Primary stability, insertion torque, and bone density of conical implants with internal hexagon: Is there a relationship?

Paolo Trisi, Davide Berardi, Michele Paolantonio, Giuseppe Spoto, Antonio D'Addona, Giorgio Perfetti

Research output: Contribution to journalArticle

18 Citations (Scopus)


Between implants and peri-implant bone, there should be a minimum gap, without micromotions over a threshold, which could cause resorption and fibrosis. The higher the implant insertion torque, the higher will be the initial stability. The aim was to evaluate in vitro the correlation between micromotions and insertion torque of implants in bone of different densities. The test was performed on bovine bone of hard, medium, and soft density: 150 implants were used, 10 for each torque (20, 35, 45, 70, and 100 N/cm). Samples were fixed on a loading device. On each sample, we applied a 25-N horizontal force. Insertion torque and micromotions are statistically correlated. In soft bone with an insertion force of 20 and 35 N/cm, the micromotion resulted significantly over the risk threshold, which was not found with an insertion force of 45 and 70 N/cm and in hard and medium bones with any insertion torque. The increase in insertion torque reduces the amount of micromotions between implant and bone. Therefore, the immediate loading may be considered a valid therapeutic choice, even in low-density bone, as long as at least 45 N/cm of insertion torque is reached. Copyright © 2013 by Mutaz B. Habal, MD.
Original languageEnglish
Pages (from-to)841-844
Number of pages4
Publication statusPublished - 2013


  • Animals
  • Biomechanical Phenomena
  • Bone Density
  • Bone density
  • Cattle
  • Dental Implantation, Endosseous
  • Dental Implants
  • Dental Prosthesis Design
  • Dental Prosthesis Retention
  • Dental Stress Analysis
  • Immediate loading
  • Insertion torque
  • Materials Testing
  • Micromovements
  • Otorhinolaryngology2734 Pathology and Forensic Medicine
  • Primary stability
  • Stress, Mechanical
  • Surgery
  • Torque


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