Application of the novel BMEP monomer in experimental self-adhesive dental composite physicochemical and mechanical...

Adhesive dentistry has revolutionized with the proposal of self-adhesive composites (SACs), which aim to simplify restorative procedures by omitting the need for separate dental bonding agents' applications. Even though the limitations of these composites, including their questionable bond strength and long-term durability, remain our issues. Therefore, this in vitro study suggests a novel BMEP monomer designed to enhance the dental composite's physicochemical and mechanical properties. The objective of this study was to investigate the effectiveness of different concentrations of the BMEP monomer in improving the overall performance of self-adhesive dental composites. Experimental SACs were synthesized by mixing TEGDMA, UDMA, photo-initiator, fillers, 0%, 7%, 10%, and 20% BMEP monomer, as well as 5% 10-MDP monomer (control group). Thereafter, the flexural strength and elongation at break of five composite bars were investigated by the Santam Universal Testing Machine (UTM, Santam, Iran). The Vickers test evaluated the microhardness (three composite disks). The curing degree (five study groups) was assessed by the Fourier-transform infrared spectroscopy (FTIR), and the water sorption and solubility tests (five standard disks) were performed on samples according to ISO 4049 standards. Data were analyzed using parametric tests for datasets with > 5 samples and non-parametric tests for smaller groups (α = 0.05). The 7% BMEP group demonstrated the best overall performance, combining high microhardness [median:28 HV (range: 24-29 HV)], flexural strength (81.2 ± 10.4 MPa), low water solubility (3.3 ± 0.27 µg/mm³), low water sorption (42.9 ± 2.42 µg/mm³), acceptable elongation at break (0.57 ± 0.17 mm), and a good degree of cure [median: 53.3% (range: 52.1-57.4%)]. In contrast, the 10-MDP control group exhibited significantly lower values in degree of cure [median: 42.9% (range: 41.6-44.5%)], microhardness [median: 20 HV (range: 19-22 HV)], and flexural strength (79.6 ± 12.4 MPa) (p < 0.05). Differences between some BMEP groups showed a trend but did not reach statistical significance. In conclusion, the composite containing 7% BMEP monomer demonstrated a favorable balance of properties and is recommended for further study.