Impact of Bone-Borne and Miniscrew-Assisted Rapid Palatal Expansion on Airway Dimensions and Postexpansion Stability: Evidence From Cone-Beam CT Studies

This review aimed to synthesize cone-beam CT (CBCT) evidence on changes in upper airway dimensions and postexpansion stability following miniscrew-assisted rapid palatal expansion (MARPE) and other bone-borne expanders. A systematic review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses 2020 guidelines. PubMed/MEDLINE, Cochrane Library, ScienceDirect, Semantic Scholar, and Google Scholar were searched for English-language human clinical studies published from 2010 to August 2, 2025. Eligible designs included randomized and non-randomized trials and prospective/retrospective cohorts reporting CBCT-derived linear or volumetric nasal and upper airway outcomes with at least five months of follow-up, using pre-post comparisons and/or comparisons with conventional expanders or untreated controls. Two reviewers independently screened studies, extracted data, assessed risk of bias, and evaluated certainty of evidence. Owing to heterogeneity in appliance designs, airway segment definitions, and follow-up schedules, a meta-analysis was not performed, and findings were narratively synthesized. In total, 17 studies (14 unique datasets) involving 12-102 participants per study and ages ranging from 8 to 33 years were included. Most studies demonstrated short- to mid-term increases in nasal cavity width/volume and nasopharyngeal dimensions after MARPE-type expansion, suggesting predominant anterior airway effects. Changes in the oropharyngeal region were inconsistent, with some studies showing enlargement and others showing no measurable difference. Long-term follow-up (≥12 months) generally indicated maintenance of skeletal and airway gains, though partial relapse was reported in some parameters; skeletal relapse tended to be smaller than dental relapse. Overall certainty of evidence for airway outcomes was low to very low. MARPE and related bone-borne expanders may increase nasal and nasopharyngeal airway dimensions and offer relatively stable transverse skeletal widening, but the predictability and clinical durability of airway benefits remain uncertain. Higher quality studies with standardized CBCT protocols and added functional airway assessments are required to confirm long-term clinical relevance.