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Immediate polymerization shrinkage in light cured restorative resins
Vanesa I Rodríguez1, Pablo F Abate, Ricardo L Macchi
1Department of Dental Materials, School of Dentistry, University of Buenos Aires, Argentina. vanesaines@hotmail.com
Acta Odontologica Latinoamericana : AOL
|November 24, 2006
Summary
Lowering light activation energy significantly reduces polymerization shrinkage in dental restorative resins. This effect varies based on material composition, highlighting the importance of optimized light curing for dental composites.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Restorative Dentistry
Background:
- Polymerization shrinkage is a critical factor influencing the longevity and performance of dental restorative resins.
- Understanding the relationship between light activation energy and shrinkage is essential for optimizing clinical outcomes.
Purpose of the Study:
- To evaluate the immediate polymerization shrinkage of various restorative resins when activated by different light energy levels.
- To determine how variations in light energy affect volumetric shrinkage in dental composites.
Main Methods:
- Eight different dental composite resins were tested, including Z-100, Z-250, Ariston pHc, Filtek P-60, SureFil, Tetric Flow, Silux Plus, and F-2000.
- Polymerization shrinkage was measured using a capillary mercury dilatometer after an 80-second light activation.
- Light energy was regulated at two power densities: 350 mW/cm2 (Group I) and 275 mW/cm2 (Group II).
Main Results:
- A statistically significant difference in polymerization shrinkage was observed between the two light energy groups.
- Group I (350 mW/cm2) exhibited greater shrinkage (1.43%) compared to Group II (275 mW/cm2) (1.04%).
- Significant variations in shrinkage were also found among the different restorative materials tested.
Conclusions:
- Reducing light activation energy leads to a concomitant decrease in polymerization shrinkage for dental restorative resins.
- The degree of shrinkage reduction is influenced by the specific organic content and the physical-chemical properties of each material.
- Optimizing light curing parameters is crucial for minimizing polymerization shrinkage and improving the clinical performance of dental restorations.
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