title: Leakage of saliva through the implant-abutment interface: in vitro evaluation of three different implant connections under unloaded and loaded conditions.
abstract: OBJECTIVE
  Bacterial leakage along the implant-abutment interface, with consequent species harboring the inner parts of two-part dental implant systems, has been reported in the literature. The aim of this in vitro study was to evaluate bacterial leakage from human saliva to the internal part of the implants along the implant-abutment interface under loaded and unloaded conditions using DNA Checkerboard.
  
  
  METHODS
  Sixty dental implants--20 each of external-hexagon, internal-hexagon, and Morse cone-connection designs--and their conical abutments were used in this study. Each group was subdivided into two groups of 10 loaded and 10 unloaded implants. The assemblies were immersed in human saliva and either (1) loaded with 500,000 cycles at 120 N (experimental group) or (2) incubated in static conditions for 7 days at 35°C (unloaded control group).
  
  
  RESULTS
  Microorganisms were found in the internal surfaces of all types of connections. The Morse cone connection presented the lowest count of microorganisms in both the unloaded and loaded groups. Loaded implants presented with higher counts of microorganisms than unloaded implants for external- and internal-hex connections.
  
  
  CONCLUSIONS
  Bacterial species from human saliva may penetrate along the implant-abutment interface under both unloaded and loaded conditions for all connections evaluated. Morse cone-connection implants showed the lowest counts of microorganisms for both conditions. External- and internal-hex implants showed a higher incidence of bacteria and higher bacterial counts after simulated loading.
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Riberião Preto, University of São Paulo, Brazil.
authors.forename: Cássio
authors.initials: C
authors.lastname: do Nascimento
authors.forename: Paola Kirsten
authors.initials: PK
authors.lastname: Miani
authors.forename: Vinícius
authors.initials: V
authors.lastname: Pedrazzi
authors.forename: Reginaldo Bruno
authors.initials: RB
authors.lastname: Gonçalves
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
authors.forename: Adriana Cláudia Lapria
authors.initials: AC
authors.lastname: Faria
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Macedo
authors.forename: Rubens Ferreira
authors.initials: RF
authors.lastname: de Albuquerque
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000302:isolation & purification; D015169:Colony Count, Microbial; D003442:Crowns; D000044:Dental Abutments / Q000382:microbiology*; D059605:Dental Implant-Abutment Design; D015921:Dental Implants / Q000382:microbiology*; D003763:Dental Leakage; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D012463:Saliva / Q000382:microbiology; D018709:Statistics, Nonparametric; D054773:Streptococcus gordonii / Q000302:isolation & purification
chemical_list: D015921:Dental Implants