Incremental and Bulk-fill Techniques With Bulk-fill Resin Composite in Different Cavity Configurations

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Biomaterials Engineering

Background:

• Dental composite restorations are crucial for tooth repair.
• Understanding polymerization stress and its impact on bond strength is vital for longevity.
• Bulk-fill and incremental techniques present different clinical advantages and challenges.

Purpose of the Study:

• To compare microtensile bond strengths (μ-TBS) of incremental versus bulk-fill composite techniques.
• To evaluate the influence of C-factor (cavity configuration ratio) and cavity wall compliance on bond strength.
• To assess the performance of two specific bulk-fill composite materials.

Main Methods:

• Human third molars were prepared with Class I and MOD cavities, including high compliance variations.
• Cavities were restored using incremental or bulk-fill techniques with two distinct bulk-fill composites.
• Microtensile bond strengths were measured, and polymerization stresses were calculated.
• Statistical analysis included Kruskal-Wallis test and Weibull analysis.

Main Results:

• Incremental technique yielded significantly higher μ-TBS than bulk-fill in high C-factor (Class I) cavities.
• No significant difference in μ-TBS between techniques was found in low C-factor (MOD, high compliance) cavities.
• High C-factor cavities exhibited significantly lower μ-TBS than low C-factor cavities.
• No significant difference in μ-TBS was observed between the two bulk-fill materials tested.

Conclusions:

• Incremental technique is superior for bond strength in high C-factor scenarios.
• Cavity configuration and compliance significantly influence the effectiveness of different placement techniques.
• Bulk-fill composites may offer comparable bond strength to incremental techniques in less demanding cavity configurations.