Evaluation of bio-based monomers from isosorbide used in the formulation of dental composite resins

The objective of this study was to synthesize two bio-based monomers from isosorbide, the bis(allylcarbonate) isosorbide (IBAC) and the bis(methacrylate) isosorbide (IBM), and to evaluate its effect as Bis-GMA diluents in the formulation of photopolymerizable dental composite resins. The chemical structure of both bio-based monomers was determinate by means H-1 NMR, C-13 NMR and FTIR spectroscopies. Experimental composites comprising Bis-GMA/IBAC or Bis-GMA/IBM were formulated using 65 %wt of silanized inorganic filler. Experimental materials were compared with a control composite formulated with Bis-GMA/TEGDMA. Double bond conversion, polymerization kinetics, volumetric shrinkage, water sorption, solubility, and flexural properties were investigated. The data were analyzed by one-way ANOVA and Tukey test (alpha = 0.05). Flexural strength of the experimental materials was similar to the control (p = 0.733). Bis-GMA/IBM achieved the highest values of elastic modulus (p = 0.135). Bis-GMA/IBAC composite achieved the highest values of degree of conversion, while the values of Bis-GMA/IBM composite were similar to the control (p > 0.05). There were no differences in the polymerization shrinkage of the composites, however, the polymerization stress of the experimental materials was lower (p < 0.05). Finally, the cell viability test showed that the experimental resins formulated with the bio-based monomers were not cytotoxic. Due to its characteristics, IBAC and IBM monomers are potentially useful for the formulation of composite materials with applications in dentistry.