Ester-free thiol-ene dental restoratives--Part B: Composite development

Area of Science:

• Materials Science
• Dental Materials
• Polymer Chemistry

Background:

• Traditional dental composites often rely on ester-containing monomers, which are susceptible to hydrolysis, leading to degradation and reduced service life.
• Developing hydrolytically stable dental composite matrices is crucial for improving the longevity and performance of dental restorations.

Purpose of the Study:

• To evaluate the performance of novel ester-free thiol-ene dental composites.
• To compare the properties of these composites against conventional dimethacrylate-based materials.
• To highlight the advantages and disadvantages of using a stable thiol-ene matrix in glass-filled dental composites.

Main Methods:

• Preparation of glass-filled composite samples using selected ester-free thiol-ene formulations.
• Photopolymerization using visible light and assessment of shrinkage stress and degree of conversion (FT-IR).
• Mechanical testing (flexural strength, elastic modulus) and dynamic mechanical analysis after curing and aging in water.

Main Results:

• Thiol-ene composites achieved comparable or higher conversions than dimethacrylate controls.
• Lower shrinkage stress was observed in thiol-ene composites at similar conversion levels.
• While initial elastic moduli were lower, flexural strengths were comparable. Importantly, mechanical properties remained unaffected by water aging, unlike controls.

Conclusions:

• Ester-free thiol-ene dental composites demonstrate excellent hydrolytic stability and robust mechanical properties.
• The use of non-degradable, step-growth networks offers a pathway to structurally uniform, tough dental materials with extended service times.
• These findings suggest thiol-ene composites are a viable alternative for durable dental restorations.