Oropharyngeal dimensional changes following maxillary expansion with two different appliances: a CBCT study

• Author / Creator

  Capenakas, Silvia Patricio Gianoni

• Maxillary expansion is used to correct maxillary deficiencies, the most common technique is the Rapid Maxillary Expansion. Although there are several other treatment types depending on age such as surgery or archwire; maxillary expansion, have been related to the increase of the upper airway volume and minimal cross-sectional area (MCA). However, contradictory results regarding the measured changes in the oropharyngeal portion of upper airway have led to uncer-tainty about the real effect of maxillary expansion on the oropharynx dimensions.
  Moreover, there is no published research regarding oropharyngeal dimensional changes after the application of Damon philosophical treatment approach. Following the claim from Damon proponents that the therapeutic effect after its use in the constricted maxilla is a broader dental arch due to alveolar bone remodeling. We speculate if the oropharyngeal volume and MCA could also be increased. Therefore, the main objective of this study is to compare the vol-ume and MCA changes in the oropharyngeal space following maxillary expansion using the Damon system versus Hyrax appliances, assessed through CBCT imaging.
  A retrospective analysis of data from a randomized parallel clinical controlled trial with an allocation ratio of 1:1 was conducted. Patients between 11 to 17 years old, with maxillary transverse discrepancies in need of maxillary expansion, were included and randomly allocated into one of two treatment groups, Hyrax or Damon, in the orthodontic clinic at the University of Alberta, Edmonton Canada. Patients underwent CBCT imaging at three time-points: T1- before treatment and after clinical evaluation, to further evaluate and assist the clinicians on the diag-nosis on dental and craniofacial orthodontic discrepancies; T2- at 6 months, and T3- after com-pletion of all orthodontic treatment. The CBCT data was assessed through Invivo Software (Anatomage, San Jose, California, US) and Dolphin Software (Dolphin Imaging & Management Solutions, Chatsworth, California US). Reliability of measurements was done to certify the re-producibility of the research. In addition, a qualitative assessment of breathing function was done using the NOSE questionnaire modified from The NOSE Scale 2003 developed by the American Academy of Otolaryngology-Head and Neck Surgery Foundation. Repeated measures multivariate analysis of variance (MANOVA) and Bonferroni post-hoc tests were used to ana-lyse the differences between the treatment groups at each time-point and each software. A paired-sample t-test was applied to verify whether or not the changes were statistically signifi-cant. All the statistical analysis was made at a 5% significance level (95% CI) using IBM SPSS statistics 25 version (SPSS Inc, Chicago, IL).
  A reliability assessment was done evaluating intra-reliability and inter-reliability with a second examiner. All results ranged above the excellent range of 90%. Our study showed a sta-tistically significant increase in the oropharyngeal volume after 6 months maxillary expansion (T2), and after the completion of treatment (T3) when the oropharyngeal volume was evaluated in the Hyrax group with both software. Also, results showed a statistically significant increase in the MCA in the Hyrax group when evaluated with Dolphin software. The Invivo and Dolphin software showed they are statistically different when oropharyngeal dimensions were compared. Our results on the NOSE questionnaire showed no statistically significant improvement in breathing between time-points in both treatment groups. Future research should focus on airway function to correlate the dimensional changes to airflow and respiratory capacity function after maxillary expansion treatment. As well, the qualitative analysis with patient’s feedback by questionnaire could elucidate the patient’s breathing improvement after orthodontic therapy.

• Subjects / Keywords

  • maxillary expansion
  • Oropharynx
  • upper airway
  • CBCT

• Graduation date

  Fall 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-d6ng-xq25

• License

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