title: Correlation between microleakage and screw loosening at implant-abutment connection.
abstract: OBJECTIVE
  This study aimed to evaluate the correlation between microleakage and screw loosening at different types of implant-abutment connections and/or geometries measuring the torque values before and after the leakage tests.
  
  
  METHODS
  Three different abutment types (Intenal hex titanium, internal hex zirconium, morse tapered titaniuım) with different geometries were connected to its own implant fixture. All the abutments were tightened with a standard torque value then the composition was connected to the modified fluid filtration system. After the measurements of leakage removal torque values were re-measured. Kruskal-wallis test was performed for non-parametric and one-way ANOVA was performed for parametric data. The correlation was evaluated using Spearman Correlation Test (α=0.05).
  
  
  RESULTS
  Significantly higher microleakage was found at the connection of implant-internal hex zirconium abutment. Observed mean torque value loss was also significantly higher than other connection geometries. Spearman tests revealed a significant correlation between microleakage and screw loosening.
  
  
  CONCLUSIONS
  Microleakage may provoke screw loosening. Removing torque values rationally decrease with the increase of microleakage.
authors.affiliation: School of Health Services, Dental Prosthetics Technology, Hacettepe University, Ankara, Turkey.
authors.forename: Cem
authors.initials: C
authors.lastname: Sahin
authors.affiliation: Department of Prosthodontics, Center for Dental Sciences, Gulhane Military Medical Academy, Ankara, Turkey.
authors.forename: Simel
authors.initials: S
authors.lastname: Ayyildiz
keywords: Implant-abutment connection; Microleakage; Screw loosening