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Composite cure and shrinkage associated with high intensity curing light.
Adrian U J Yap1, N Y Wong, K S Siow
1Department of Restorative Dentistry, Faculty of Dentistry, National University of Singapore, Republic of Singapore. rsdyapuj@nus.edu.sg
Operative Dentistry
|July 25, 2003
Summary
High-intensity light curing for 10 seconds offers time savings for composite resins, but effectiveness varies by material. Conventional curing for 40 seconds yielded better results for some composites, while others showed increased shrinkage.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Biomaterials Engineering
Background:
- Visible light-cured composite resins are widely used in restorative dentistry.
- Polymerization effectiveness and shrinkage are critical factors influencing restoration longevity.
- Optimizing curing time and light intensity is essential for clinical efficiency and material performance.
Purpose of the Study:
- To compare the effectiveness of cure and post-gel shrinkage of three composite resins using high-intensity (10-second) versus conventional-intensity (40-second) visible light polymerization.
- To determine if high-intensity, short-duration curing is a viable alternative to conventional methods for composite resin polymerization.
- To assess the material-dependent responses to different curing protocols.
Main Methods:
- Three visible light-cured composite resins (In Ten-S, Z100, Tetric Ceram) were polymerized using a high-intensity halogen light (1296 mW/cm2) for 10 seconds and a conventional-intensity light (494 mW/cm2) for 40 seconds.
- Cure effectiveness was evaluated by measuring the hardness gradient between the top and bottom surfaces of 2-mm specimens.
- Linear polymerization shrinkage was measured using a strain-monitoring device.
Main Results:
- The impact of curing method on cure effectiveness and shrinkage was material-dependent.
- Conventional 40-second curing with Spectrum light resulted in significantly better cure for In Ten-S and Tetric Ceram compared to 10-second high-intensity curing with Astralis.
- Conventional 40-second curing with Spectrum light led to significantly greater shrinkage for Z100 compared to 10-second high-intensity curing with Astralis.
Conclusions:
- High-intensity light curing offers substantial time savings, potentially making it a viable method for polymerizing composite resins.
- Material selection is crucial when considering high-intensity, short-duration curing protocols to ensure adequate polymerization and manage shrinkage.
- Further research may be needed to optimize high-intensity curing parameters for diverse composite materials.