1. Department of Surgical and Morphological Science, Dental School, University of Varese, 21100 Varese, Italy
2. Private Practice, 00193 Rome, Italy
3. Private Practice, 20154 Milan, Italy
4. Department of Health Sciences, University of Eastern Piedmont, 28100 Novara, Italy
5. Mir Dental Hospital, 149-132 Samduk 2Ga, Jung-Gu, Daegu 700 412, Republic of Korea
6. Department of Dental Sciences, Vita Salute San Raffaele University, 20132 Milan, Italy