Space changes after premature loss of mandibular second primary molars: a systematic review and meta-analysis.
Ahmed Kamal El-Motayam, Yousra Mohamed Abdel Rehim, Mais Medhat Sadek et al.
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In 30 seconds
This systematic review and meta-analysis assessed space changes after premature extraction of mandibular second primary molars in children aged 4–9 years. Four studies contributed to the qualitative review, and three studies involving 38 children were pooled. Mean mandibular space loss increased over follow-up, reaching 1.24 mm at 9–10 months post-extraction (95% CI: -1.48 to -1.02; p < 0.0001). The authors note that the evidence is limited and short term; whether this loss leads to later malocclusion or orthodontic treatment need is unknown.
Key findings
- Mean mandibular space loss was 0.80 mm at 3 months (95% CI: -1.00 to -0.60; p < 0.0001).
- Mean mandibular space loss was 1.10 mm at 6 months (95% CI: -1.24 to -0.96; p < 0.0001).
- At 9–10 months, mean mandibular space loss was 1.24 mm (95% CI: -1.48 to -1.02; p < 0.0001).
- Arch hemi-perimeter decreased by 1.06 mm at 6 months (95% CI: -1.26 to -0.31; p = 0.001).
Why it matters
The findings quantify short-term mandibular space changes after premature loss of a second primary molar, an outcome relevant to developing dentition. However, the review does not establish whether the measured loss predicts later malocclusion or orthodontic treatment. Recognising this uncertainty helps distinguish evidence of short-term dimensional change from evidence of long-term clinical consequences.
What to keep in mind
The evidence is limited: only three studies involving 38 children contributed to the meta-analysis, and follow-up was short. The review reports insufficient evidence for conclusions about the maxillary arch or long-term malocclusion and orthodontic treatment need.