1. Pain Therapy Unit, Department of Oncology, Azienda Ospedaliero-Universitaria Pisana, Via Roma 67, 56127 Pisa, Italy
2. Department of Head and Neck, Azienda Ospedaliero-Universitaria Pisana, Via Roma 67, 56127 Pisa, Italy
3. Department of Dentistry, University of Pavia, Via Ferrara 1, 27100 Pavia, Italy