Factors Affecting Resonance Frequency of One Stage Dental Implants

Purpose: Resonance frequency (RF) is a noninvasive method to evaluate implant stability. It has been reported that the distance of the transducer from bone influences RF. The purpose of this preliminary study was to determine whether RF analysis is affected by the orientation of the RF instrument handpiece against the transducer.

Methods: Ten patients (8 males, 2 females; aged 26 to 74 years) scheduled to have a single, one-stage implant were included. Exclusion criteria were smokers and contraindication for one-stage implant placement. Immediately following implant placement, RF readings were obtained from 6 different orientations around the dental implant with Osstell Mentor^TM by two calibrated examiners. Readings were repeated at post-operative appointments. Observed variations in readings between orientations and the two examiners were analyzed by using repeated measures ANOVA test (P<0.05).

Results: Inter- and intra-examiner differences in RF measurements were observed at surgery and during healing period and they were in the range of 1 to 5 ISQ unit. RF measurement differences between orientations were higher immediately after implant placement (7.3+/-6 ISQ) compared to more stable repeats (4.4+/-4 ISQ) 3 or 6 weeks, postoperatively.

Conclusion: Within the limits of this study, it appears that the handpiece orientation against the transducer affects RF measurements, especially at surgery. However, the variation observed between repeats is minimal. (Supported by CTOC Program, NIDCR Grant T32 DE14320 and the OSU Section of Periodontology)