title: Parameters of implant stability measurements based on resonance frequency and damping capacity: a comparative finite element analysis.
abstract: OBJECTIVE
  Contradictory results have been reported on the comparability of implant stability measurements performed with the Periotest and the Osstell Mentor devices. The purpose of the present finite element analysis was to simulate the influence of the parameters implant length, bone quality (cortical thickness and damping factor), bone loss, and quality of transducer fixation on resonance frequency analysis (RFA) and damping capacity measurements.
  
  
  METHODS
  Three-dimensional finite element models of implants placed in human mandibular bone were designed for the simulation of Periotest (Periotest value; PTV) and RFA (implant stability quotient) measurements. Three values for each of the parameters implant length, damping capacity of cortical and trabecular bone, thickness of cortical bone, bone loss, and quality of transducer fixation were obtained. Measurements were simulated at four stages of osseointegration.
  
  
  RESULTS
  For all parameters, an increase in implant stability was found with increasing levels of osseointegration. Implant stability was positively correlated with implant length and thickness of cortical bone, with slightly converging values at increased levels of osseointegration. Varying the damping factor of bone had no significant effect. Implant stability was negatively correlated with bone loss, with slightly converging values at increased levels of osseointegration. Linear changes in implant length and bone loss caused nonlinear effects in implant stability values. Stiffness of transducer fixation had an impact on RFA measurements when values below 10 GPa were applied.
  
  
  CONCLUSIONS
  Although both measuring devices reacted similarly when different parameters of implant stability were changed, good correlation between Periotest values and implant stability quotients was observed only when measurement values of implants without bone loss were considered.
authors.affiliation: Institute of Applied Mechanics, University of Erlangen-Nuremberg, Erlangen, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Winter
authors.forename: Stefan
authors.initials: S
authors.lastname: Möhrle
authors.forename: Stefan
authors.initials: S
authors.lastname: Holst
authors.forename: Matthias
authors.initials: M
authors.lastname: Karl
mesh_terms: D016301:Alveolar Bone Loss; D015519:Bone Density; D003198:Computer Simulation; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis / Q000379:methods*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D008954:Models, Biological; D016348:Osseointegration; D014159:Transducers; D014732:Vibration
chemical_list: D015921:Dental Implants