PNG University Gainesville, Virginia, United States
Introduction: This study explores the enhancement of fatigue resistance in self-healing dental composites. By incorporating innovative materials and methods, we aim to improve the durability and longevity of these composites under cyclic loading conditions. Our findings demonstrate significant advancements in the self-healing capabilities and overall performance of dental composites, contributing to more resilient and long-lasting dental restorations.
Materials and
Methods: The self-healing dental composite was prepared by mixing Bis-GMA and TEGDMA in a 70:30 weight ratio, incorporating 2 wt% of microencapsulated dicyclopentadiene (DCPD) and 1 wt% Grubbs catalyst for self-healing capabilities. Silica nanoparticles (average size 20 nm) and barium glass particles (average size 1-3 µm) were treated with a silane coupling agent to ensure compatibility with the resin matrix, achieving a 60 wt% filler loading. The composite mixture was then poured into molds and cured under blue light (450-470 nm) for 40 seconds per side. Cured specimens underwent cyclic loading fatigue testing using a universal testing machine, with a sinusoidal load between 10 N and 50 N at a frequency of 2 Hz, recording the number of cycles until failure. Controlled microcracks were introduced using a mechanical indenter, and specimens were stored at 37°C for 24 hours to facilitate self-healing. Post-healing, specimens were re-tested under the same cyclic loading conditions to compare fatigue life. Characterization techniques included SEM for microstructural analysis, FTIR for chemical verification of healing, and DMA for assessing mechanical properties. Statistical analysis was conducted using t-tests with a 95% confidence level to determine the significance of the improvements in fatigue resistance post-healing.
Results, Conclusions, and Discussions: Results, Conclusions, and Discussions
The results demonstrated a significant enhancement in the fatigue resistance of the self-healing dental composite. Specimens subjected to cyclic loading exhibited an increase in fatigue life by approximately 30% post-healing. SEM analysis revealed effective crack closure, supported by FTIR spectra showing characteristic peaks corresponding to the polymerized healing agent. DMA results confirmed that the mechanical properties of the healed specimens closely matched those of the original composite. The self-healing capability effectively mitigated microcrack propagation, thereby extending the functional lifespan of the dental composite. These findings suggest that incorporating microencapsulated healing agents into dental composites is a promising strategy for enhancing durability and reducing the need for frequent dental restorations. Future research should focus on optimizing the healing agent concentration and exploring long-term performance under clinical conditions.
Acknowledgements (Optional): This research was supported in part by the Oklahoma Center for the Advancement of Science and Technology (HR13-131). The authors would also like to express their gratitude to Esstech for generously donating materials used in this research. Additionally, special thanks to Professor Michael W. Keller at The University of Tulsa, Mechanical Engineering, Tulsa, USA, and Professor Khajotia at the University of Oklahoma Health Sciences Center, Oklahoma City, USA, for their valuable contributions and guidance throughout the study.
