Effectiveness of Distal Shoe Space Maintainers for First Permanent Molar Eruption: A Systematic Review

Background: Premature loss of the second primary molars can result in arch space loss and later malocclusion. Distal shoe space maintainers (SMs) are used to guide the eruption of the permanent first molars, although their clinical effectiveness remains under-evaluated. Objective: We aimed to assess the clinical effectiveness and complication profile of distal shoe SMs in paediatric patients following premature loss of second primary molars. Methods: A PRISMA-compliant systematic review was conducted, with protocol registered in PROSPERO (CRD420251101518). Searches in PubMed, Scopus, Web of Science, Embase, and Cochrane Library identified clinical studies evaluating distal shoe appliances in children aged ≤6 years. Risk of bias was assessed using ROBINS-I and JBI tools. Results: Six clinical studies comprising 67 patients were included. Overall eruption success was 95.5% (64/67), with minor complications occurring in 25.4% of cases. Modified designs demonstrated fewer complications, although sample size was limited. Due to heterogeneity of methods and outcomes across studies, results are reported as descriptive metrics rather than inferential estimates. Conclusions: Distal shoe space maintainers are effective in promoting eruption of the first permanent molar with an acceptable complication profile. Their success depends heavily on technical execution and case selection. Further prospective studies with larger cohorts are required to validate optimal procedural parameters.