Effect of the Abutment-Prosthesis Connection on Marginal Bone Loss and Gingival Sealing Around Dental Implants

Inclusion criteria: * Kennedy class I or II (unilateral or bilateral free end) or III (posterior intermediate edentulous section) mandibular requiring 2 implants to restore at least 2 molars, 2 molars and 1 premolar, or 2 premolars and 1 molar. * Possibility of placing a transgingival abutment at least 2 mm high. Exclusion criteria: * Need for simultaneous bone augmentation. * Heavy smokers (\>10 cigarettes/day). * Uncontrolled type 1 or 2 diabetes (HgA1c\>8). * Known autoimmune or inflammatory disease. * Serious blood disorders, such as hemophilia or leukemia. * Local or systemic infection that may compromise normal healing (e.g., extensive periapical pathology). * Liver or kidney dysfunction/failure. * Currently receiving cancer treatment or within 18 months from completion of radio- or chemotherapy. * Long-term history of oral bisphosphonates use (i.e., 10 years or more). * History of intravenous bisphosphonates. * Long-term (\>3 months) history of antibiotics or drugs known to alter the inflammation and/or immunological system 3 months before inclusion. * Severe osseous diseases (e.g., Paget disease of bone). * Pregnant women or nursing mothers. * Not able or not willing to follow instructions related to the study procedures.