Geckili O, Bilhan H, Cilingir A, Mumcu E, Bural C. A comparative in vitro evaluation of two different magnetic devices detecting the stability of osseo-integrated implants. J Periodont Res 2012; 47: 508513. (c) 2012 John Wiley & Sons A/S Background and Objective: It is unknown whether the resonance frequency analysis (RFA) measurements made by two different magnetic resonance frequency analysers are comparable. This in vitro study was designed to compare the RFA measurements made by the two magnetic resonance frequency analysers and to evaluate the intra- and interobserver reliability of the magnetic devices. Material and Methods: Thirty-two implants were placed in four cow ribs. The RFA value of each implant was measured by five different examiners. The measurements were repeated five times, in both the buccal and mesial directions, for each implant at 2 h intervals, and the averages of registered implant stability quotient (ISQ) units were recorded as the buccal ISQ value and the mesial ISQ value for every implant. Results: No statistically significant differences (p > 0.05) were observed between the RFA measurements made by the two magnetic devices. The intra-observer reliability of both devices was excellent, whereas the interobserver reliability of the devices was poor. Conclusion: The results of the RFA measurements of both tested devices overlap. Although both devices show excellent intra-observer reliability, there are variations between the measurements of different examiners.