Background
Resin composites are popular materials to fill tooth cavities due to their esthetics and direct-filling capabilities. However, the materials are susceptible to micro-cracking brought on by thermal and mechanical stresses resulting from strong occlusal (chewing and clenching) forces. These micro-cracks can result in secondary caries formation and bulk fracture of the composite materials, limiting the service lifetime of dental restorations. Repair usually requires complete replacement of the resin filler material. While calcium and phosphate-releasing composites have been developed to mitigate caries formation, such materials typically have low mechanical strengths. There is therefore continued interest in developing composites capable of reducing caries formation, while simultaneously providing improved mechanical strength.