## 1 Introduction  
Titanium is a material devoid of toxicity and is stable and easy to obtain. Its good physical properties have led to its widespread use in oral implantology.  
To improve its clinical characteristics, there have been attempts to increase the bioactivity of titanium implants [1; 2; 3]. The focus was on improving osseointegration, which is defined as the direct and functional connection between living, structured bone and the surface of an implant under load.  
Among other factors, the physicochemical properties of the implant surface, its topography, and chemical composition have been the focus for improving biocompatibility [4]. Under optimal conditions, this improvement implies an increase in the absorption of ions and molecules, thus stimulating cellular attraction, proliferation, and expansion. The result is a higher degree of contact between the bone and the implant (BIC).  
One method to establish surface improvement is through its wettability, which is based on the angle of contact between a droplet of water and the surface of the material being checked (Figure 1).  
Arbitrary degrees of wettability have been established, depending on the angle of contact, and the parameter is classified into four categories: superhydrophobic, hydrophobic, hydrophilic, and superhydrophobic (Figure 2).  
There are reports that titanium surfaces become contaminated by atmospheric carbon compounds being deposited on their surface, causing them to become progressively more hydrophobic. This process is called biological ageing and has been widely discussed in various works.  
Over time, the percentage of carbon deposited on titanium increases from 14% to 63% with important clinical consequences.  
Aged titanium surfaces exhibit 50% less absorption of amino acids, proteins, and osteoblast adhesion compared with newly manufactured titanium surfaces. Such alterations are considered unavoidable and depend on the storage time, having been detected as early as four weeks after manufacture.  
The physicochemical effect produced by the application of ultraviolet light to the titanium surface is called photofunctionalization, with biological effects. Photofunctionalization is capable of creating a superhydrophobic surface without altering or modifying any other characteristic of the titanium surface. Therefore, it has been proposed as a simple and effective method to reverse the effects of titanium ageing, which can in turn lead to a faster and more complete establishment of bone-titanium integration. Some authors have called this phenomenon superosseointegration.  
Figure 1: The wettability of a surface depends on the surface energy of the solid, the surface tension of the liquid, and the gaseous phase. Wettability can be established by measuring the contact angle between the liquid and the solid.  
Figure 2: Classification of wettability as a function of contact angle. From superhydrophobic to superhydrophobic.  
The purpose of our study was to determine the effect of two UV-C light sources with a wavelength of 254 nm and an energy of 1400 \(\upmu\)W/cm\({}^{3}\) to obtain a hydrophilic surface, comparing two UV-C sources with different powers (6 and 85 W) and a control group.