Resumo BACKGROUND: Poor or inequitable access to oral health care is commonly reported in high-, middle- and low-income countries. Although the severity of these problems varies, a lack of supply of dentists and their uneven distribution are important factors. Delegating care to dental auxiliaries could ease this problem, extend services to where they are unavailable and liberate time for dentists to do more complex work. Before such an approach can be advocated, it is important to know the relative effectiveness of dental auxiliaries and dentists. OBJECTIVES: To assess the effectiveness, costs and cost effectiveness of dental auxiliaries in providing care traditionally provided by dentists. SEARCH METHODS: We searched the following electronic databases from their inception dates up to November 2013: the Cochrane Effective Practice and Organisation of Care (EPOC) Group's Specialised Register; Cochrane Oral Health Group's Specialised Register; the Cochrane Central Register of Controlled Trials (Issue 11, 2013); MEDLINE; EMBASE; CINAHL; Cochrane Database of Systematic Reviews; Database of Abstracts of Reviews of Effectiveness; five other databases and two trial registries. We also undertook a grey literature search and searched the reference list of included studies and contacted authors of relevant papers. SELECTION CRITERIA: We included randomised controlled trials (RCTs), non-randomised controlled clinical trials (NRCTs), interrupted time series (ITSs) and controlled before and after studies (CBAs) evaluating the effectiveness of dental auxiliaries compared with dentists in undertaking clinical tasks traditionally performed by a dentist. DATA COLLECTION AND ANALYSIS: Three review authors independently applied eligibility criteria, extracted data and assessed the risk of bias of each included study and two review authors assessed the quality of the evidence from the included studies, according to The Cochrane Collaboration's procedures. Since meta-analysis was not possible, we gave a narrative description of the results. MAIN RESULTS: We identified five studies (one cluster RCT, three RCTs and one NRCT), evaluating the effectiveness of dental auxiliaries compared with dentists in providing dental care traditionally provided by dentists, eligible for inclusion in this review. The included studies, which involved 13 dental auxiliaries, six dentists, and more than 1156 participants, evaluated two clinical tasks/techniques: placement of preventive resin fissure sealants and the atraumatic restorative technique (ART). Two studies were conducted in the US, and one each in Canada, Gambia and Singapore.Of the four studies evaluating effectiveness in placing preventive resin fissure sealants, three found no evidence of a difference in retention rates of those placed by dental auxiliaries and dentists over a range of follow-up periods (six to 24 months). One study found that fissure sealants placed by a dental auxiliary had lower retention rates than one placed by a dentist after 48 months (9.0% with auxiliary versus 29.1% with dentist). The same study reported that the net reduction after 48 months in the number teeth exhibiting caries (dental decay) was lower for teeth treated by the dental auxiliary than the dentist (3 with auxiliary versus 60 with dentist, P value < 0.001).One study showed no evidence of a difference in dental decay after treatment with fissure sealants between groups. The one study comparing the effectiveness of dental auxiliaries and dentists in performing ART reported no difference in survival rates of the restorations (fillings) after 12 months.All studies were at high risk of bias and the overall quality of the evidence was very low, as assessed using the GRADE approach. In addition, four of the included studies were more than 20 years old; the materials used and the techniques assessed were out of date. We found no eligible studies comparing the effectiveness of dental auxiliaries and dentists in the diagnosis of oral diseases and conditions, in delivering oral health education and other aspects of health promotion, or studies assessing participants' perspectives including the acceptability of care received. None of the included studies reported adverse effects. In addition, we found no studies comparing the costs and cost-effectiveness of dental auxiliaries and dentists, their impact on access and equity of access to care that met the pre-specified inclusion criteria. AUTHORS' CONCLUSIONS: We only identified five studies for inclusion in this review, all of which were at high risk of bias and four were published more than 20 years ago, highlighting the paucity of high-quality evaluations of the relative effectiveness, cost-effectiveness and safety of dental auxiliaries compared with dentists in performing clinical tasks. No firm conclusions could be drawn from the present review about the relative effectiveness of dental auxiliaries and dentists.