title: Influence of simulated bone-implant contact and implant diameter on secondary stability: a resonance frequency in vitro study.
abstract: OBJECTIVE
  This study tested the hypothesis of no differences in resonance frequency for standardized amounts of simulated bone-implant contact around implants with different diameters. In addition, it was evaluated if resonance frequency is able to detect a difference between stable and rotation mobile ("spinning") implants.
  
  
  METHODS
  Implants with diameters of 3.3, 4.1 and 4.8 mm were placed in a purposely designed metal mould where liquid polyurethane resin was then poured to obtain a simulated bone-implant specimen. By regulating the mould, it was possible to create the following simulated bone-implant contact groups: 3.3 mm (198.6 mm(2)); 4.1 mm (198.8 mm(2)); 4.8 mm (200.2 mm(2)); 4.8 mm (231.7 mm(2)); 4.8 mm (294.7 mm(2)). Each group included 10 specimens. After resin setting, resonance frequency was measured. On the last group, measurements were repeated after establishing implant rotational mobility. One-way ANOVA tests with post hoc comparisons, a Pearson's correlation coefficient and a t-test for repeated measurements were used to evaluate statistically significant differences.
  
  
  RESULTS
  Implants with different diameters but with the same amount of simulated osseointegration revealed no differences in resonance frequency. On the contrary, an increase of simulated bone-implant contact resulted in significantly higher resonance frequency. A clear direct linear correlation resulted between resonance frequency and simulated bone-implant contact. Furthermore, a significant difference resulted between resonance frequency measured before and after creation of rotational mobility.
  
  
  CONCLUSIONS
  Within the conditions of this study, the secondary stability was correlated with the simulated bone-implant contact. In addition, resonance frequency was able to discern between stable and rotation mobile implants.
authors.affiliation: Specialist Clinic for Periodontology, Göteborg, Sweden.
authors.forename: Mario
authors.initials: M
authors.lastname: Veltri
authors.forename: Oscar
authors.initials: O
authors.lastname: González-Martín
authors.forename: Urs C
authors.initials: UC
authors.lastname: Belser
mesh_terms: D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D066298:In Vitro Techniques; D008422:Materials Testing; D008953:Models, Anatomic; D013499:Surface Properties; D014732:Vibration
chemical_list: D015921:Dental Implants
keywords: dental implants; implant diameter; osstell; secondary stability