1. Department of Prosthodontics; Gerodontology and Oral Rehabilitation; Graduate School of Dentistry; Osaka University; Osaka Japan
2. Division of Dysphagia Rehabilitation; Graduate School of Medical and Dental Sciences; Niigata University; Niigata Japan
3. Clinic for Masticatory Disorders, Removable Prosthodontics and Special Care Dentistry; Center for Oral Medicine, Dental and Maxillo-Facial Surgery; University of Zurich; Zurich Switzerland