Inclusion Criteria:  •> 20 years of age  Presence of ≥1 adjacent missing teeth, in either maxilla or mandible (up to three missing units). A natural tooth had to be present mesially to the most proximal implant site, although free end situations were allowed, and opposing dentition had to be natural teeth or implant supported fixed restorations. History of treated and controlled periodontitis. Presence of adequate bone volume to achieve primary implant stability without concomitant regeneration  Exclusion Criteria:  Diseases affecting bone metabolism or wound healing (e.g.) History of radiation therapy, leukocyte dysfunction, or any other immunodeficiency Drug abuse Intrasurgical exclusion criteria, such as the lack of primary stability, the need of bone augmentation or the impossibility of placing the implant based on prosthetic requirements. �