CHARACTERIZING 3-DIMENSIONAL TOPOGRAPHY OF ENGINEERING AND BIOMATERIAL SURFACES BY CONFOCAL LASER-SCANNING AND STYLUS TECHNIQUES

Three-dimensional measurements of surface topography were performed us ing a confocal laser scanner and a contact stylus instrument. Three su rfaces known to be difficult to evaluate were chosen to be measured on the same area with the two instruments. The measurements from the opt ical and the contact stylus profilometer were compared with each other and with measurements obtained from high-resolution atomic force micr oscopy, which served as a reference instrument. Six implants manufactu red from commonly used biomaterials were also measured on the same par t of the implant, but not on the same area, with the optical and the c ontact profilometer in order to stimulate the measurements that would be performed wizen different laboratories measure similarly treated su rfaces. The numerical and visual differences achieved when measuring t he same area with the two instruments investigated were compared. In g eneral, we found an underestimation of the surface features with the c ontact stylus measurement and an overestimation with the confocal scan ner The stylus readings are mainly influenced by the radius of the sty lus tip, the pressure of the stylus tip on the surface, and the hardne ss of the material the optical profilometer has a tendency for creatin g spikes when surfaces with deep slopes are measured. For relatively s oft metallic biomaterials, we found that using the optical instrument is the most appropriate method for surface roughness characterization, particularly when screw-shaped implants are analysed, whereas the sty lus is preferred when larger areas with substantial slopes within the surface structure are to be evaluated. Copy right (C) 1996 Elsevier Sc ience Ltd for IPEMB.