Conditional Mitigation of Dental-Composite Material-Induced Cytotoxicity by Increasing the Cure Time

Area of Science:

• Biomaterials Science
• Dental Materials
• Cell Biology

Background:

• Light-cured composite resins are standard in dental restorations.
• Residual monomers in composites can be cytotoxic, impacting biocompatibility.
• Optimizing curing time is crucial for reducing cytotoxicity but remains experimentally undetermined.

Purpose of the Study:

• To investigate the biocompatibility of flowable and bulk-fill dental composites cured for varying durations.
• To assess the impact of cell proximity (direct contact vs. close proximity) on material cytotoxicity.
• To determine if extended curing times enhance fibroblast survival and attachment.

Main Methods:

• Human gingival fibroblasts were cultured with flowable and bulk-fill composites.
• Composites were cured for 20, 40, 60, and 80 seconds.
• Cell behavior was evaluated based on direct contact and proximity to materials.
• Pre-cured milled acrylic served as a control group.

Main Results:

• No fibroblast survival was observed in direct contact with either composite type, irrespective of curing time.
• Fibroblast survival near bulk-fill composites increased with longer curing times, but remained below 20% of control.
• Surface layer removal offered minor biocompatibility improvements, not consistently correlated with cure time.

Conclusions:

• Dental composites exhibit significant cytotoxicity to directly contacting fibroblasts, regardless of curing duration.
• Extended curing times mitigate cytotoxicity for bulk-fill composites in proximity, but not for flowable types.
• Optimizing composite biocompatibility depends on material type, cell location, and surface finish, offering clinical insights.