1. Department of Neurosciences, Reproductive and Odontostomatological Sciences, Division of Fixed Prosthodontics, “Federico II” University of Naples, 80100 Naples, Italy
2. Department of Medical Biotechnologies, Division of Fixed Prosthodontics, University of Siena, 53100 Siena, Italy
3. Department of Surgical and Morphological Sciences, Dental School, University of Varese, 21100 Varese, Italy