Different sealing materials preventing the microbial leakage into the screw-retained implant restorations: an in vitro analysis by DNA checkerboard hybridization.

ObjectivesThe aim of this controlled invitro study was to identify and quantify up to 38 microbial species penetrating through the screw-retained implant prostheses with different sealing materials. Material and methodsSixty 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. ResultsMicrobial 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 (x10(5), 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). ConclusionsModerate 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.