Research Article: Effect of maxillary expansion and protraction on the oropharyngeal airway in individuals with non-syndromic cleft palate with or without cleft lip

Date Published: July 30, 2019

Publisher: Public Library of Science

Author(s): Najla Alrejaye, Jonathan Gao, David Hatcher, Snehlata Oberoi, JJ Cray.


The aim of this study was to evaluate three dimensionally the effect of the combined maxillary expansion and protraction treatment on oropharyngeal airway in children with non-syndromic cleft palate with or without cleft lip (CP/L).

CBCT data of 18 preadolescent individuals (ages, 8.4 ± 1.7 years) with CP/L, who underwent Phase I orthodontic maxillary expansion with protraction, were compared before and after treatment. The average length of treatment was 24.1± 7.6 months. The airway volume and minimal cross-sectional area (MCA) were determined using 3DMD Vultus imaging software with cross-sectional areas calculated for each 2-mm over the entire length of the airway. A control group of 8 preadolescent individuals (ages, 8.7 ± 2.6 years) with CP/L was used for comparison.

There was a statistically significant increase in pharyngeal airway volume after phase I orthodontic treatment in both groups, however, there was no statistically significant change in minimal cross-sectional area in neither study nor control group.

The findings showed that maxillary expansion and protraction did not have a significant effect on increasing oropharyngeal volume and MCA in patients with CP/L.

Partial Text

Cleft palate with or without cleft lip (CP/L) is the most common congenital malformation in the craniofacial region [1,2]. Children with CP/L are known to have airway complications [3]. It has been shown through three-dimensional analysis that there is a smaller oropharyngeal height and airway volume in CP/L individuals compared with non-cleft individuals [3].

This is a retrospective study of CBCT data of preadolescent individuals with cleft palate with or without cleft lip (n = 26) who underwent Phase I orthodontics. Written informed consent was obtained for all participants and parents’ of minors of the study which was approved by the Committee on Human Research (CHR). We obtained ethics approval for our study from the ethics committee at UCSF, (CHR # 10–00564). The expansion and protraction group included 18 individuals (11 males and 7 females with CP/L; 3 cleft palate only, 5 bilateral cleft lip and palate and 10 unilateral cleft lip and palate), (ages, 8.4 ± 1.7 years). Individuals had initial and final CBCT scans taken with Care Stream (CS 9300, Carestream Health, Inc, Rochester, NY, USA) within a month of initiating and completing treatment as part of their orthodontic treatment. The scans were stored in a DICOM (Diagnostic Imaging and Communications in Medicine) format file and loaded into the 3dMDvultus software (Atlanta, GA) for 3D airway analysis.

The age distribution and observation duration between the study and the control group showed no significant differences utilizing an independent sample t-test. Fisher exact test showed no significant difference regarding the male to female distribution amongst the two groups (Table 1).

The aim of the study was to determine the effects of maxillary expansion and protraction on the oropharyngeal airway volume and MCA in non-syndromic CP/L individuals. We measured the change in volume from initial and post treatment CBCT scans of the pharyngeal airway in children with CP/L and compared the findings to a CP/L control group who had no expansion and or protraction. To the best of our knowledge, this is the first 3-D study to measure the combined effects of maxillary expansion and protraction on airway volume and smallest cross sectional area in children with CP/L. A previous recent CBCT study assessed the change in pharyngeal airway volume in CLP individuals due to maxillary protraction without expansion. Fu et al, in that study found that the pharynx significantly increased in volume in all portions after utilizing protraction [15]. In our study we hypothesized that CP/L children with expansion and protraction had larger oropharyngeal airways post treatment compared to the control group. According to our findings, 3D imaging using CBCT and 3dMDvultus is highly reliable for assessing airway volume and minimal cross-sectional area. The intraclass correlation coefficients between the double measurements were all over 0.9.




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