Overcoming the Viscosity-Strength Trade-Off in 3D-Printable Dental Resins by Hydrogen Bond Engineering

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Vat photopolymerization 3D printing of dental resins faces a trade-off between low viscosity for printability and high mechanical strength for functionality.
• Existing dental resins often compromise on either printability or mechanical properties.

Purpose of the Study:

• To engineer dental resins that overcome the viscosity-strength trade-off for 3D printing.
• To develop a hydrogen-bond engineering strategy to enhance both printability and mechanical performance.

Main Methods:

• Blended dental oligomers (Bis-GMA, UDMA, Bis-EMA) with diluents of varying hydrogen-bonding ability.
• Utilized Fourier transform infrared (FTIR) spectroscopy and rheometry to assess hydrogen bonding and viscosity.
• Evaluated mechanical properties via three-point bending tests and assessed 3D printing performance and accuracy.

Main Results:

• Confirmed strong hydrogen bonding between methacrylic acid (MAA) and matrix oligomers using FTIR and rheology.
• Achieved a viscosity of 307 mPa·s with an optimized formulation (n(MAA):n(UDMA) = 2:1), significantly lower than neat UDMA (9689 mPa·s).
• The optimized formulation exhibited high flexural strength (178 MPa for 3D-printed) and elastic modulus (4.0 GPa for 3D-printed).

Conclusions:

• Hydrogen bond engineering effectively decouples viscosity from mechanical strength in dental resins.
• This strategy enables the fabrication of low-viscosity, high-strength materials suitable for 3D printing.
• The developed platform offers a scalable solution for photocurable additive manufacturing in dentistry and beyond.