title: Different sealing materials preventing the microbial leakage into the screw-retained implant restorations: an in vitro analysis by DNA checkerboard hybridization.
abstract: OBJECTIVE
  The aim of this controlled in vitro study was to identify and quantify up to 38 microbial species penetrating through the screw-retained implant prostheses with different sealing materials.
  
  
  METHODS
  Sixty morse cone implants were restored with single-unit screw-retained prostheses. All the components were randomly divided into five groups (n = 12) according to the proposed materials: (1) polytetrafluoroethylene tape+composite resin; (2) polytetrafluoroethylene tape+gutta-percha; (3) polytetrafluoroethylene tape+light-polymerized provisional composite; (4) cotton pellet+gutta-percha; and (5) cotton pellet+light-polymerized provisional composite. Human saliva was used as contaminant media, and DNA checkerboard hybridization was used to identify and quantify microbial species.
  
  
  RESULTS
  Microbial leakage was observed in all groups: M. salivarium, S. pasteuri, P. nigrescens, and P. melaninogenica were the species presenting the highest values of genome count, prevalence, and proportion within the groups. The total microbial mean counts (×105, ±SD) were as follows: Group 1 (2.81 ± 0.38), Group 2 (3.41 ± 0.38), Group 3 (6.02 ± 1.48), Group 4 (6.40 ± 1.42), and Group 5 (17.45 ± 1.67). Group 5 showed the higher microbial counts (P < 0.001).
  
  
  CONCLUSIONS
  Moderate to high counts of pathogenic/nonpathogenic species were detected in the inner parts of implants from all groups. The lowest values of microbial counts were recorded for polytetrafluoroethylene tape associated with composite resin or gutta-percha; cotton pellet associated with light-polymerized provisional composite presented the highest microbial counts.
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Cássio
authors.initials: C
authors.lastname: do Nascimento
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Murillo Sucena
authors.initials: MS
authors.lastname: Pita
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Paulo Linares
authors.initials: PL
authors.lastname: Calefi
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Thalisson Saymo
authors.initials: TS
authors.lastname: de Oliveira Silva
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Juliane Bustamante Sá
authors.initials: JB
authors.lastname: Dos Santos
authors.affiliation: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Vinícius
authors.initials: V
authors.lastname: Pedrazzi
mesh_terms: D000328:Adult; D001863:Bone Screws; D003188:Composite Resins; D032561:Cotton Fiber; D015921:Dental Implants / Q000382:microbiology*; D003763:Dental Leakage / Q000517:prevention & control*; D006171:Gutta-Percha; D006801:Humans; D066298:In Vitro Techniques; D009693:Nucleic Acid Hybridization / Q000379:methods*; D011138:Polytetrafluoroethylene; D012463:Saliva / Q000382:microbiology*
chemical_list: D003188:Composite Resins; D015921:Dental Implants; D006171:Gutta-Percha; D011138:Polytetrafluoroethylene
keywords: DNA checkerboard; bacteria; dental implants; microleakage; prosthodontics