• implant stability quotient;
  • Osstell™;
  • Osstell Mentor™;
  • implant stability;
  • reproducibility


The aim of this study was to assess the primary stability of dental implants by resonance frequency analysis (RFA) using the Osstell™ and Osstell Mentor™ devices and to investigate the reproducibility and comparability of the results obtained with these devices. Twenty-four Straumann implants (Straumann AG, Basel, Switzerland) were placed in the anterior mandible of 12 fresh edentulous human cadaver mandibles. The implant stability quotients (ISQs) were measured with the Osstell™ and Osstell Mentor™ when implants were inserted at 50% of their length and following their complete insertion. The Osstell™ device measured lower scores compared with the Osstell Mentor™. This was significant for the full position (mean difference = 9·9), t (11) = 7·4, < 0·001 and for the halfway position (mean difference = 5·9), t (11) = 2·41, = 0·03. In con-clusion, the Osstell™ produced relatively lower ISQ scores than the Osstell Mentor™.