1. Unit of Periodontology, Department of Biomedical, Surgical and Dental Sciences, University of Milan, Foundation IRCCS Cà Granda, 20142 Milan, Italy
2. Department of Periodontics and Oral Medicine and Michigan Center for Oral Health Research, Ann Arbor, MI, USA
3. Department of Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI, USA