Biologic complications around dental implants may be categorized into peri-implant mucositis and peri-implantitis. Peri-implant mucositis is defined as reversible inflammation in the peri-implant mucosa without any apparent bone destruction. Peri-implantitis refers to inflammatory process that resulted in destruction of alveolar bone and attachment. Potential etiologic and contributing factors to both diseases are discussed in this review. By targeting and eliminating the etiologic factors nonsurgically as well as surgically, dental implants presenting with peri-implant diseases may be rescued, and then maintained with proper long-term peri-implant supportive therapy. Furthermore, clinical cases and their management are presented to demonstrate the available treatment options. Implant therapy should be carefully planned and executed with consideration of potential etiologic and contributing factors to developing biologic complications. During the initial consideration, patients should be informed of the potential biologic complications in dental implant therapy. Clinicians should monitor implants for any development or recurrence of peri-implant disease to ensure timely therapeutic intervention. Schlagwörter: bone loss, implant failure, implant success, peri-implant disease, periodontitis