## 5 Conclusions  
Based on the obtained results and within the study's limitations, the following conclusions and comments can be drawn:  
* The process of aging results in a reduction in materials' durability by an average of 30% compared to the control values. * There is a strong correlation between flexural strength and the fatigue flexural limit after aging. * No significant relationships were identified between the material's flexural strength or fatigue flexural limit and its fracture toughness after aging. * A standard for fracture toughness testing for dental composites should be developed. * The minimum value of FS after aging, postulated by the authors, should exceed 32-48 MPa. Figure 4: Percentage changes in the flexural strength (FS), diametral tensile strength (DTS), Vickers hardness (HV), fracture toughness (FT), and flexural fatigue limit (FFL) values of the tested materials after the selected aging protocols. Key: 0—no change; positive value—the selected property was higher than the control value after applying the protocol. The aging conditions used were as follows: 7 d NaOH—0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C; thermocycling + NaOH—water, 7500 thermocycles, 5/55 \({}^{\circ}\)C and 0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C; 5 d water + NaOH—water, 5 days, 55 \({}^{\circ}\)C and 0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C.  
* A comprehensive examination of commercially available materials is recommended to enhance the appropriate assessment methods for new composite materials, allowing for the determination of their stability during use. * To minimize the costs and time of material characterization, testing the flexural strength and fracture toughness after aging should be prioritized. Conceptualization, A.S.-W. and J.S. ; data curation, A.S.-W.; formal analysis, A.S.-W. and M.F. ; funding acquisition, A.S.-W. and J.S. ; investigation, A.S.-W. and K.R.-S; methodology, A.S.-W., K.R.-S. and K.B. ; supervision, J.S. ; visualization, A.S.-W. and M.F. ; writing--original draft, A.S.-W., M.F and K.R.-S.; writing--review and editing, A.S.-W., J.S. and K.B. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Science Centre, Poland [grant number: UMO--2020/37/N/ST5/00191, 2021]. Not applicable. Data Availability Statement: Data are available in a publicly accessible repository, Zenodo, at [[https://doi.org/10.5281/zenodo.13165877](https://doi.org/10.5281/zenodo.13165877)]([https://doi.org/10.5281/zenodo.13165877](https://doi.org/10.5281/zenodo.13165877)) (accessed on 8 August 2022). The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. Figure 10: Box-and-whisker plot of three-point bending flexural strength (FS) of Flow-Art after selected aging protocols (control—water, 24 h, 37 \({}^{\circ}\)C; 7 d NaOH—0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C; thermocycling + NaOH—water, 7500 thermocycles, 5/55 \({}^{\circ}\)C and 0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C; 5 d water + NaOH—water, 5 days, 55 \({}^{\circ}\)C and 0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C). Statistically significant differences were detected between the following: (a, b, c) control vs. (a) 7 d NaOH (\(p\) = 0.000001), (b) thermocycling + NaOH (\(p\) = 0.000008), and (c) 5 d water + NaOH (\(p\) = 0.000000). Figure A4: Box-and-whisker plot of the diametral tensile strength (DTS) of Resin F after selected aging protocols (control—water, 24 h, 37 \({}^{\circ}\)C; 7 d NaOH—0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C; thermocycling + NaOH—water, 7500 thermocycles, 5/55 \({}^{\circ}\)C and 0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C; 5 d water + NaOH—water, 5 days, 55 \({}^{\circ}\)C and 0.1 M NaOH, 7 days, 60 \({}^{\circ}\)C). Statistically significant differences were detected between the following groups: (a) control group vs. (a) 5 d water + NaOH group (\(p\) = 0.00714).