Objective To evaluate the effectiveness of school dental screening in improving oral health status and the use of dental services. This review is an update of the original review published in 2017. As you would expect of a Cochrane review, the methodology was of high quality.Study selection Inclusion criteria: randomised controlled trails (RCTs) that evaluated school dental screening compared with no intervention or with another type of screening. The outcome of six of the trials presented dental attendance as the main outcome, while one trail (Nelson 2019) measured the main outcome as receipt of dental care. The studies had an average follow-up period of three to four months, with none reporting on the long term. A total of 3,093 records were identified in the initial search. Twenty-seven full-text copies were requested, and 17 reports and one ongoing study were excluded. Seven studies met the inclusion criteria (reported in nine articles).Results The systematic review included seven trials (four from the UK, two from India and one from the USA) involving 20,192 children aged 4-15 years. Based on the Cochrane risk of bias tool, two trials were determined to be at low risk of bias, two trials were high risk of bias and three trials were assessed to be at unclear risk of bias. Due to the inconsistency in evidence, the review was unable to draw conclusions between traditional screening versus no screening. The comparison between criteria-based screening versus no screening was evaluated, showing a pooled effect estimate of RR 1.07 (95% CI 0.99 to 1.16), which suggested a possible benefit for screening. Criteria-based screening was compared to traditional screening (RR 1.01, 95% CI 0.94 to 1.08), with no evidence of a difference in effectiveness. No trials reported on the potential adverse effects of school dental screening programmes.Conclusion The systematic review found there was very low certainty of evidence to support the role of school screening programmes in improving dental attendance. There was a low certainty of evidence to conclude that criteria-based screening, personalised referral letters or screening supplemented with motivation improve dental attendance.