1. Department of Oral and Maxillofacial Diseases, Helsinki University Hospital, Helsinki University, 00014 Helsinki, Finland
2. Pushpagiri Institute of Medical Sciences and Research Centre, Medicity, Perumthuruthy, Tiruvalla 689101, Kerala, India
3. Department of Pathology, Helsinki University Hospital, Helsinki University, 00290 Helsinki, Finland
4. Faculty of Medicine, University of Basel, 4003 Basel, Switzerland
5. Department of Oral Diseases, Karolinska Institutet, Huddinge, 171 77 Stockholm, Sweden
6. Oral Health Institute, Hamad Medical Corporation, Doha P.O. Box 3050, Qatar
7. College of Dental Medicine, Qatar University, Doha P.O. Box 2713, Qatar