Hydrophobically Modified Isosorbide Dimethacrylates as a Bisphenol-A (BPA)-Free Dental Filling Material

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials

Background:

• Dental restorative resins often contain Bisphenol A (BisGMA), raising health concerns.
• There is a need for bio-based, BPA-free alternatives with comparable or superior performance.

Purpose of the Study:

• To synthesize and characterize novel bio-based hydrophobically modified isosorbide dimethacrylates (ISBGBMA) with varying aromatic spacers.
• To evaluate these monomers as potential dental restorative resins, comparing their properties to reference materials.

Main Methods:

• Synthesis of ISBGBMA monomers with para-, meta-, and ortho-benzoate aromatic spacers.
• Photopolymerization of ISBGBMA monomers with triethylene glycol dimethacrylate (TEGDMA).
• Evaluation of polymer properties: monomer conversion, polymerization shrinkage, water sorption, glass transition temperature (Tg), and flexural strength.

Main Results:

• Poly(ISBGBMA/TEGDMA) exhibited lower water sorption (39-44 µg/mm³) than Poly(ISDGMA/TEGDMA) (73 µg/mm³) but higher than Poly(BisGMA/TEGDMA) (26 µg/mm³).
• Flexural strength of Poly(ISBGBMA/TEGDMA) (37-45 MPa) was superior to Poly(ISDGMA/TEGDMA) (10 MPa) but lower than Poly(BisGMA/TEGDMA) (53 MPa) after DPBS immersion.
• Poly(ISB2GBMA/TEGDMA) showed the highest Tg (85 °C) and its monomer mixture had the lowest viscosity (0.62 Pa·s).

Conclusions:

• The ortho-substituted ISBGBMA monomer demonstrates potential as a bio-based, BPA-free replacement for BisGMA in dental resins.
• Further research focusing on the ortho ISBGBMA monomer is warranted for developing advanced dental restorative materials.