Nanometrical evaluation of direct laser implant surface M. Ricci, a * F. Mangano, b T. Tercio, a P. Tonelli, d A. Barone, c M. Raspanti b and U. Covani a The present study was designed to evaluate the characteristics and the topography of a new implant surface. Titanium discs were manufactured using master alloy powder (Ti-6Al-4V) with a particle size of 25–45 mm as the basic material (Leader Implants, Milan, Italy). We acquired images in three different dimensional ranges of decreasing dimensions: 30 (dimensional class A), 10 (dimensional class B), and 5 mm 2 (dimensional class C). For each dimensional range, we collected five (dimensional classes A and B) to ten (dimensional classes C) different images, belonging both to the center and to the edge of the slide Results – In dimensional class A, implant surface showed an average roughness value (R a ) of 0.6 mm, whereas the root mean square roughness (R rms ) value was 0.78 mm. In the dimensional class B, value of R a was 133.4 mm and value of R rms was 161.7 mm. Finally, at a smaller level as in dimensional class C, value of R a was 68.5 mm and R rms was 81.05 mm. Moreover, the peak to peak value was 369.5 mm and the average height value was 187.3 mm Discussion – The surface which results from direct laser fabrication process has an ideal nano-roughness to enhance protein adsorption and to facilitate precursor osteoblast adhesion. In conclusion, direct laser forming surface seems to be a promising technique for forming dental implants from titanium alloys. Copyright © 2012 John Wiley & Sons, Ltd. Keywords: atomic force microscopy; laser; implant Introduction The formation of a direct contact between bone and implant surface is a fundamental parameter for the clinical success of endosseus implants. [1] Already more than 25 years ago, Albrektsson stated that the composition of implant surface has a crucial role in the implant- bone response [2] and this statement has recently been confirmed by researchers. [3,4] The biological response to a given biomaterial introduced into human body is mainly determined by the surface characteristics affecting the interaction between the material itself and the biological environment in which the biomaterial is introduced. [5] In vitro studies have supported the idea that surface roughness may increase osteoblast-cell proliferation, influencing the gene expression. [6] Brett et al. observed that more pronounced effects on gene expression were found when cells were grown on rougher surfaces. [7] Furthermore, there are a large number of in vivo studies which confirm that surface roughness may enhance osteointegration. [8–10] However, literature emphasizes that such studies do not seem to be as straightforward as suggested. They did not confirm the idea that the bone implant contact could be improved by increasing roughness of the implant surface. [11] Surface roughness can be divided in to three levels. Macro level is related to implant geometry with threaded screw and macroporous surface treatments giving the implants a roughness of more than 10 mm. Previous studies indicated that mechanical stability is improved by a high roughness surface. [12,13] Surface features in the range of 1–10 mm are linked to a microtopographic profile. This roughness is important in amplifying the interlocking between mineralized bone and the surface of the implant. [12–14] Finally, surface roughness on the nanometer level plays a crucial role in the adsorption of proteins, adhesion of osteoblastic cells, and as a consequence, in osteointegration. [15] However, it is worth remembering that surface roughness in the nanometer range is difficult to assess. As a consequence, the optimal surface nanotopography for a selective adsorption of proteins leading to a better adhesion of osteoblastic cells is still unknown. Nowadays, research is concentrated on strategies for improving both the short and long term osseointegration and modification of the surface roughness at the nanoscale level. Innovative methods for obtaining different surfaces have been proposed such as several rapid prototyping and direct metal forming techniques. Among these techniques, direct laser metal forming offers great potential benefits in the field of the biomaterials. [16] By means of a high energy-focused laser beam, a localized region of a thin layer of metal powder is directly fused in accordance with a three-dimensional (3D) computer aided design (CAD) model. With this technique, it is possible to build, layer by layer, 3D metallic components such as dental implants directly from a CAD model. [16] At present, dental implants can be obtained from the laser fusion * Correspondence to: Dr. Massimiliano Ricci, Via Variante Aurelia 17, 19038 Sarzana (SP), Italy. E-mail: ricci.massimiliano@yahoo.it a Nanoworld Institute–CIRSDNNOB and Biophysics Division, University of Genova, Italy b Private Practice, Gravedona, Como, Italy c Istituto Stomatologico Tirreno, Versilia General Hospital, Lido di Camaiore (Lucca), Italy d Department of Dentistry, University of Florence, Italy Surf. Interface Anal. (2012) Copyright © 2012 John Wiley & Sons, Ltd. Research article Received: 10 December 2011 Revised: 26 May 2012 Accepted: 29 May 2012 Published online in Wiley Online Library (wileyonlinelibrary.com) DOI 10.1002/sia.5087