ObjectivesTo evaluate outcome measures, methods of assessment, and analysis in clinical studies on the prevention and management of peri‐implant mucositis and peri‐implantitis.MethodsSystematic electronic searches (CENTRAL/MEDLINE/SCOPUS) up to April 2021 were conducted to identify longitudinal clinical studies with ≥10 patients on either the prevention or management of peri‐implant diseases. Outcome measures of this analysis were the choice of outcome measures, methods of assessment, and analytical methods. Risk of bias was evaluated according to study design. Data were extracted into evidence tables and outcomes were analysed in a descriptive manner.ResultsThe analysis of the 159 selected studies revealed that probing pocket depth (PPD) and bleeding/suppuration on probing (BOP) were reported in 89% and 87% of all studies, respectively. Additional outcome measures included plaque scores (reported in 64% of studies), radiographic outcomes (49%), soft tissue dimensions (34%), and composite outcomes (26%). Adverse events (8%) and patient‐reported outcomes (6%) were only rarely mentioned. A primary outcome measure was clearly defined only in 36% of studies. Data on PPD, radiographic outcomes, and soft tissue dimensions were primarily reported as mean values and rarely as frequency distributions. For radiographic outcomes and soft tissue dimensions, it was frequently unclear how clustered data were handled.ConclusionsPPD and BOP were routinely reported in studies on the prevention and management of peri‐implant mucositis and peri‐implantitis, while composite outcomes, adverse events, and patient‐reported outcomes were only infrequently described.