title: Primary Stability of Cylindrical and Conical Dental Implants in Relation to Insertion Torque-A Comparative Ex Vivo Evaluation.
abstract: BACKGROUND
  The aim of this ex vivo study was to investigate the influence of different insertion torques on primary stability of a conical and a cylindrical implant system.
  
  
  METHODS
  Thirty-two dental implants (Astra Tech OsseoSpeed 5.0 S × 11 mm cylindrical [n = 16] and 5.0 × 11 mm conical [n = 16]) were inserted with 20, 30, 40, and 45 N·cm into fresh porcine bone of mixed trabecular-cortical quality. Before insertion, bone quality was assessed via cone beam tomography. After insertion, resonance frequency analysis was reported using the implant stability quotient (ISQ). Implant insertion depths were evaluated, and the implants were pushed out of the bone by force (measured in N). All experiments were done with n = 4 per group.
  
  
  RESULTS
  The highest ISQ (mean 78.25 ± 2.9) and pushout values (mean 675 N ± 5.8) were measured for the cylindrical implant after insertion using 30 N·cm. The conical implant showed the highest primary stability by means of ISQ (mean 76.25 ± 2.2) and pushout force (mean 502.5 N ± 9.6) after an insertion torque of 40 N·cm. If more insertion force was used, primary stability was reduced in all cases.
  
  
  CONCLUSIONS
  The data indicate that different forms of an implant system need different insertion torques to obtain an optimal primary stability. These results have to be verified clinically.
authors.affiliation: *Employee, Private Dental Praxis Dr. Rossa, Ludwigshafen, Germany. †Scientific Researcher, Laboratory of Tissue Engineering, State University of Medicine and Pharmacy "N. Testemitanu," Chisinau, Moldova. ‡Employee, Private Dental Praxis Dr. Rossa, Ludwigshafen, Germany. §Consultant, Department of Prosthodontics and Materials Science, University of Rostock, Germany. ¶Associate Professor, Department of Prosthetic Dentistry, University Medical Centre Mainz, Germany. ‖Professor, Department of Prosthodontics and Materials Science, University of Rostock, Germany. #Assistant Medical Director and Associate Professor, Department of Oral, Maxillofacial and Plastic Surgery, University Medical Center Rostock, Rostock, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Staedt
authors.forename: Victor
authors.initials: V
authors.lastname: Palarie
authors.forename: Arne
authors.initials: A
authors.lastname: Staedt
authors.forename: Jens M
authors.initials: JM
authors.lastname: Wolf
authors.forename: Karl Martin
authors.initials: KM
authors.lastname: Lehmann
authors.forename: Peter
authors.initials: P
authors.lastname: Ottl
authors.forename: Peer W
authors.initials: PW
authors.lastname: Kämmerer
mesh_terms: D000818:Animals; D054893:Cone-Beam Computed Tomography; D003757:Dental Implantation / Q000009:adverse effects / Q000379:methods*; D015921:Dental Implants / Q000009:adverse effects; D017268:Dental Prosthesis Retention / Q000009:adverse effects / Q000379:methods*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D013552:Swine; D019415:Torque
chemical_list: D015921:Dental Implants