Facial soft tissue changes in patients following rapid maxillary expansion in children: A systematic review
Bibliographic record
Abstract
BACKGROUND: Non-surgical rapid maxillary expansion (RME) has been widely investigated regarding skeletal effects, although fewer studies have assessed the associated soft tissue changes, which is an important factor to consider, as orthodontic treatment aims to achieve occlusal harmony and an aesthetically pleasing soft tissue balance. This systematic review examines the existing literature on facial soft tissue changes following rapid maxillary expansion (RME) in children with a maxillary transverse deficiency. MATERIAL AND METHODS: A systematic search was conducted up to July 2025 in four major databases, including Embase (via Ovid), Medline (via Ovid), PubMed, Cochrane Library, and Google Scholar. Studies focused on children receiving RME were included. The risk of bias was assessed using the Revised Cochrane risk-of-bias tool for randomized trials and the ROBINS-I tool for the Risk of Bias in Non-randomized Studies of Interventions. This review followed the protocols recommended by the Preferred Reporting Items for a Systematic Review and Meta-analysis (PRISMA) guidelines. RESULTS: Of the 1379 articles found, 15 included PICOS-based inclusion criteria: five randomized controlled trials, four cohort studies, and six controlled clinical trials. Alar width (0.5 to 2.21mm), alar base width (0.17 to 2.81mm), and nasolabial angle (0.9 degrees) increased significantly after RME treatment. Five studies were found to have a low risk of bias, seven had a moderate risk of bias, one had a serious risk of bias, and two had some concerns. CONCLUSIONS: Our findings suggest that RME results in variable soft tissue facial changes over time. The findings resulted statistically significant for alar width, alar base width, and nasolabial angle, showing changes in the facial soft tissues after non-surgical rapid maxillary expansion, especially in the nasal area. These results, which are directly related to the anatomical effects of the rapid maxillary expansion, need careful consideration by clinicians as the skeletal and the consequent soft tissue changes may be influenced by different factors, i.e. patient age, appliance activation and follow-up duration. PROSPERO reference number: CRD42024505738.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.020 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.008 |
| Bibliometrics | 0.005 | 0.005 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".