Integrity of Implant Surface Modifications After Insertion

Purpose: The surface integrity associated with implant placement was examined to determine whether the topography of common implant surface modifications is retained after implant insertion. Materials and Methods: Turned (TU), acid-etched (AE), and anodized (AN) experimental implants prepared inhouse were inserted into polyurethane foam blocks using a standard drilling protocol at maximum torque of 37 Ncm. Qualitative analysis of the surfaces of preinserted and postinserted implants was done by scanning electron microscopy (SEM), and quantitative analysis of the implant threads was performed by interferometry. Among the roughness parameters calculated were average height deviation (Sa), peak height above core roughness (Spk), and maximum peak height (Sp). Results: SEM showed that TU implants exhibited similar morphology before and after implant insertion. The AE implants showed reduced peak height associated with flattened areas after insertion. AN implants demonstrated the most extensive damage associated with insertion; the entire porous oxide layer had been removed at the apical region and on the crests of the threads. Surface roughness evaluation was corroborated with the SEM findings. Roughness parameters were similar for TU implants, and reduced Sp and Spk values were observed for the AE implants after insertion. AN implants were more complex to measure quantitatively because of variations in the extent of damage to the oxide layer during insertion. In some cases, the AN layer had been completely removed, exposing the underlying material and clearly decreasing the roughness, and in other cases it remained intact and rough. Polyurethane foam blocks in contact with AN implants demonstrated loose titanium particles of different sizes. Conclusion: This preliminary study demonstrated surface damage after insertion of experimental anodized implants into polyurethane blocks associated with loose titanium particles at the interface. Future in vivo studies should investigate the relevance of such loose particles on the peri-implant bone response. Keywords: dental implants, osteolysis, surface characterization, surface roughness