Plant-derived multimethacrylate dendritic monomers: Synthesis and applications in dental restorative resins

Regarding the global increase in dental caries, the development of high-quality resin-based materials is essential. However, it is still a challenge to alleviate the polymerization shrinkage of methacrylate monomers. Herein, we constructed the first- and second-generation betulin-based multimethacrylate dendritic monomers (D₁, D₂, and D₃) via the esterification reaction, which were differed primarily in the number and position of the terminal methacrylate groups. These photo-polymerizable dendritic monomers were introduced as the partial (10 wt%) and total (50 wt%) replacements of bisphenol A glycidyl dimethacrylate (Bis-GMA) in dental restorative resins. Notably, the D₁4B5T resin, composed of 10 wt% D₁, exhibited a significantly lower shrinkage (8.02 ± 0.28 %; 17 % reduction) and improved flexural strength and modulus (87.4 ± 0.8 MPa, 1.9 ± 0.1 GPa) than the commercial resin (9.66 ± 0.29 %; 82.1 ± 0.5 MPa; 1.6 ± 0.1 GPa), due to its well-balanced crosslink density and structure properties. Molecular dynamics simulation of these two resins provided mechanistic insights to how the monomer structure affecting the resin shrinkage. The optimal D₁4B5T resin also possessed better fluidity, cell viability, and acceptable polymerization conversion compared to the commercial control. This study provides new insights into the synthesis of plant-derived polymerizable dendrimers and the creation of high-performance dental resins, endowing them promising for biomedical fields such as teeth restorations.