Retraction:Biomechanical and histological evaluation of four different titanium implant surface modifications: An experimental study in the rabbit tibia

Objectives: This study presents a biomechanical comparison of bone response to commercially pure titanium screws with four different types of surface topographies placed in the tibial metaphysis of 30 rabbits. Materials and methods: One hundred twenty implants were tested double-blinded: (a) blasted, acid-etched, and discrete crystal deposition (DCD), (b) blasted, (c) acid-etched, and (d) blasted and acid-etch. Resonance frequency analysis (RFA/ISQ), reverse torque values (RTV), and bone-to-implant contact (BIC) were measured at the time of implant insertion (day 0), 15, 28, and 56 days of healing. Results: All groups tested demonstrated increased RFA/ISQ and RTV results over the time course. At 15 days, the blasted, acid-etched, and DCD group demonstrated a non-significant trend toward higher values when compared to the blasted and etched group (33.0 ± 16 vs. 26.3 ± 12 Ncm, p =.16). At 56 days, the groups utilizing blasting to create additional surface roughness (Sa > 1 micron) showed a statistical significant difference in RTQ versus the non-blasted group (38.5 ± 14 vs. 29.5 ± 9 Ncm, p =.03). Conclusions: Within the limitations of this study, only the increase in surface roughness (Ra > 1) at 56 days demonstrated statistically significant effects on RTQ. Other additional surface features, such as sub-micron scale DCD, demonstrated improved healing trends but without significance for clinical applications.