Data sourcesPubMed, Medline via Ovid (1946 onward), EMBASE via Ovid (1947 onward), Scopus, Web of Science (Scientific Citation Index, Conference Indexes), dissertations and theses databases; Cochrane Collaboration (DARE, CDSR), NICE, SIGN, ClinicalTrials.gov; grey literature searching.Study selectionSix electronic databases were searched for terms related to hypodontia and treatment methods, and four further electronic databases searched using terms for hypodontia only. Mixed-method study designs were used with exclusion of case reports, case series with fewer than ten participants and nonsystematic reviews. Quality improvement reports were also included and managed separately. No language restrictions were used.Data extraction and synthesisData from each study were systematically extracted using a data extraction form modified from the Cochrane Public Health Group template. One reviewer completed data extraction, with a second reviewer checking for accuracy and consistency. Four outcome categories were developed to synthesise the studies using a novel categorisation approach based on the perspective of the study's evaluator; including three subjective outcomes (patient-reported, clinician-reported and lay-reported) and one objective outcome (clinical indicators). No synthesis of efficacy data was planned; therefore, a methodologic quality appraisal of studies was not undertaken.ResultsThe search identified 497 abstracts, from which 106 eligible articles were retrieved in full. Fifty-six studies and eight quality-improvement reports were included. Clinical indicators were reported in 49 studies (88%) including appearance, function, dental health, treatment longevity, treatment success and service delivery. Patient-reported outcomes were given in 22 studies (39%) including oral health-related quality of life, appearance, function, symptoms of temporomandibular dysfunction and patient experience. Clinician-reported and lay-reported outcomes were limited to appearance. Variability was seen in the tools used for measuring outcomes.ConclusionsThere is a lack of rationale and consistency in the selection of outcome measures used to evaluate hypodontia care. Outcomes are largely clinician and researcher-driven with little evidence of their relevance to patients. Evidence from hypodontia research is clinician-focused and likely to have limited value to support patients during decision-making. There is a need for a core-outcomes set with a patient-centric approach to drive improvements in health services.