1. Institute of Dentistry; Department of Cariology, Endodontics, Pediatric Dentistry and Clinical Genetics; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen; Denmark
2. Department of Cariology; Restorative Sciences and Endodontics; School of Dentistry; University of Michigan; Ann Arbor; Michigan; USA
3. Department of Preventive and Restorative Dental Sciences; School of Dentistry; University of California, San Francisco; California; USA