Effects of heat treatment on surface properties of different coatings with alkali treatment on titanium for dental implants

Titanium is widely used as dental implant since it is bio-inert and osseointegratable. However, provided that this material cannot induce bone growth from its surface, it is usual to carry out different surface treatments in order to develop bioactive coatings that increase both the initial rate of bone development and the biological anchorage of implant attachment to the host bone. The aim of the alkaline treatment is to form an amorphous gel of sodium titanate, which can be stabilized by means of a subsequent thermal treatment. During this, the hydro gel is dehydrated and thickened to form a layer of stable and partially crystallized sodium titanate. In the present work it was analyzed the effects produced by different thermal treatments after the alkaline one, on surfaces of cp titanium with surface treatment of blasting and MAO (micro-arc oxidation process). For each case the surface was characterized in order to enhance the application condition. The temperature of the thermal treatments was 400, 600 and 800 degrees C, since titanate varies its ratio of amorphous and crystalline phase in this range and therefore its properties. The assessment of results was carried out by means of Rockwell-C adhesion standard test, measurement of the initial contact angle by goniometry, X-ray diffraction and analytic scanning electronic microscopy. Characterized post thermal treatment samples, it was observed that the samples treated to 800 degrees C presented a crystalline superficial structure, bad adherence and did not develop apatite growth on its surface. Nevertheless, they presented sufficiently surface hydrophilic. On the contrary, the samples treated at 400 and 600 degrees C presented superficially a partially crystallized phase, with good adhesion and good hydrophilicity. Through SEM-EDS, the formation of a homogeneous apatite layer was observed on their surfaces.