1. Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, Mich.
2. Center of Implantology, Oral and Maxillofacial Surgery (CICOM), Badajoz, Spain.
3. Department of Oral Surgery and Implantology, The International University of Catalonia, Barcelona, Spain.
4. Department of Oral Surgery and Implantology, University of Granada, Granada, Spain.
5. Department of Mathematics, University of Extremadura, Badajoz, Spain.