The method includes the following steps: formulation of liquid, non-gelled and stable precursor by solvolysis of Ti(IV) compounds; precursor deposition on endosseous implant surface; thermal treatment to achieve film densification, in the presence of oxygen, of a complex formed by the above mentioned endosseous implant and precursor, to obtain on the implant surface a thin film of nanocrystalline titanium dioxide with good mechanical and chemical stability. The complex above, under a persistent W irradiation modify its surface status conferring a sensible increasing of wettability chemical and biological decontamination.