Functional fillers for dental resin composites

Dental resin composites (DRCs) are popular materials to repair caries. Although various types of DRCs with different characteristics have been developed, restoration failures still exist. Bulk fracture and secondary caries have been considered as main causes for the failure of composites restoration. To address these problems, various fillers with specific functions have been introduced and studied. Some fillers with specific morphologies such as whisker, fiber, and nanotube, have been used to increase the mechanical properties of DRCs, and other fillers releasing ions such as Ag+, Ca2+, and F (-), have been used to inhibit the secondary caries. These functional fillers are helpful to improve the performances and lifespan of DRCs. In this article, we firstly introduce the composition and development of DRCs, then review and discuss the functional fillers classified according to their roles in the DRCs, finally give a summary on the current research and predict the trend of future development. Statement of significance Dental resin composites are widely-used restorative materials for dental caries. There are multiple requirements for their performance, safety and durability for them to serve in the complicated oral environment. The use of reinforced and functional fillers can improve the properties and performance of such materials. This is an up-to-date systematic review on the recent progress made on specialized filler materials fulfilling functions of mechanical reinforcement, remineralization, radiopacity, aesthetics, and self-healing and antibacterial characteristics. It should meet the need of researchers working in the field of dental materials and also in the general area of biomaterials and composites. (C) 2020 Published by Elsevier Ltd on behalf of Acta Materialia Inc.