Related Experiment Video
Updated: May 1, 2026
Application of Light-cured Dental Adhesive Resin for Mounting Electrodes or Microdialysis Probes in Chronic Experiments
Published on: July 30, 2007
Ultra-fast light-curing resin composite with increased conversion and reduced monomer elution
Luc D Randolph1, William M Palin2, Sabine Bebelman3
1Louvain Drug Research Institute, Université catholique de Louvain, Brussels, Belgium; Institute of Condensed Matter and Nanosciences, Bio- and Soft- Matter, Université catholique de Louvain, Louvain-la-Neuve, Belgium; CRIBIO (Center for Research and Engineering on Biomaterials), Brussels, Belgium.
New photoinitiators like Lucirin-TPO enable faster curing and less monomer elution in dental composites compared to traditional systems. This advancement offers improved clinical applications for dental materials.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Photochemistry
Background:
- Conventional photoactive resin composites often rely on Type 2 photoinitiators like camphorquinone.
- These systems can exhibit limitations in curing speed and monomer elution, particularly at short irradiation times.
- Type 1 photoinitiators offer an alternative with potentially different photoactivation properties.
Purpose of the Study:
- To compare the degree of conversion (DC) and monomer elution of resin composites using a Type 1 photoinitiator (Lucirin-TPO) versus a Type 2 system (camphorquinone/DMAEMA).
- To evaluate the impact of varying curing times and light intensities on these properties.
- To test the hypothesis that Type 1 systems would show reduced DC or increased monomer elution at short curing times.
Main Methods:
- Two experimental resin composites were formulated with either Lucirin-TPO or camphorquinone/DMAEMA.
- Specimens were light-cured using specific irradiation protocols (time and intensity) matched to each initiator's absorption spectrum.
- Degree of conversion (DC) was measured via Raman spectroscopy, radical concentration by electron paramagnetic resonance (EPR), and monomer elution by high-performance liquid chromatography (HPLC).
Main Results:
- The null hypotheses were largely rejected, indicating significant differences between the initiator systems.
- Lucirin-TPO-based composites demonstrated up to 20x faster curing and at least 4x less monomer elution compared to camphorquinone-based composites.
- At 1000mW/cm² and 1s irradiation, Lucirin-TPO yielded a 10% higher DC, attributed to a greater radical yield shown by EPR.
Conclusions:
- Lucirin-TPO is highly efficient in absorbing and converting photon energy, especially with appropriately matched curing light.
- Optimal performance of Lucirin-TPO requires a minimum light intensity of 1000mW/cm² and 1s exposure for significantly improved DC and minimal elution.
- Lucirin-TPO represents a promising alternative to camphorquinone in dental applications, offering enhanced efficiency and reduced monomer release.
