Resonance frequency measurements in vivo and related surface properties of magnesium‐incorporated, micropatterned and magnesium‐incorporated TiUnite®, Osseotite®, SLA® and TiOblast® implants

Abstract

To investigate implant stability using resonance frequency measurements of topographically changed and/or surface chemistry-modified implants in rabbit bone. Six groups of microstructured, screw-shaped titanium implants: two oxidized, cation-incorporated experimental implants [Mg implants and MgMp implants with micropatterned thread flanges (80-150 microm wide and 60-70 microm deep)] and four commercially available clinical implants (TiUnite((R)), Osseotite((R)), SLA((R)), and TiOblast((R))) were installed in 10 rabbit tibia for 6 weeks. The surface properties of the implants were characterized in detail using several analytical techniques. Implant stability was measured using a resonance frequency analyzer (Osstell(TM)). Surface characterization of the implants revealed microstructured, moderately rough implant surfaces varying 0.7-1.4 mum in S(a) (mean height deviation), but with clear differences in surface chemistry. After 6 weeks, all implants showed statistically significantly higher increases in implant stability. When compared with one another, MgMp implants showed the most significant mean implant stability quotient (ISQ) value relative to the others (P<or=0.016). In terms of increment (DeltaISQ) in implant stability, MgMp implants showed a significantly greater value as compared with Osseotite((R)) (P<or=0.005), TiOblast((R)) (P<or=0.005), TiUnite((R)) (P<or=0.005), SLA((R)) (P<or=0.007), and Mg implants (P<or=0.012). In addition, transducer direction dependence of resonance frequency analysis (RFA) measurements was observed such that the differences in the mean ISQ values between longitudinal and perpendicular measurements were significant at implant placement (P<or=0.004) and after 6 weeks (P<or=0). The present study found that implant surface properties influence RFA measurements of implant stability. Surface chemistry-modified titanium implants showed higher mean ISQ values than did topographically changed implants. In particular, cation (magnesium)-incorporated micropatterns in MgMp implants may play a primary role in DeltaISQ.