USA.
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Paster
mesh_terms: D000044:Dental Abutments / Q000382:microbiology*; D059605:Dental Implant-Abutment Design; D015921:Dental Implants / Q000382:microbiology*; D004926:Escherichia coli / Q000254:growth & development*; D006801:Humans; D066298:In Vitro Techniques; D018570:Risk Assessment; D013499:Surface Properties
chemical_list: D015921:Dental Implants
keywords: bacteria, immediate loading; implant-abutment interface; platform switching