Space changes after premature loss of mandibular second primary molars: a systematic review and meta-analysis

Deciduous dentition plays a crucial role in mastication, phonetics, and maintaining arch space for permanent successors. While several systematic reviews have quantified spatial changes following first primary molar loss, specific evidence synthesis for second primary molars is lacking. This systematic review and meta-analysis aimed to quantify space loss following premature extraction of second primary molars and evaluate the clinical necessity of space maintenance.

Five electronic databases (PubMed, Web of Science, LILACS, EMBASE, and Cochrane libraries) were searched without date restrictions (last search 03/06/2025). Inclusion criteria included randomized, quasi-randomized, and non-randomized clinical trials involving children aged 4-9 years with second primary molar indicated for extraction. Two independent investigators assessed studies for inclusion, evaluated risk of bias using ROBINS-I tool, and extracted data. Random-effects models with 95% confidence intervals calculated mean differences as effect measures.