1. Department of Prosthodontics; Faculty of Odontology, Malmö University; Malmö Sweden
2. Department of Biomaterials; Institute of Clinical Sciences, Gothenburg University; Gothenburg Sweden
3. Department of Oral Pathology; Faculty of Odontology, Malmö University; Malmö Sweden
4. Department of Prosthodontics; Sahlgrenska Academy, Gothenburg University; Gothenburg Sweden