Titanium (Ti) is a biocompatible material used as a base in the production of dental implants, due to its excellent mechanical properties. However, the alteration of the chemical composition of its surface over time can affect the main biological processes. Ultraviolet (UV) light irradiation, known as "UV photofunctionalization", based on mercury (Hg) vapor lamps, has shown promising results in reducing implant failure rates and improving their biological properties. However, considering the current restrictions and limitations of the use of Hg, it seems necessary to design a photofunctionalization system with alternative light sources, which proves to be effective in improving osseointegration processes and implant survival. The objectives of this doctoral thesis were: to design and develop a UVC photofunctionalization device based on LEDs as light sources; to analyze its effectiveness in the reduction of bacterial biofilms; to evaluate the stimulation of the biological behavior of soft and hard tissue cells. All this is aimed at the safe and effective use of this implant surface treatment technology in clinical practice.

The designed UVC LED photofunctionalization device proved to be effective in decontaminating carbon compounds from the surface of irradiated Ti dental implants, reversing the Ti ageing process, regardless of the type of surface used. Likewise, after 24 h of UVC LED irradiation, the photofunctionalized implants showed an antibiofilm effect after 1 h of bacterial biofilm formation (p < 0.001) and maintained over time up to 6 h (p < 0.01). Furthermore, an improvement in the viability and proliferation of fibroblasts and osteoblasts was observed (p < 0.001), with an increase in osteoblastic differentiation (p < 0.05) and a more elongated cell expansion of both cell lineages. Secretion of interleukins IL-1ß (p < 0.001) and IL-6 (p < 0.05) and proteins such as osteocalcin (p < 0.001) were also upregulated after UVC LED photofunctionalization.