An optical three-dimensional technique for topographical descriptions of surgical implants.

The purpose of this study was to develop a noncontacting optical method for the topographical description of surfaces. The method is suitable for all types of surgical implants, including threaded ones. The TopScan 3D system employs a scanning spot and a stationary object at a relatively large working distance to enable proper object alignment, and the depth discrimination property of confocal laser scanning microscopy forms the basis of its surface profiling ability. Scanning is achieved by precision movement of the microscope objective along three orthogonal axes (X, Y, Z). Three-dimensional surface topographical maps are produced by performing a series of parallel XZ scans in Y steps. Eighty seven screw-shaped titanium implants were divided into five groups each with a different surface roughness. The five groups were obtained by varying the size of the blasting particles and by leaving one group 'as-machined'. By using the TopScan 3D approach, we were able to calculate different kinds of surface roughness parameters and to produce visual images from the groups. As expected, the surfaces blasted with large particles showed higher values for the surface parameters than those blasted with smaller particles; the latter had higher values than the 'as-machined' screws.