1. Department of Oral and Maxillofacial Radiology, Umeå University, Umeå, and the Department of Logopedics and Phoniatrics, Karolinska Institutet, Stockholm, Sweden.
2. Department of Oral and Maxillofacial Surgery, Beijing Medical University, Beijing, China.
3. Department of Oral and Maxillofacial Radiology, Umeå University.