Evaluation of the effects of different rapid maxillary expansion appliances on airway by acoustic rhinometry: A randomized clinical trial

Objective: The purpose of this 3-arm parallel trial was to compare the effects of tooth tissue-borne (TTB), tooth borne (TB) and bone-borne (BB) rapid maxillary expansion (RME) appliances on nasal airway with acoustic rhinometry (AR).Setting and sample population: Forty-six 12-to 14-year-old patients with narrow maxilla were randomly allocated into 3 study groups accordingly the type of expander: TTB, TB and BB. The participants were recruited from the Department of Orthodontics, Izmir Katip Celebi University.Materials and methods: All patients had RME with an initial activation of two-quarter turns a day (0.5 mm) for an average of 8 days followed by 1 quarter turns per day for an average of 10 days. Disguised group allocation using opaque sealed envelopes was made with a computer-generated randomization program. The primary outcome was changes on the minimal nasal cross-sectional area (MCA). Secondary outcome included the assessment of nasal cavity volume. AR measurements were obtained at baseline (T0), immediately after the expansion (T1), and at 3 months-follow-up (T2). One-way analysis of variance (ANOVA) and Bonferroni test were used for intergroup comparison and two-way ANOVA was used for intra-group evaluation.Results: There were significant increases in MCA 1, 2 and nasal Vol in all groups after the treatment (95% [CI], P < 0.05) whereas in inter-group comparisons; MCA 1, 2 and nasal Vol, the changes were found to be similar (95% [CI], P > 0.05).Harms: No serious harm was observed except for mild gingivitis due to plaque accumulation.Conclusions: RME treatment increased minimal nasal cross-sectional areas and nasal volume irrespective of appliance design.Trial registration: This trial was registered at Clinicaltrials.gov (Identifier NCT04529057).Protocol: The protocol was not published.Funding: This trial was financed by Izmir Katip Celebi University, Scientific Research Projects Unit [grant number 2016-TDR-SABE-0024].