title: Manual closing torque in five implant abutment systems: an in vitro comparative study.
abstract: OBJECTIVE
  A significant percentage of abutment/implant (A/I) assemblies tend to unscrew on functional loading.
  
  
  OBJECTIVE
  This in vitro study evaluated the maximum closing torque generated manually for comparison with recommended closing torque values in 5 implant systems.
  
  
  METHODS
  Closing torque generated by 9 operators with 5 manual torque drivers was measured and compared by using a mannequin and torque gauge assembly.
  
  
  RESULTS
  Closing torque values were found to be significantly different between operators and between implant systems (P <.0001). Mean closing torque values of 9 operators performing 5 closures for 5 systems ranged from 7 to 14.6 N/cm for habitual closures and from 9.4 to 19.9 N/cm for maximum closures.
  
  
  CONCLUSIONS
  The results demonstrated that maximum manual closure did not approach recommended closing torque in any of the system measured. Significant interoperator and intraoperator variability was found in the closing torque with manual drivers, and the driver diameter and grip were probably an important feature in the generation of high closing torque.
authors.affiliation: The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel. grossmd@post.tau.ac.il
authors.forename: M
authors.initials: M
authors.lastname: Gross
authors.forename: D
authors.initials: D
authors.lastname: Kozak
authors.forename: B Z
authors.initials: BZ
authors.lastname: Laufer
authors.forename: E I
authors.initials: EI
authors.lastname: Weiss
mesh_terms: D000704:Analysis of Variance; D000044:Dental Abutments; D015921:Dental Implants; D017267:Dental Prosthesis Design / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D008953:Models, Anatomic; D015588:Observer Variation; D013314:Stress, Mechanical; D019415:Torque
chemical_list: D015921:Dental Implants