A. Astanina1*, J. T. Koivisto1,2, M. Hannula1, T. Salminen3, M. Kellomäki1† and J. Massera1† 1Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland 2Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden 3Tampere Microscopy Center, Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland We investigated the interactions between the organic–inorganic phases in composites and the impact on in vitro dissolution.