Reliability of Resonance Frequency Analysis as an Indicator of Implant Micromotion: An In Vitro Study.

Purpose: To assess validity and reliability of resonance frequency analysis (RFA) as an indicator of implant micromotion (MM) in implants of different lengths and thread designs.

Materials And Methods: Two types of implants were studied-An implant with an asymmetrical, self-tapping thread design, varying thread pitch and geometry (Myriad Plus; Equinox Medical Technology, Amersfoort, The Netherlands) and a tapered implant with a proprietary buttress thread design (Tapered Internal; BioHorizon). MM was assessed for 2 implant lengths (Myriad-Plus 3.8 × 13 and 3.8 × 9.5 mm) and 2 designs (Myriad-Plus 3.8 × 9.5 mm and BioHorizon 3.8 × 9 mm). Ten implants of each group were inserted in fresh bovine bone of uniform bone density. Insertion torque (IT), implant stability quotient (ISQ), and MM were measured using protocol described in the literature.

Results: Longer implants showed reduced IT, RFA values, and MM compared with shorter implants (P < 0.01). BioHorizon implants showed similar IT, significantly higher ISQ values (P < 0.01), yet higher MM (P < 0.01).

Conclusion: Implant length and macrodesign affect ISQ, MM, and IT. Clinical measurements (ISQ) and IT have limited value as an indicator of implant MM.