Toward optimizing dental implant performance: Surface characterization of Ti and TiZr implant materials

Targeting understanding enhanced osseointegration kinetics, the goal of this study was to characterize the surface morphology and composition of Ti and TiZr dental implant substrates subjected to one of two surface treatments developed by Straumann. These two treatments are typically known as SLA and SLActive, with the latter resulting in more rapid osseointegration.

A range of techniques was applied to characterize four different substrate/surface treatment combinations (Ti_SLA, Ti_SLActive, TiZr_SLA, and TiZr_SLActive). Contact angle measurements established their hydrophilic/hydrophobic nature. Surface morphology was probed with scanning electron microscopy. X-ray diffraction, Raman μ-spectroscopy, and X-ray photoelectron spectroscopy were used to elucidate the composition of the near-surface region.

Consistent with previous work, surface morphology was found to differ only at the nanoscale, with both SLActive substrates displaying nano-protrusions. Spectroscopic data indicate that all substrates exhibit surface films of titanium oxide displaying near TiO₂ stoichiometry. Raman μ-spectroscopy reveals that amorphous TiO₂ is most likely the only phase present on Ti_SLA, whilst rutile-TiO₂ is also evidenced on Ti_SLActive, TiZr_SLA, and TiZr_SLActive. For TiZr alloy substrates, there is no evidence of discrete phases of oxidized Zr. X-ray photoelectron spectra demonstrate that all samples are terminated by adventitious carbon, with it being somewhat thicker (∼1nm) on Ti_SLA and TiZr_SLA.

Given previous in vivo studies, acquired data suggest that both nanoscale protrusions, and a thinner layer of adventitious carbon contribute to the more rapid osseointegration of SLActive dental implants. Composition of the surface oxide layer is apparently less important in determining osseointegration kinetics.