Stability Measurements of Craniofacial Implants by Means of Resonance Frequency Analysis: 1-Year Clinical Pilot Study

Purpose: The purpose of this pilot study was to apply resonance frequency analysis (RFA) to measure the clinical stability of craniofacial implants and compare the RFA measurements over a 12-month period. Materials and Methods: Patients with auricular or orbital defects were treated with prostheses retained by two or three implants. After healing periods of 3 months for auricular implants and 6 months for orbital implants, prostheses were fabricated. RFA measurements were performed immediately after implant placement, at abutment connection, and at 6 and 12 months. All stability measurements were repeated three times for each implant, and the mean value was used for analyses. For measurements performed after prosthesis delivery, connecting bars and abutments were removed prior to RFA. The stability of both types of implants was compared at different time intervals. Results: Fifty-four implants were placed in 10 patients with auricular defects (26 implants) and 10 patients with orbital defects (28 implants). All auricular implants survived, and four orbital implants in four different patients failed. For auricular implants, statistically significant differences in stability values were noted between implant placement, abutment connection, and 6 months; there was no significant difference between 6 and 12 months. For orbital implants, no significant differences were found between implant placement and abutment connection, a significant increase was observed at 6 months, and no significant difference was seen between 6 and 12 months. No significant differences were found for auricular versus orbital implants between placement and abutment connection, but auricular implants showed significantly higher stability values than orbital implants at 6 and 12 months. Conclusions: The stability of surviving auricular and orbital implants increased with time according to RFA. Prior to failure, the failed implants showed RFA values that were below the mean. Keywords: craniofacial implant, implant stability, resonance frequency analysis