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Updated: May 1, 2026
08:45
Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation
Published on: July 21, 2014
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Vertical and horizontal polymerization shrinkage in composite restorations.
Masao Irie1, Jiro Tanaka1, Yukinori Maruo2
1Department of Biomaterials, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8525, Japan.
Summary
Vertical polymerization shrinkage in light-curing composites correlates with horizontal shrinkage and impacts bond strength. Minimizing vertical shrinkage improves adhesion to enamel and dentin, crucial for dental restorations.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Biomaterials Engineering
Background:
- Light-curing composite restorative materials are widely used in dentistry.
- Polymerization shrinkage is an inherent property of these materials, occurring in multiple directions.
- Understanding shrinkage behavior is critical for predicting material performance and longevity in clinical applications.
Purpose of the Study:
- To investigate the relationship between vertical and horizontal polymerization shrinkage in resin composites.
- To evaluate the effects of these shrinkage dimensions on dimensional changes within tooth cavities.
- To assess the impact of shrinkage on shear bond strengths to tooth substrates (enamel and dentin) and marginal gap formation.
Main Methods:
- Measurements of vertical and horizontal polymerization shrinkage were taken in tooth cavities immediately after light activation (3 minutes).
- Shear bond strengths to enamel and dentin were determined using the same time frame.
- Marginal gap widths were assessed in a non-reacting Teflon mold under identical conditions.
Main Results:
- A significant positive correlation was found between vertical and horizontal polymerization shrinkage in tooth cavities (r=0.647, p=0.043).
- Materials exhibiting lower vertical shrinkage also showed reduced horizontal shrinkage and demonstrated higher shear bond strengths to both enamel (r=-0.697, p=0.025) and dentin (r=-0.752, p=0.012).
- Smaller horizontal shrinkage correlated with reduced marginal gap widths in the Teflon mold (r=0.829, p=0.003).
Conclusions:
- Vertical and horizontal polymerization shrinkage are significantly correlated during the initial setting phase (<3 min) of light-activated composites in tooth cavities.
- Minimizing vertical shrinkage is a key factor for enhancing the adhesive properties of composite restorations to enamel and dentin.
- The findings highlight the importance of controlling polymerization shrinkage for improving the clinical performance and durability of dental composite materials.
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