Marginal Adaptation of Different Bulk-fill Composites: A Microcomputed Tomography Evaluation

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials Engineering

Background:

• Bulk-fill resin composites (RBCs) were developed to simplify dental restorations by allowing placement in thicker layers (4-5 mm).
• Evaluating their adaptation and marginal integrity is crucial for clinical success, especially in deep cavities.

Purpose of the Study:

• To assess the marginal adaptation and integrity of different bulk-fill resin composites (RBCs) compared to a conventional composite.
• To investigate the influence of aging on the performance of these materials in class II cavities.

Main Methods:

• Mesio-occlusal-distal cavities were prepared in human molars, with margins on enamel and dentin.
• Teeth were restored with three bulk-fill RBCs (SDR, FBF, TBF) or one conventional composite (CC).
• Restorations underwent aging (thermocycling and cyclic loading), followed by microcomputed tomography (µ-CT) analysis of interfacial gap volume.

Main Results:

• Smart Dentin Replacement (SDR) exhibited the smallest interfacial gap volume post-aging.
• Conventional composite (CC) showed good performance on enamel margins, while Tetric N-Ceram Bulk Fill (TBF) performed well on dentin margins.
• Filtek™ One Bulk Fill (FBF) demonstrated the largest gap volume, indicating poorer marginal adaptation.

Conclusions:

• Bulk-fill RBCs, particularly SDR, are suitable for deep class II cavities with dentin margins, offering an alternative to conventional layered RBCs.
• Further clinical studies are recommended to validate these findings in real-world patient scenarios.