Evaluation of the Effect of Different Rapid Maxillary Expansion Appliances on Airway by Acoustic Rhinometry
Condition: Posterior Crossbite, Upper Airway
MeSH terms: Malocclusion
Study type: Interventional

Summary: 
      Rapid maxillary expansion (RME) is an orthodontic treatment based on the principle of opening
      the midpalatal suture with the effect of orthopedic forces. The aim of this randomized
      clinical study was to evaluate and compare the effects of tooth-borne, tooth-tissue borne,
      and bone-borne rapid maxillary expanders on nasal airway by using AR. The null hypothesis was
      that there is no difference for the effect on nasal airway between the appliances.
    

Detailed description: 
      Introduction: The aim of this 3-arm parallel trial was to compare the effects of tooth-borne
      (Hyrax), tooth tissue-borne (KBME) and bone-borne (MIDME) rapid maxillary expansion (RME)
      appliances on nasal airway with acoustic rhinometry (AR).

      Methods: Fourty-six 12- to 14-years-old patients with narrow maxilla were randomly allocated
      into 3 study groups according to the type of RME appliance: tooth-borne, tooth tissue-borne
      and bone-borne. Participants were recruited from the Department of Orthodontics, Faculty of
      Dentistry, Izmir Katip Celebi University, Turkey. During the RME treatment, the same protocol
      was applied to all patients and the expansion screws were activated twice a day (0.4 mm/day).
      Computer-generated randomization was used with group allocation concealed using opaque,
      sealed envelopes. The outcome assessor was blinded; however, it was not feasible to blind
      either operator or patients. The primary outcome of this study was the correction of
      posterior crossbite. Secondary outcomes included AR assessment of nasal airway dimensions as
      nasal volume, the minimal cross-sectional area (MCA) 1 and 2. AR measurements were obtained
      before treatment (T0), after active expansion (T1), and at 3 months-follow-up (T2). One-way
      analysis of variance (ANOVA) and a Bonferroni test was used for inter-group comparison and
      two-way ANOVA was used for intra-group evalaution.
    

Intervention name(s): Rapid Maxillary Expansion Treatment
Intervention type(s): Procedure
Intervention description(s): The patients were treated with KBME, Hyrax and MIDME maxillary expansion appliances, respectively. All expansion appliances containing a Hyrax expansion screw positioned parallel to the second premolars and were used to correct the posterior crossbite. In the MIDME group, two mini-screws with a diameter of 1.6 mm and a length of 10 mm are located on the right and left sides between the roots of the 2nd premolar and 1st molar teeth with 60-70° angle. KBME and Hyrax expansion appliances were cemented with glass ionomer cement and MIDME was cemented with using the light-cured composite. Same protocol was applied to all patients during RME treatment. Expansion screws in all groups were activated by two turns a day.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: 3-arm parallel trial
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Rapid maxillary expansion, posterior crossbite, acoustic rhinometry