# Antibacterialarial Agents Used in Modifications of Dental Resin Composites: A Systematic Review
## 4 Discussion
### Modification of RBC Compositions
#### 4.2.2 Other Additives
[51] used commercial barium borosilicate-based glass powders, which are commonly used fillers in dentistry. However, the powders were covalently immobilized with silver sulfadiazime to allow them to provide antimicrobial activity. Modification of the glass powders resulted in strong antimicrobial activity against _Streptococcus mutans_. Composite materials based on bisGMA, with 2% to 10% glass powders with silver sulphadiazine, were shown to exhibit strong and sustained antibacterial efficacy against _Streptococcus mutans_. This modification did not adversely affect the mechanical properties of the prepared composites. Cytotoxicity tests should be performed and consider the overall effect of adding such fillers in terms of material longevity. [PERSON] et al. [52] used antimicrobial modification with 3D zinc oxide (ZnO) microstructures. The use of small amounts of ZnO microparticles reduced the growth of _Streptococcus mutans_ bacteria on the surface of the material used. It was shown that the modification did not adversely affect the compression strength of the composite, nor did it affect the diametral tensile strength. Zinc oxide was also used for another antibacterial modification. Cellulose nanocrystal/zinc oxide (CNC/ZnO) nanohybrids were introduced into the experimental composite. Studies by [PERSON] et al. showed that the use of a 2 wt% CNC/ZnO nanohybrid reduced the number of _Streptococcus mutans_ bacteria by up to 78%. High concentrations of CNC/ZnO nanohybrids led to a reduction in compressive strength, flexural strength, and Vickers microhardness, but not flexural modulus [53]. [PERSON] and others used core-mesoporous shell-structured ZnO@m-SiO\({}_{2}\) to modify composites. It was found that the composite modified with Z\({}_{7}\)S\({}_{63}\) (ZnO@m-SiO\({}_{2}\):silanizedSiO\({}_{2}\) = 7:63 wt./wt., total filler content 70 wt%) showed the best compressive and flexural strength and modulus of elasticity. The experimental composite demonstrated remarkable antibacterial efficacy (>99.9%) [54]. [PERSON] et al. [55] decided to enrich the composite material with potentially antibacterial silanized hydroxyapatite nanofibers loaded with erythromycinomycin (s-HAFs@EM). The resin modified with 15% s-HAFs@EM exhibited the highest flexural strength and elastic modulus. Compared with pure resin, these values increased by 65.43% and 90.7%. The study showed that the resin containing 15-20% of the modifier showed a significant antimicrobial index (against _Streptococcus mutans_) compared to the control. In addition, it showed some remineralization capacity and good in vitro biosafety. The observed ability to remineralize is promising, but it is nevertheless necessary to study the long-lasting stability of the mechanical properties of these experimental materials. Another way to avoid the development of caries is to use hydrated calcium silicate (hCS). [PERSON] et al. [56] discovered that an experimental material containing hCS showed significantly stronger antimicrobial activity compared to the group without hCS filler. The addition of hCS to the studied composite resulted in higher water sorption, solubility, and release of Ca and Si ions. The phenomenon of increased water sorption can have a negative impact on mechanical properties, leading to material degradation; hence, studies on the long-lastingness of the properties in wet conditions are required. After immersion in artificial saliva solution (for 30, 60, and 90 days), it was noted that the composite material with 52.5 wt% hCS filler produced precipitates that consisted largely of Ca and P, which were detected as hydroxyapatite [56]. [PERSON] et al. [57] decided to use strontium-modified phosphate glass (Sr-PBG) as a matrix filler. The filler was incorporated at three concentrations--3, 6, and 9 wt%--into a commercial composite (Filtek Z350 XT, 3M ESPE).