2.1 Sample

Enrollment was performed on medical records of periodontal compromised patients treated with implant prosthesis rehabilitations with at least 10 years of functional loading, who followed an individual maintenance program and supportive periodontal and peri‐implant treatment (SPT). This study was approved by ethical committee of the Sapienza University of Rome (Polyclinic Umberto I, Rome, Italy) with the resolution n. 546/19 and was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2013.

All patients signed a written informed consent and all the data collected were anonymized. A total of 1,991 implants (475 patients) were included in this study. All patients enrolled in this study lost teeth to periodontal disease.

Inclusion criteria were fully edentulous patients rehabilitated with a fixed complete denture (FCD) or overdentures, and patients treated with a fixed partial denture (FPD) and single‐tooth replacements.

Exclusion criteria were systemic diseases, poor oral hygiene, uncontrolled periodontal disease, severe intermaxillary skeletal discrepancy, bruxism, heavy smoking (20 cigarettes/day), drug and/or alcohol abuse, previous insertion and loss of implants, previous radiotherapy to the head and neck region for malignancy, treatment with antiblastic chemotherapy, chronic renal or liver disease, uncontrolled diabetes, hemophilia, bleeding disorder or anticoagulant therapy, metabolic bone disorder, immunocompromised state (including HIV), and mucosal disease, such as lichen planus. Clinical data with no measures of plaque index (PI) score, presence of bleeding on probing (BOP), and probing depth (PD) before treatment and during the follow‐up were excluded.