Assessing the roughness of titanium dental implants

OBJECTIVES. The aim of this study is to enhance the current understanding of the physical meaning of some roughness parameters, and to promote their implementation as routine methodology for assessing the state of surfaces. MATERIALS AND METHODS. It is well known that the parameter "average roughness" Ra is often used to characterize the roughness of dental implants, especially in the commercial field, but it does not define the surface state; there are, however, various other roughness parameters defining the device topography in a univocal way. The physical meaning of some roughness parameters, like Sa, Sq, Sku and Ssk has thus been considered. The effect of sandblasting duration (1, 2, 4 and 8 min) and hydrofluoric acid etching, as well as their combined or synergic effect on the surface topography of commercially pure titanium (Ti CP) grade 2 and grade 4, have been investigated in order to highlight the use of those parameters. The experimental results statistical significance has been validated using analysis of variance. RESULTS AND CONCLUSIONS. We propose to use the roughness parameters Sa, Sq, Sku and Ssk to evaluate dental implant topography. Their implementation shows that: (i) it is possible to distinguish between surfaces that have undergone different treatments; (ii) the experimental results obtained show that sandblasting, performed on Ti CP grade 2 and Ti CP grade 4, under the same experimental conditions, induces completely different topographic features. To compare results obtained by different authors, the above parameters should be used in describing the implants surface state.