IADR Abstract Archives
Design and Preparation of Self-healing Dental Composites
Objectives: Micro-cracks in dental resin composite restorative are very difficult to detect and repair manually. Left untreated, their propagation will eventually lead to failure of the composite. The objective of this project is to design and prepare a clinically applicable self-healing dental composite (SHDC) that can heal micro-cracks autonomously.
Methods: SHDCs were made by healing-powder (fluoro aluminosilicate glass particles) and healing-liquid (polyacrylic acid) encapsulated into silica microcapsules and mixing these microcapsules with traditional dental resin composites. Composites are comprised of a resin (Bis-GMA and 2-hydroxyethyl methacrylate), glass fillers, and silane coupling agents (to enhance filler/resin bonding). Successful encapsulation of healing-liquid was confirmed by thermogravimetric analysis, FTIR and SEM. The elastic modulus, flexural strength, and fracture toughness of SHDCs containing (2.5-10) mass % microcapsules were evaluated by using a 3-point bending fixture. The healing efficiency of the SHDCs was expressed as the percentage of fracture toughness recovered after healing. Morphological and chemical changes at the fracture surface before and after healing were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Filtek Z250 and experimental composites formulated with microcapsules containing water instead of healing-liquid were used as controls. One-way ANOVA with a 95% confidence interval was used to indicate significant differences (n=5) between the experimental groups.
Results: The elastic modulus of the SHDCs ranged from 10.0 to 12.3 GPa, equal or greater than that of the Z250 (10.3±1.1GPa) . At only 5 mass % of healing-liquid containing microcapsules, the SHDCs reached, on average, 24.2±3.8% healing efficiency, over two times higher than controls. An increase to 10 mass % of microcapsules reduced the elastic modulus and fracture toughness of the composite, but only provided 1% increase in healing efficiency.
Conclusions: A new type of dental resin composites that can autonomously heal micro-cracks was successfully prepared.
Methods: SHDCs were made by healing-powder (fluoro aluminosilicate glass particles) and healing-liquid (polyacrylic acid) encapsulated into silica microcapsules and mixing these microcapsules with traditional dental resin composites. Composites are comprised of a resin (Bis-GMA and 2-hydroxyethyl methacrylate), glass fillers, and silane coupling agents (to enhance filler/resin bonding). Successful encapsulation of healing-liquid was confirmed by thermogravimetric analysis, FTIR and SEM. The elastic modulus, flexural strength, and fracture toughness of SHDCs containing (2.5-10) mass % microcapsules were evaluated by using a 3-point bending fixture. The healing efficiency of the SHDCs was expressed as the percentage of fracture toughness recovered after healing. Morphological and chemical changes at the fracture surface before and after healing were assessed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Filtek Z250 and experimental composites formulated with microcapsules containing water instead of healing-liquid were used as controls. One-way ANOVA with a 95% confidence interval was used to indicate significant differences (n=5) between the experimental groups.
Results: The elastic modulus of the SHDCs ranged from 10.0 to 12.3 GPa, equal or greater than that of the Z250 (10.3±1.1GPa) . At only 5 mass % of healing-liquid containing microcapsules, the SHDCs reached, on average, 24.2±3.8% healing efficiency, over two times higher than controls. An increase to 10 mass % of microcapsules reduced the elastic modulus and fracture toughness of the composite, but only provided 1% increase in healing efficiency.
Conclusions: A new type of dental resin composites that can autonomously heal micro-cracks was successfully prepared.