Polymerization shrinkage and spherical glass mega fillers: effects on cuspal deflection

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Dental composite resins are widely used restorative materials.
• Polymerization of dental composites induces significant contraction stress.
• This stress can lead to marginal gaps, secondary caries, and debonding.

Purpose of the Study:

• To evaluate the efficacy of spherical glass mega fillers (SGMF) in mitigating polymerization contraction stress in dental composite resins.
• To assess the impact of different SGMF diameters on reducing cuspal deflection in a simulated cavity model.

Main Methods:

• Twenty stylized MOD cavities were prepared in acrylic resin and treated adhesively.
• Composite resins were filled with and without SGMFs of varying diameters (1mm, 1.5mm, 2mm).
• Digital image analysis measured cuspal deflection before and after polymerization; ANOVA was used for statistical analysis.

Main Results:

• A significant reduction in cavity wall deflection was observed when using composite resins with SGMFs.
• The smallest diameter SGMFs (1mm) yielded the most substantial reduction in contraction stress.
• The number of SGMFs varied based on diameter to maintain consistent volume.

Conclusions:

• Spherical glass mega fillers are effective in reducing contraction stress in dental composite resins.
• Optimizing SGMF size and incorporation can enhance the clinical performance and longevity of dental restorations.