Direct profilometry of the skin: its reproducibility and variability

Abstract Objective The degree of reproducibility and precision of the mechanical direct profilometry and the intra- and interindividual fluctuations of 7 surface parameters were investigated. Material and methods Negative replicas were sampled from defined areas of the skin of 31 volunteers an evaluated with the profile-tracking device TKC 300 Hommeltester in order to derive data about the inter- and intraindividual fluctuations. To determine the precision of this method 6 roughness parameters and 1 of waviness of each replica were repetitively evaluated. The practicability was tested introducing minimal changes in the experimental set-up. Further, the effect of urea-containing creme on the skins topography was investigated in a double-blind clinical setting on a collective of 11 patients. Results The precision of this method is shown by nearly unchanged topographic parameters. Moreover, our data show smaller intra- than interindividual fluctuations of roughness ( R a ) and waviness ( W t ), being an important demand for clinical investigations. Conclusion In this paper we demonstrate that the parameters of both roughness as well as the recently introduced waviness can be conveniently evaluated with a high degree of precision with the direct profilometry.