*2.1.1 Machined surfaces (smooth)*

Machined implants with an untreated surface are considered to have a smooth surface. Machined implants with an untreated surface are considered to have a smooth surface. However, they have small grooves that allow the bone mineralization process towards the implant, but they do not have an osteoinductive surface. This type of surface is considered anisotropic, which is responsible for promoting the cell adhesion process and the production of the protein matrix. The machined implant has a surface roughness between 0.5 μm and 1 μm. This smooth surface is formed a surficial microgroove, resulting from the machining process, produced by the passage of the cutting tool. This type of surface does not receive chemical or mechanical treatment, presenting only the micromorphology of the machining process [9]. **Figure 3** shows representative images of a smooth surface at different magnifications.
