title: Distribution of peri-implant stresses with a countertorque device.
abstract: OBJECTIVE
  To verify the effectiveness of a countertorque device in dental implants in redistributing stress to the bone-implant interface during tightening of the abutment screw.
  
  
  METHODS
  Two prismatic photoelastic samples containing implants were made, one with a 3.75-mm-diameter implant and the other with a 5.0-mm-diameter implant (both implants had an external-hexagon interface) and the respective abutments were attached (CeraOne). The samples were placed in a support and submitted to torques of 10, 20, 32, and 45 Ncm with an electronic torque meter. The torque application was repeated 10 times on each sample (n = 10) with and without a countertorque device. Photoelastic patterns were detected; thus, a photographic register of each test was selected. The fringe patterns were analyzed at discrete points near the implants' external arch.
  
  
  RESULTS
  In both implants analyzed, a stress gradient reduction was observed through the implant with the countertorque device.
  
  
  CONCLUSIONS
  The countertorque device used in this study proved to be effective in reducing the stresses generated in the peri-implant bone tissue during torque application.
authors.affiliation: Department of Prosthodontics, School of Dentistry, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Claudio Luiz
authors.initials: CL
authors.lastname: Sendyk
authors.forename: Thais Torralbo
authors.initials: TT
authors.lastname: Lopez
authors.forename: Cleudmar Amaral
authors.initials: CA
authors.lastname: de Araujo
authors.forename: Wilson Roberto
authors.initials: WR
authors.lastname: Sendyk
authors.forename: Valdir Ferreira
authors.initials: VF
authors.lastname: Goncalvez
mesh_terms: D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D015921:Dental Implants; D003762:Dental Instruments; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods*; D004548:Elasticity; D013314:Stress, Mechanical; D019415:Torque
chemical_list: D015921:Dental Implants