Dr. Zahra Ebrahimi Nik — Orthodontist, Niavaran Tehran

Does Early Orthodontic Treatment in Mixed Dentition Improve Long-Term Outcomes? A Systematic Review and Meta-Analysis

Yousef Majed Almugla, Madiraju Guna Shekhar (Medicina) — 2025-10-16 — 11 minutes

This systematic review and meta-analysis (Medicina, 2025) evaluated whether early orthodontic treatment in children aged 6–12 years during mixed dentition leads to better long-term skeletal and dental outcomes than delayed or no treatment. Eighteen studies were included (15 RCTs, 2 CCTs, 1 cohort); nine provided data on overjet, six on ANB angle, and four on PAR score. Meta-analyses showed no statistically significant long-term differences between early treatment and control groups for overjet, ANB angle, or PAR scores; heterogeneity was substantial. Early treatment improved occlusal parameters in the short term, but benefits did not consistently persist. GRADE certainty was moderate for overjet and ANB, low for PAR. The authors conclude that early intervention should be selective (e.g. functional crossbite, trauma risk, psychosocial need) rather than routine.

Background and objectives

Early orthodontic intervention during mixed dentition (ages 6–12) is used to intercept developing malocclusions and potentially reduce later complexity. Evidence on long-term stability compared with delayed or no treatment is limited and conflicting. This review (Medicina, 2025) synthesizes evidence on long-term skeletal and dental outcomes after early treatment versus delayed or no intervention.

Methods

The protocol was registered in PROSPERO (CRD420251028446). Searches were conducted in PubMed, Scopus, Web of Science, and Google Scholar (1995–April 2025). Eligible studies were RCTs, controlled clinical trials, or cohort studies with ≥1 year post-treatment follow-up; interventions were fixed or removable appliances in mixed dentition; comparators were no treatment or delayed treatment. Primary outcomes: overjet (mm), ANB angle (°), and PAR score. Meta-analyses used a random-effects model; certainty of evidence was assessed with GRADE.

Results

Eighteen studies were included (15 RCTs, 2 CCTs, 1 cohort). Nine studies contributed to overjet meta-analysis, six to ANB, four to PAR. Pooled results showed no statistically significant long-term differences between early treatment and control for overjet (SMD −0.18, 95% CI −0.96 to 0.59), ANB angle (SMD −0.12, 95% CI −0.44 to 0.69), or PAR score (SMD 0.19, 95% CI −0.25 to 0.63). Heterogeneity was high (I² 79–96%). Short-term improvements in overjet, ANB, and PAR were often not sustained; relapse and variability in retention protocols were noted. Certainty was moderate for overjet and ANB, low for PAR.

Conclusions and clinical relevance

Early orthodontic treatment in mixed dentition provides short-term improvements but current evidence does not support consistent long-term benefits over delayed intervention. Routine early treatment for long-term stability alone is not supported. Early intervention may be appropriate in selected cases: functional crossbite, increased risk of dental trauma, or psychosocial concerns. Decisions should be individualized; long-term monitoring is important.

Reference: Almugla YM, Shekhar MG. Medicina (Kaunas). 2025;61(10):1854. PMC12565956. https://pmc.ncbi.nlm.nih.gov/articles/PMC12565956/

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