Effectiveness of primary school-based interventions in improving oral health of children in low- and middle-income countries: a systematic review and meta-analysis

BACKGROUND: Risk factors for oral disease can potentially be ameliorated by school-based interventions. This review evaluates the effectiveness of primary school-based interventions in improving oral health among children in low-and middle-income countries (LMICs). METHODS: Our systematic review was conducted in accordance with the Joanna Briggs Institute methodology for systematic reviews of effectiveness. Medline, Embase, Global Health, CINAHL, Emcare, Scopus, Web of Science, WHO website, Google Advanced and Google Scholar were searched for experimental and observational studies published between 1995 and 2021 in English. Quality assessment and data extraction of the articles were performed by two independent reviewers. The primary outcome was decayed, missing, and filled teeth/surfaces [dmft(s)/DMFT(S)] scores. Seven meta-analyses were conducted. RESULTS: The search yielded 1178 publications and after removing duplicates, 753 remained. A further 648 publications were excluded after screening titles and abstracts. 105 publications were reviewed in full and 34 were included. Narrative synthesis showed school-based interventions had a positive effect on oral health outcomes. Meta-analysis showed a significant positive effect on dental caries measured by DMFT scores (standardised mean difference (SMD) = − 0.33; 95% CI − 0.56 to − 0.10; P = 0.005), net increment in DMFS scores (SMD = − 1.09; 95% CI − 1.91 to − 0.27; P = 0.009), dmft and DMFT/S score > 1 (Risk Ratio = 0.70; 95% CI 0.53 to 0.94; P = 0.02) and plaque scores (SMD = − 0.32; 95% CI − 0.46 to − 0.18; P < 0.00001). Non-significant positive effect was observed for dental caries measured by net increment in DMFT scores (SMD = − 0.34; 95% CI − 0.69 to 0.02; P = 0.06) and DMFS scores (SMD = − 0.26; 95% CI − 0.70 to 0.18; P = 0.24), and gingival health (SMD = 0.12; 95% CI − 0.32 to 0.55; P = 0.60). Certainty of evidence was assessed as very low for all oral health outcomes. CONCLUSION: School-based interventions can be effective in reducing the burden of oral disease among primary school children in LMICs, with skills-based education, teacher training, provision of access to oral health services and parental engagement emerging as particularly promising. Further research is required to provide evidence of effectiveness of primary school-based interventions to improve oral health. Systematic review registration The title of this review was registered with PROSPERO (registration number: CRD42020202599). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12903-022-02291-2.