Use of NIR light and upconversion phosphors in light-curable polymers
Alexander Stepuk1, Dirk Mohn, Robert N Grass
1Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland.
Summary
This study introduces upconversion filler particles for faster, deeper curing of dental resins using near-infrared (NIR) light. This method improves polymerization and offers an alternative to traditional blue light curing in dentistry.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Dental Materials
Background:
- Light-curable polymers are essential in dental restorative procedures.
- Current blue light curing is limited by poor light penetration, necessitating layered application.
- This restricts treatment to visible areas and complicates deep defect restoration.
Purpose of the Study:
- To investigate the use of upconversion filler particles for enhanced polymerization of dental resins.
- To enable efficient curing using deep-penetrating near-infrared (NIR) light.
- To overcome the limitations of blue light penetration in dental applications.
Main Methods:
- Incorporation of upconversion filler particles into dental resin composites.
- Photo-activation using near-infrared (NIR) light (800-1200 nm).
- Absorption of NIR light by fillers and conversion to 450 nm blue light for polymerization.
Main Results:
- Achieved uniform polymer hardening via on-demand blue light generation.
- Curing time for 5mm composite samples was reduced by 50% (30s vs 60s) compared to blue light.
- Demonstrated a monomer conversion degree exceeding 40%.
- Confirmed enhanced NIR light transmission through dentin and enamel.
Conclusions:
- Upconversion filler particles facilitate faster curing and higher polymerization degrees.
- This approach offers an alternative to conventional blue light curing for dental resins.
- Improved NIR light transmission may enhance the sealing of deep and complex caries lesions.
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