Comparative study of calcium phosphate deposition on nanotubular and sandblasted large grit acid-etched titanium substrates

Titanium and its alloys are widely used in biomedical applications due to their excellent properties such as biocompatibility, good corrosion resistance, low density, and high elastic modulus. However, their bioinert behavior often results in prolonged osseointegration periods. Therefore, surface modification techniques have been investigated to improve the bioactivity of titanium. In this study, the morphological and chemical properties of sandblasted, large grit, acid-etched (SLA), and nanotubular (NT) surfaces were investigated before and after the deposition of calcium phosphate (CaP) compounds by a chemical conversion method. Various techniques were used to characterize these surface modifications applied to titanium, including microhardness tests, atomic force microscopy, water contact angle measurements, scanning electron microscopy, grazing angle X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that the SLA surface was rougher than the NT surface, and the hydrophilic behavior of both samples was enhanced after immersion in NaOH and chemical conversion. The higher concentration of Ca, P, and phosphate functional groups on the NT surface indicates that a greater amount of CaP was deposited on this surface. The CaP-modified NT surface exhibited a favorable surface topography and chemical composition, which may be advantageous for use in titanium dental implants. In addition, in vitro assays showed that the samples prepared here are promising candidates for biomedical use, as they exhibited high cell viability, non-toxicity, and osteogenic properties.