Resumo BACKGROUND: School dental screening refers to visual inspection of children's oral cavity in a school setting followed by making parents aware of their child's current oral health status and treatment needs. Screening at school intends to identify children at an earlier stage than symptomatic disease presentation, hence prompting preventive and therapeutic oral health care for the children. This review evaluates the effectiveness of school dental screening in improving oral health status. OBJECTIVES: To assess the effectiveness of school dental screening programmes on overall oral health status and use of dental services. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 March 2017), the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Register of Studies, to 15 March 2017), MEDLINE Ovid (1946 to 15 March 2017), and Embase Ovid (15 September 2016 to 15 March 2017). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on language or publication status when searching the electronic databases; however, the search of Embase was restricted to the last six months due to the Cochrane Centralised Search Project to identify all clinical trials and add them to CENTRAL. SELECTION CRITERIA: We included randomised controlled trials (RCTs) (cluster or parallel) that evaluated school dental screening compared with no intervention or with one type of screening compared with another. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included six trials (four were cluster-RCTs) with 19,498 children who were 4 to 15 years of age. Four trials were conducted in the UK and two were based in India. We assessed two trials to be at low risk of bias, one trial to be at high risk of bias and three trials to be at unclear risk of bias.None of the six trials reported the proportion of children with untreated caries or other oral diseases.Four trials evaluated traditional screening versus no screening. We performed a meta-analysis for the outcome 'dental attendance' and found an inconclusive result with high heterogeneity. The heterogeneity was found it to be, in part, due to study design (three cluster-RCTs and one individual-level RCT). Due to the inconsistency, we downgraded the evidence to 'very low certainty' and are unable to draw conclusions about this comparison.Two cluster-RCTs (both four-arm trials) evaluated criteria-based screening versus no screening and showed a pooled effect estimate of RR 1.07 (95% CI 0.99 to 1.16), suggesting a possible benefit for screening (low-certainty evidence). There was no evidence of a difference when criteria-based screening was compared to traditional screening (RR 1.01, 95% CI 0.94 to 1.08) (very low-certainty evidence).In one trial, a specific (personalised) referral letter was compared to a non-specific one. Results favoured the specific referral letter with an effect estimate of RR 1.39 (95% CI 1.09 to 1.77) for attendance at general dentist services and effect estimate of RR 1.90 (95% CI 1.18 to 3.06) for attendance at specialist orthodontist services (low-certainty evidence).One trial compared screening supplemented with motivation to screening alone. Dental attendance was more likely after screening supplemented with motivation, with an effect estimate of RR 3.08 (95% CI 2.57 to 3.71) (low-certainty evidence).None of the trials had long-term follow-up to ascertain the lasting effects of school dental screening.None of the trials reported cost-effectiveness and adverse events. AUTHORS' CONCLUSIONS: The trials included in this review evaluated short-term effects of screening, assessing follow-up periods of three to eight months. We found very low certainty evidence that was insufficient to allow us to draw conclusions about whether there is a role for traditional school dental screening in improving dental attendance. For criteria-based screening, we found low-certainty evidence that it may improve dental attendance when compared to no screening. However, when compared to traditional screening there was no evidence of a difference in dental attendance (very low-certainty evidence).We found low-certainty evidence to conclude that personalised or specific referral letters improve dental attendance when compared to non-specific counterparts. We also found low-certainty evidence that screening supplemented with motivation (oral health education and offer of free treatment) improves dental attendance in comparison to screening alone.We did not find any trials addressing cost-effectiveness and adverse effects of school dental screening.