# Evaluation of the Impact of Various Functional Fillers on Key Properties of Dental Composites
## 1 Introduction
demonstrated that incorporating SiO\({}_{2}\) particles into composite resin led to a substantial enhancement in flexural strength [10]. Similar findings were reported by [PERSON] and [PERSON], who researched the incorporation of ZrO\({}_{2}\) particles [23]. Recently, there has also been a growing use of antibacterial fillers [24, 25, 26, 27, 28], which play a crucial role inaddressing the issue of secondary caries [24; 29; 30]. Additionally, calcium phosphate fillers (i.e., hydroxyapatite (HAp)) are gaining attention due to their excellent biocompatibility and bioactivity [31; 32]. Worryingly, some studies report unsatisfactory mechanical properties when these materials are used as fillers in dental composites [11; 33]. This highlights the need for further research to enhance their performance. An effort to address this issue was made by [PERSON] et al. [34], who utilized fluorohydroxyapatite (FHA) nanotubes in their experiments. Their findings demonstrated improved mechanical properties in composites based on Bis-GMA resin [34]. Additionally, our findings suggest that the incorporation of various fillers, including remineralizing and antibacterial agents, holds significant potential for enhancing composite properties. A synergistic effect can often be achieved by combining different fillers. For instance, the addition of nanosilver enhances the antibacterial properties of the composite, potentially addressing the issue of secondary caries formation. Without any doubt, achieving strong adhesion between the composite and tooth tissues remains a critical aspect of development. While studies such as those by [PERSON] [34] have explored the use of nanotubes, our research focused on the use of nanoparticles as fillers. Notably, no prior research has simultaneously employed three distinct filler particles hydroxyapatite, calcium fluoride, and nanosilver to modify the same composite. In recent years, most researchers have focused on the modification of composite materials using hydroxyapatite (HAp) fillers. The introduction of this type of filler is intended to achieve much better aesthetic results. Commercial dental composites discolor after some time. This is caused by aggressive conditions in the oral cavity and the intake of coloring liquids such as coffee, tea, and red wine. However, achieving better aesthetic results may involve the deterioration of mechanical properties. Therefore, attempts have been made to improve mechanical properties while maintaining aesthetics. For this purpose, additional fillers, such as fluoride and nanosilver, have been introduced. Additionally, the introduction of nanosilver was intended to reduce bacterial adhesion. So far, scientists have not introduced the three different functional fillers hydroxyapatite, fluorine, and nanosilver into the flow composite based on bisphenol A-glycidyl dimethacrylate (Bis  
Figure 1: Types of functional fillers. GMA). Our work is the only one that focuses on the introduction of different fillers such as hydroxyapatite (HAp), fluoride, and nanosilver. Most of the current research work has been conducted on other types of composites, such as (UDMA), TEGDMA, and glass ionomers, and using only one or two functional fillers. Previous research work has focused on the use of nano-sized hydroxyapatite. In our work, hydroxyapatite was used in the macroscale. We are the only ones who have performed impact strength tests for dental composites. The aim of this study was to assess the mechanical properties of experimental flow composites incorporating remineralizing and bactericidal fillers (hydroxapatite, calcium fluoride, and nanosilver). The evaluated properties included wear resistance, dynamic properties (impact strength), hardness, and static strength (compressive and bending strength). The null hypothesis posited that the incorporation of hydroxyapatite, calcium fluoride, and nanosilver as fillers in dental composites does not affect their mechanical properties.