title: Evaluation of the correlation between insertion torque and primary stability of dental implants using a block bone test.
abstract: OBJECTIVE
  Implant stability at the time of surgery is crucial for the long-term success of dental implants. Primary stability is considered of paramount importance to achieve osseointegration. The purpose of the present study was to investigate the correlation between the insertion torque and primary stability of dental implants using artificial bone blocks with different bone densities and compositions to mimic different circumstances that are encountered in routine daily clinical settings.
  
  
  METHODS
  In order to validate the objectives, various sized holes were made in bone blocks with different bone densities (#10, #20, #30, #40, and #50) using a surgical drill and insertion torque together with implant stability quotient (ISQ) values that were measured using the Osstell Mentor. The experimental groups under evaluation were subdivided into 5 subgroups according to the circumstances.
  
  
  RESULTS
  In group 1, the mean insertion torque and ISQ values increased as the density of the bone blocks increased. For group 2, the mean insertion torque values decreased as the final drill size expanded, but this was not the case for the ISQ values. The mean insertion torque values in group 3 increased with the thickness of the cortical bone, and the same was true for the ISQ values. For group 4, the mean insertion torque values increased as the cancellous bone density increased, but the correlation with the ISQ values was weak. Finally, in group 5, the mean insertion torque decreased as the final drill size increased, but the correlation with the ISQ value was weak.
  
  
  CONCLUSIONS
  Within the limitations of the study, it was concluded that primary stability does not simply depend on the insertion torque, but also on the bone quality.
authors.affiliation: Department of Periodontology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Korea.
authors.forename: Dorjpalam
authors.initials: D
authors.lastname: Bayarchimeg
authors.forename: Hee
authors.initials: H
authors.lastname: Namgoong
authors.forename: Byung Kook
authors.initials: BK
authors.lastname: Kim
authors.forename: Myung Duk
authors.initials: MD
authors.lastname: Kim
authors.forename: Sungtae
authors.initials: S
authors.lastname: Kim
authors.forename: Tae-Il
authors.initials: TI
authors.lastname: Kim
authors.forename: Yang Jo
authors.initials: YJ
authors.lastname: Seol
authors.forename: Yong Moo
authors.initials: YM
authors.lastname: Lee
authors.forename: Young
authors.initials: Y
authors.lastname: Ku
authors.forename: In-Chul
authors.initials: IC
authors.lastname: Rhyu
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Lee
authors.forename: Ki-Tae
authors.initials: KT
authors.lastname: Koo
keywords: Bone density; Dental implants; Torque