Rehabilitation of full-arch edentulism with fixed or removable dentures retained by root-form dental implants: A systematic review of outcomes and outcome measures used in clinical research in the last 10 years

Aim To evaluate outcome measures, methods of assessment, and analysis in clinical studies on the rehabilitation of full-arch edentulism with implant-supported fixed or removable prostheses. Materials and Methods A protocol-oriented search was conducted in MEDLINE via PubMed, EMBASE, and Cochrane Library (PROSPERO registration CRD42021265179) from 1 January 2011 to 27 July 2021 to identify longitudinal studies reporting on the rehabilitation of edentulous patients with implant-supported prostheses. The primary aim of this study was the collection of all objectively reported outcomes in each study. Secondary aims included the description of the methods of assessment and analytical methods. Risk of bias was applied according to the study design (randomized controlled trial, cohort study, or descriptive pre-post study). Individual study data were extracted into an outcomes matrix. Outcomes were grouped into domains and descriptively analysed. A network diagram was generated to establish relationships between domains. The present review follows the PRISMA statement. Results The screening and selection processes resulted in the identification of 491 publications, corresponding to 421 different studies (cohorts of patients). Only 24% of the studies reported the use of EQUATOR network guidelines. Implant failure/survival was the most reported outcome (270 studies), but the criterion to determine implant failure and/or survival was frequently not described or was ambiguous. Implant success was much less frequently reported (88) and was based on several heterogenous composite definitions. Marginal bone levels (233 studies), technical complications (158), and clinical outcomes (150), including peri-implant soft tissue and implant stability assessment, were also frequently reported. Patient-reported outcome measures (PROMs) (145) and function-based outcomes (40) were predominantly reported in isolation from other outcomes and most frequently in removable restorations. While quality of life was evaluated using valid instruments, patient satisfaction was evaluated based on a common sense concept of satisfaction. Economic outcomes were under-reported (13). Conclusions There is great heterogeneity in the criteria to define implant failure or survival and implant success, which prevents the comparison of rates across studies. Even though studies frequently report multiple outcomes, PROMs are usually reported in isolation from other outcomes. It would be valuable to have a set of core outcome variables and standardized methods of measurement for future studies.