Dental composite resins are often favoured as direct dental restorative material due to their aesthetic quality, and they are increasingly replacing the controversial mercury-based amalgams. However, the commonly used dental composite resins present several important drawbacks, most importantly polymerisation shrinkage and the possibility of potentially toxic chemicals such as bisphenol A leaching out of the fillings. These problems have led to great interest in the development of improved composite resins. This review discusses the advantages and problems of currently-used resins, then focuses on recent developments, outlining several strategies aimed at improving the properties of dental resins. Finally, this review highlights the use of natural compounds for the development of dental resins, which is an emerging trend in the design of materials for bio-medical applications where biocompatibility is essential.