Introduction: In the case of a completely edentulous jaw, one of the most common tooth replacements is a total denture, which is made of acrylic resin and prefabricated teeth. It restores the patient's appearance, smile and the ability to perform physiological functions such as chewing, swallowing and speech, while also having a beneficial effect on the patient's psycho-physical well-being. The advantage of using advanced denture materials is reflected in better mechanical properties (strength, durability, corrosion resistance, biocompatibility). A number of studies have shown the effects and progress made using nanocomposites that have favourably influenced the mechanical and physiological properties of the material, including TiO2. Purpose: The aim of this thesis is to investigate how the addition of TiO2 nanoparticles to PMMA changes some mechanical properties (contact angle, zeta potential, roughness, colour, elastic properties) and the adhesion of Streptococcus mutans. Methods: The introductory theoretical part is written after a literature review of mainly foreign peer-reviewed articles from databases such as PubMed, GoogleScholar and Web of Science. In the practical part, under the supervision of the mentor, we made acrylate plates with different TiO2 nanoparticle contents (0%, 1%, 5%), which were then measured for the limiting angle at the Faculty of Health Sciences (University of Ljubljana), for the colour at the private dental laboratory Franc Rojko, and for the roughness, zeta potential and bacterial adhesion at the Jožef Stefan Institute. We also measured the elasticity of the material at the Slovenian national building and civil engineering institute. Results: The test subjects were prepared in the dental laboratory of Franc Rojko. Measurements and tests were carried out at the Faculty of Health Sciences, University of Ljubljana, the Jožef Stefan Institute, the Building Research Institute of Slovenia and the Faculty of Biotechnology, University of Ljubljana. The maximum roughness, zeta potential and contact angle were measured on PMMA + 1% TiO2. Pure PMMA and PMMA + 1 % TiO2 are hydrophobic, while the 5 %, 10 % and 20 % TiO2 test specimens have a hydrophilic surface. The addition of TiO2 to PMMA reduced the percentage of attached S. mutans bacteria on the material compared to pure PMMA. The uniaxial tensile strength decreased with increasing TiO2 concentration. The addition of TiO2 to PMMA resulted in a brighter colour, less reddish and bluish tones. Discussion and conclusion: Based on the data obtained, it can be summarised that PMMA modified with TiO2 nanoparticles is not suitable for the fabrication of prosthetic restorations as it does not meet the colour requirements. Roughness, zeta potential and hydrophobicity have a significant effect on bacterial attachment. The main clinical drawback of pure PMMA is its poor antibacterial activity. For the use of TiO2 in the fabrication of prosthetic restorations, a suitable solution for colour matching would need to be found.
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