3D mapping of polymerization shrinkage using X-ray micro-computed tomography to predict microleakage

Area of Science:

• Biomaterials Science
• Dental Materials
• Imaging Techniques

Background:

• Polymerization shrinkage and microleakage are critical factors affecting the longevity of dental restorations.
• Accurate, non-destructive methods are needed to quantify these phenomena.
• X-ray micro-computed tomography (microCT) offers high-resolution imaging capabilities.

Purpose of the Study:

• To validate X-ray micro-computed tomography (microCT) for precise, non-destructive assessment of polymerization shrinkage and microleakage in dental composites.
• To investigate the influence of sample geometry, including C-factor and volume, on these parameters.

Main Methods:

• Dental composites were placed in model cavities with controlled C-factors and volumes.
• microCT imaging was performed before and after photopolymerization to determine volume changes (shrinkage).
• Microleakage was assessed by analyzing gap formation and validated with dye penetration tests.

Main Results:

• Polymerization shrinkage was consistent across different sample geometries.
• Microleakage was significantly influenced by C-factor and composite volume, increasing with higher values.
• microCT-derived microleakage patterns correlated well with dye penetration results.

Conclusions:

• microCT is a powerful, non-destructive tool for quantifying polymerization shrinkage and microleakage in dental composites.
• Sample geometry plays a crucial role in determining microleakage, but not polymerization shrinkage.