Review: Status of Ester-Free Matrix Resins for Dental Composite Resins.

The chapter "Thiol-Ene Polymerization and Thiol-Michael Addition Polymerization" in the book "Expert Level of Dental Resins – Material Science & Technology" is expanded and updated in this article. As a result, a large portion of this article is the same as the chapter in the book. Ester-free monomers as matrix resins for dental composites were and are still a matter of interest. The fact is that for some dental applications, such as enamel or dentin adhesives, the ester bond’s hydrolytic stability seems to be in question. The ormocers and the siloranes were the first classes of ester-free filling resin composites. Contrary to the ormocers, which are still marketed, the sale of the siloranes was discontinued around 2017 noiselessly and without giving any reason. Presently dental research of tooth adhesives is predominantly focused on identifying degradation-stable adhesion promotors that are based on ester-free monomers. This article introduces the thiol-ene polymerization and the thiol-Michael addition polymerization to obtain ester-free polymeric networks suitable as matrices for resin composites.