Non-Cochrane · intervention · PM41897108
Transverse Maxillary Correction: Leaf Expander vs. Rapid Maxillary Expansion Appliances-A Systematic Review and Meta-Analysis.
Caramaschi Elena, Verdecchia Alessio, Ledda Maurizio, et al. · Children (Basel, Switzerland) · 2026 · PubMed · doi:10.3390/children13030396
Findings
Population Skeletally immature patients with maxillary transverse deficiency
4 findings
| Slow maxillary expansion (SME) with spring-based Leaf Expander | Rapid maxillary expansion (RME) with conventional Hyrax- or Haas-type expander | Inter-first permanent molar distance (IFPM) transverse change Change from baseline (T0) to post-treatment (T1), at completion of active expansion · Orthodontic clinics, Italy (multicenter RCTs) | SMD -0.17 [-0.56, 0.21] Very low Downgraded: risk of bias, imprecision, inconsistency, indirectness 3 studies |
| Slow maxillary expansion (SME) with spring-based Leaf Expander | Rapid maxillary expansion (RME) with conventional Hyrax- or Haas-type expander | Inter-second deciduous molar distance (ISDM) transverse change Change from baseline (T0) to post-treatment (T1), at completion of active expansion · Orthodontic clinics, Italy (multicenter RCTs) | SMD 0.19 [-1.47, 1.86] Very low Downgraded: risk of bias, imprecision, inconsistency 2 studies |
| Slow maxillary expansion (SME) with spring-based Leaf Expander | Rapid maxillary expansion (RME) with conventional Hyrax- or Haas-type expander | Inter-canine distance (IDC) transverse change Change from baseline (T0) to post-treatment (T1), at completion of active expansion · Orthodontic clinics, Italy (multicenter RCTs) | SMD 0.13 [-1.24, 1.50] Low Downgraded: imprecision, inconsistency 2 studies |
| Slow maxillary expansion (SME) with spring-based Leaf Expander | Rapid maxillary expansion (RME) with conventional Hyrax- or Haas-type expander | Basal maxillary width (BMW) transverse change Change from baseline (T0) to post-treatment (T1), at completion of active expansion · Orthodontic clinics, Italy (multicenter RCTs) | SMD -0.34 [-0.77, 0.08] Very low Downgraded: risk of bias, imprecision, inconsistency, indirectness 2 studies |
Included primary studies 8
Open in Studies| Study | Year | Also included by | Outcomes it informs here | Trial data |
|---|---|---|---|---|
| Abate 2024 Three-dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni-ti leaf springs expander and rapid… PMID:39244736 | 2025 | this review only | not stated | not extracted yet |
| Abate 2025 Three‐dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni‐ti leaf springs expander and rapid… DOI:10.1111/ocr.12849 | 2024 | this review only | Inter-canine distance (IDC) transverse change; Inter-second deciduous molar distance (ISDM) transverse change; Inter-first permanent molar distance (IFPM) transverse change | not extracted yet |
| Paoloni 2022 Comparison of the dento-skeletal effects produced by Leaf expander versus rapid maxillary expander in prepubertal patients: a two-center… DOI:10.1093/ejo/cjab035 | 2021 | this review only | Inter-canine distance (IDC) transverse change; Inter-first permanent molar distance (IFPM) transverse change; Basal maxillary width (BMW) transverse change | not extracted yet |
| Paoloni 2022 Comparison of the dento-skeletal effects produced by Leaf expander versus rapid maxillary expander in prepubertal patients: a two-center… PMID:34114608 | 2022 | this review only | not stated | not extracted yet |
| Serafin 2022 CBCT Analysis of Dento-Skeletal Changes after Rapid versus Slow Maxillary Expansion on Deciduous Teeth: A Randomized Clinical Trial DOI:10.3390/jcm11164887 | 2022 | this review only | Inter-second deciduous molar distance (ISDM) transverse change; Inter-first permanent molar distance (IFPM) transverse change; Basal maxillary width (BMW) transverse change | not extracted yet |
| Serafin 2022 CBCT Analysis of Dento-Skeletal Changes after Rapid versus Slow Maxillary Expansion on Deciduous Teeth: A Randomized Clinical Trial. PMID:36013125 | 2022 | this review only | not stated | not extracted yet |
| Ugolini 2025 DOI:10.23804/ejpd.2024.2208 | NR | this review only | not stated | not extracted yet |
| Ugolini 2025 Effects On Palatal Surface Area In Mixed Dentition Patients Treated With Leaf Expander And Rapid Palatal Expander, Compared To Untreated… PMID:39360909 | 2025 | this review only | not stated | not extracted yet |
Review question
| Element | Planned (methods) | Found (results) |
|---|---|---|
| Population | Skeletally immature patients with maxillary transverse deficiency | Skeletally immature patients with transverse deficiency, mean age about 7.7 to 9 years (n=301 across 4 RCTs) |
| Intervention | Slow maxillary expansion with spring-based Leaf Expander | Leaf Expander 450 g or 900 g anchored on deciduous second molars (n=143) |
| Comparison | Rapid maxillary expansion with conventional Hyrax- or Haas-type expanders | Hyrax-type rapid maxillary expander (n=141); one trial also had untreated controls (n=17) |
| Outcomes | Primary: transverse maxillary change (skeletal and dental widths); secondary: dentoalveolar effects (molar tipping, distorotation) | Inter-canine, inter-second deciduous molar, inter-first permanent molar and basal maxillary width; palatal surface; molar distorotation and tipping |
| Study designs | RCTs | RCTs (n=4), 3 in quantitative synthesis |
| Timing | Not specified | Active expansion phase; follow-up up to about 1 year |
AMSTAR 2 items
Two independent extractors rated each item. Their ratings are shown side by side because they have not been reconciled yet. The overall rating follows Shea et al. 2017: one critical flaw gives Low, more than one gives Critically Low.
| Item | Extractor A | Extractor B | Agree |
|---|---|---|---|
| 1Research question includes PICO components | Yes | Yes | yes |
| 2Protocol established before the reviewcritical | Partial Yes | Partial Yes | yes |
| 3Choice of study designs explained | No | No | yes |
| 4Comprehensive literature searchcritical | Partial Yes | Partial Yes | yes |
| 5Study selection in duplicate | Yes | Yes | yes |
| 6Data extraction in duplicate | Yes | Yes | yes |
| 7List of excluded studies with reasonscritical | No | No | yes |
| 8Included studies described in detail | Yes | Yes | yes |
| 9Risk of bias assessed satisfactorilycritical | RCT: Yes · NRSI: N/A | NRSI: N/A · RCT: Yes | no |
| 10Funding of included studies reported | No | No | yes |
| 11Appropriate meta-analysis methodscritical | RCT: No · NRSI: N/A | NRSI: N/A · RCT: No | no |
| 12Impact of risk of bias on the pooled results | No | No | yes |
| 13Risk of bias accounted for in interpretationcritical | Yes | Yes | yes |
| 14Heterogeneity explained | Yes | Yes | yes |
| 15Publication bias investigatedcritical | Yes | Yes | yes |
| 16Conflicts of interest reported | Yes | Yes | yes |
| Overall | Critically Low | Critically Low | yes |