## 1 Introduction  
Fluorine is a light-yellow gas that, due to its high chemical activity, is not freely available in nature. The main sources of fluoride in the daily diet are water, tea, cereal products, leafy vegetables, nuts, fish, and potatoes [1]. The incorporation of fluoride in public health measures, such as water fluoridation and the use of fluoride toothpaste, has significantly reduced the prevalence of dental caries in many parts of the world. Fluoride works by promoting the remineralization of tooth enamel and inhibiting the demineralization process. It also has antibacterial properties that help reduce the levels of harmful oral bacteria [2]. However, excessive fluoride intake during tooth development can lead to dental fluorosis, a condition characterized by discoloration and the mottling of the enamel. Dental fluorosis ranges from mild forms, which present as white spots on the teeth, to severe forms that result in brown stains and surface pitting. While mild fluorosis does not typically affect oral health-related quality of life, severe cases can lead to aesthetic concerns and social discomfort [3]. Fluoride is considered the key component of caries prevention. It limits the impact of cariogenic bacteria by extenuating the production of acids and the deposition of bacterial plaque on tooth surfaces and holding back the metabolic transformation of carbohydrates in bacterial cells. It inhibits demineralization by the constant presence of low concentrations of fluoride ions, enabling the repositioning of mineral compounds lost during repeated acid attacks with the formation of fluorohydroxyapatite crystals that are less susceptible to dissolution. It supports and accelerates remineralization by providing higher concentrations of fluoride ions, which ensure the formation of calcium fluoride (CaF2), which is a reservoir of fluoride ions released during the action of acids on the enamel [4]. By leveraging the therapeutic role of fluoride, manufacturers of materials used in restorative dentistry have introduced a wide range of products that influence the increase in fluoride concentration in the oral cavity. Starting with conventional glass-ionomer cements (CGICs), progressing through compomers and giomers, and ending with composites coated with a fluoride-containing binding component. Glass-ionomer cements used in dentistry for over 30 years have undergone numerous changes and enhancements. CGICs consist of a liquid and a powder containing a fluoro-alumino-silicate glass filler, which serves as a base containing fluoride. The liquid contains acrylic acid or its copolymers with a possible content of aliphatic polycarboxylic acids. There are also water-activated glass-ionomer cements (WAGICs) that have the addition of an acidic polymer in powder. Upon mixing with water, an acid-base reaction occurs, influencing the material's hardening [5; 6; 7]. These cements have the ability to replenish the pool of fluorides from the environment, acting as a fluoride reservoir and ensuring long-term fluoride release [8]. Compomers are another type of restorative material that combines the advantages of composites and glass ionomers [9]. In the latest versions of this product, silicon-calcium-aluminum-fluoride glass particles (42-67% by volume) are embedded in a conventional methacrylate matrix. This material hardens through two types of reactions: polymerization and acid-base reaction [10; 11]. These materials exhibit high aesthetics and fluoride-releasing capabilities, albeit to a lesser extent than CGICs [12]. In turn, hybrid materials derived from glass ionomers and composites are also known as giomers. They contain fluoro-alumino-silicate filler particles that have undergone a prior (partial or complete) reaction with polyacrylic acid, known as pre-reacted glass-ionomer filler (PRG) technology [8; 13]. Giomers demonstrate superiority over compomers in terms of releasing a greater amount of fluoride and absorbing more from the oral cavity environment [14; 15].