The effect of limited lateral resolution in the measurement of implant surface roughness: a computer simulation

The surface roughness of dental implants affects the bone response elicited. Surface roughness is generally described by a range of surface texture parameters. The aim of the present study was to use computerized simulation to investigate the extent to which the lateral resolution of an instrument/method limits the accuracy of certain surface roughness parameters. The lateral resolution was defined as the pixel size of a profiling system. A surface roughness was simulated by a trigonometric function with random periodicity and amplitude. The function was divided into an array of pixels simulating the pixels of the profiling system. The mean height value for each pixel was used to calculate the surface roughness parameters. It was found that the accuracy of all the surface roughness parameters investigated decreased with increasing pixel size. This tendency was most pronounced for mean slope and developed length ratio; amounting to about 80% of their true values for a pixel size of 20% of the true mean high-spot spacing. It was concluded that the lateral resolution of an instrument/method severely compromises the precision of surface roughness parameters measured for roughness features with a mean high-spot spacing less than five times the lateral resolution.