title: Effect of fluid contamination on reverse torque values in bone-level implants.
abstract: BACKGROUND
  Screw loosening is one of the most common mechanical complications within the prosthetic components of dental implants. Clinicians must know if reverse torque values (RTVs) are affected by contamination of the implant abutment screw hole with either blood, saliva or chlorhexidine.
  
  
  METHODS
  Forty implants were divided into 4 groups (n = 10). Implants were embedded in epoxy resin and placed in a digital torque meter. Screw holes of 30 implants were contaminated with either chlorhexidine (CG), fresh human saliva (SG), or blood (BG), and the remaining noncontaminated screws served as a control group (NC). Abutment screws were tightened using a hand-held torque meter (25 N·cm). Thermocycling (1500 cycles) was performed, and abutment detorque values were calculated using the digital torque meter.
  
  
  RESULTS
  RTVs were lower than insertion torque values for all groups. According to Tukey HSD Test, blood contamination of abutment screws resulted in significantly lower RTVs (18.950 ± 2.641 N·cm) when compared with controls.
  
  
  CONCLUSIONS
  Blood contamination of abutment screw holes was shown to significantly decrease RTVs. Blood contamination may result in greater loosening of implant screws in clinical practice.
authors.affiliation: *Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey. †Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey. ‡Research Assistant, Department of Prosthodontics, Faculty of Dentistry, Erciyes University, Kayseri, Turkey. §Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Pamukkale University, Denizli, Turkey.
authors.forename: Hasan O
authors.initials: HO
authors.lastname: Gumus
authors.forename: Mustafa
authors.initials: M
authors.lastname: Zortuk
authors.forename: Haydar
authors.initials: H
authors.lastname: Albayrak
authors.forename: Mehmet
authors.initials: M
authors.lastname: Dincel
authors.forename: Hasan H
authors.initials: HH
authors.lastname: Kocaagaoglu
authors.forename: Halil I
authors.initials: HI
authors.lastname: Kilinc
mesh_terms: D016025:Bone Transplantation; D019415:Torque