Department of Restorative Dentistry, Paediatric Dentistry and Periodontology
University of Munich, Germany
After 73 countries and the EU have become party of the Minamata convention and ratified it has become active in 2017. Each country who has agreed to be legally bound by the convention must take at least two measures from that list as it relates to phasing down the use of dental amalgam. Dental associations, universities, industry and insurances are asked to develop mercury-free alternatives, improve prevention and minimum intervention approaches and change education and reimbursement.
GIC and composites are the most used alternative materials. In the last years a new group of composite resin filling materials was introduced called bulk fill composites. These materials are recommended to be placed in one layer even in larger cavities up to 4-5 mm and the time-consuming and demanding incremental technique would be no longer necessary.
There are quite big differences in matrix, initiator, particle size and filler amount of these bulk fill materials and hence also in macro-, micro- and nanomechanical properties (e.g. shrinkage stress, flexural strength, E-modulus, Vickers hardness, translucency, etc.).
Traditional GIC are easily to use and can also be placed in bulk and would be an alternative especially in deciduous teeth. But flexural strength is low compared to bulk fill composites and more fractures occur in permanent teeth. Up to now only for few materials clinical data are available but for one material already 10 years. Nevertheless, more long-term in-vivo results of this new group of composite resins and GIC are desirable.