title: Abutment Coating With Diamond-Like Carbon Films to Reduce Implant-Abutment Bacterial Leakage.
abstract: BACKGROUND
  The influence of diamond-like carbon (DLC) films on bacterial leakage through the interface between abutments and dental implants of external hexagon (EH) and internal hexagon (IH) designs was evaluated.
  
  
  METHODS
  Film deposition was performed by plasma-enhanced chemical vapor deposition. Sets of implants and abutments (n = 30 per group, sets of 180 implants) were divided according to connection design and treatment of the abutment base: 1) no treatment (control); 2) DLC film deposition; and 3) Ag-DLC film deposition. Under sterile conditions, 1 μL Enterococcus faecalis was inoculated inside the implants, and abutments were tightened. The sets were tested for immediate external contamination, suspended in test tubes containing sterile culture broth, and followed for 5 days. Turbidity of the broth indicated bacterial leakage. At the end of the period, the abutments were removed and the internal content of the implants was collected with paper points and plated in Petri dishes. After 24-hour incubation, they were assessed for bacterial viability and colony-forming unit counting. Bacterial leakage was analyzed by χ(2) and Fisher exact tests (α = 5%).
  
  
  RESULTS
  The percentage of bacterial leakage was 16.09% for EH implants and 80.71% for IH implants (P <0.0001). The bacterial load was higher inside IH implants (P = 0.000). The type of implant significantly influenced the results (P = 0.000), whereas the films did not (P = 0.487).
  
  
  CONCLUSIONS
  IH implants show a higher frequency of bacterial leakage; and DLC and Ag-DLC films do not significantly reduce the frequency of bacterial leakage and bacteria load inside the implants.
authors.affiliation: Dental School, Veiga de Almeida University (UVA), Rio de Janeiro, RJ, Brazil.
authors.forename: Mayra
authors.initials: M
authors.lastname: Cardoso
authors.affiliation: Graduate Program in Oral Biopathology and Department of Environmental Engineering, Institute for Science and Technology, São Paulo State University School of Dentistry (UNESP), São José dos Campos, Brazil.
authors.forename: Jorgiana
authors.initials: J
authors.lastname: Sangalli
authors.affiliation: Graduate Program in Oral Biopathology and Department of Environmental Engineering, Institute for Science and Technology, São Paulo State University School of Dentistry (UNESP), São José dos Campos, Brazil.
authors.forename: Cristiane Yumi
authors.initials: CY
authors.lastname: Koga-Ito
authors.affiliation: Aeronautics Institute of Technology, São José dos Campos, Brazil.
authors.forename: Leandro Lameirão
authors.initials: LL
authors.lastname: Ferreira
authors.affiliation: Aeronautics Institute of Technology, São José dos Campos, Brazil.
authors.forename: Argemiro Soares
authors.initials: AS
authors.lastname: da Silva Sobrinho
authors.affiliation: Department of Dental Materials and Prosthodontics, Institute for Science and Technology, São Paulo State University School of Dentistry, UNESP.
authors.forename: Lafayette
authors.initials: L
authors.lastname: Nogueira
mesh_terms: D002244:Carbon; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003763:Dental Leakage / Q000382:microbiology*; D017267:Dental Prosthesis Design; D018130:Diamond
chemical_list: D015921:Dental Implants; D002244:Carbon; D018130:Diamond
keywords: Bacterial load; Enterococcus faecalis; dental implants; microbial viability; microbiology; plasma gases