Orthopedic Treatment for Class II Malocclusion with Functional Appliances and Its Effect on Upper Airways: A Systematic Review with Meta-Analysis

Abstract

Aim of this systematic review was to assess the effects of orthopedic treatment for Class II malocclusion with Functional Appliances (FAs) on the dimensions of the upper airways. Eight databases were searched up to October 2020 for randomized or nonrandomized clinical studies on FA treatment of Class II patients with untreated control groups. After duplicate study selection, data extraction, and risk of bias assessment according to Cochrane guidelines, random effects meta-analyses of mean differences (MDs) and their 95% confidence intervals (CIs) were performed, followed by subgroup/meta-regression analyses and assessment of the quality of evidence. A total of 20 nonrandomized clinical studies (4 prospective/16 retrospective) including 969 patients (47.9% male; mean age 10.9 years) were identified. Orthopedic treatment with FAs was associated with increased oropharynx volume (MD = 2356.14 mm3; 95% CI = 1276.36 to 3435.92 mm3; p < 0.001) compared to natural growth. Additionally, significant increases in nasopharynx volume, minimal constricted axial area of pharyngeal airway, and airway were seen, while removable FAs showed considerably greater effects than fixed FAs (p = 0.04). Finally, patient age and treatment duration had a significant influence in the effect of FAs on airways, as had baseline matching and sample size adequacy. Clinical evidence on orthopedic Class II treatment with FAs is associated with increased upper airway dimensions. However, the quality of evidence is very low due to methodological issues of existing studies, while the clinical relevance of increases in airway dimensions remains unclear.

Changing patterns in reporting and sharing of review data in systematic reviews with meta-analysis of the effects of interventions: a meta-research study

“…[45]), excluded studies at each stage of screening (e.g. [46]) and complete data for all meta-analyses (e.g. [47]).…”

Changing patterns in reporting and sharing of review data in systematic reviews with meta-analysis of the effects of interventions: cross sectional meta-research study

“…Web based supplementary files and public repositories enable authors to share data and materials necessary to validate the review process while keeping the main article concise and relevant to lay readers. 10 For example, authors can outline in a separate file all search strategies specific to databases (eg, Saeteaw et al 45 ), excluded studies at each stage of screening (eg, Bidjan et al 46 ), and complete data for all meta-analyses (eg, Hill et al 47 ). Data sharing via supplementary files or public repositories is an effective tool to improve reproducibility of systematic reviews and should be made a standard practice.…”

Short-term Volumetric and Minimal Area Changes in the Pharyngeal Airway After Use of a Fixed Functional Appliance: A Three-dimensional CBCT Investigation

“…4 Several treatment modalities such as extractions, headgear, and Class II functional appliances can affect upper airway dimensions. 7,8 Previous studies 5,[7][8][9][10] used cephalometric radiographs to assess the effects of different functional appliances (fixed and removable) on pharyngeal dimensions in growing skeletal Class II patients. However, the advent of cone beam computed tomography (CBCT) imaging has raised questions about the accuracy and usefulness of 2D cephalometrics compared with 3D CBCT imaging.…”