Semester

Spring

Date of Graduation

2020

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Peter Ngan

Committee Co-Chair

Bryan Weaver

Committee Member

Chris Martin

Abstract

Background and Objectives: A transverse deficiency of the maxilla is a pervasive skeletal problem that can affect almost a quarter of the primary dentition population. The interesting relationship between rapid maxillary expansion (RME) and its effects on the surrounding airway is not well described in the literature. For today’s contemporary orthodontist, there are a variety of rapid palatal expanders (RPE) and expansion protocols to prescribe for patient treatment. Of late, the miniscrew-assisted RPE (MARPE) has been receiving attention by clinicians because of its increased orthopedic effects when compared to conventional RPE while avoiding the surgical procedure needed with SARPE. As MARPE treatment becomes increasingly popular, scientific evidence regarding its effects on the upper airway is limited. The orthopedic effects of RME could extend to alleviating obstructive sleep apnea symptoms with a hypothesized change in nasal and upper pharyngeal airway. The purpose of this study is to assess the volumetric changes in the nasal and pharyngeal airway volume after MARPE treatment with the use of CBCT imaging.

Experimental Design and Methods: IRB approval was granted by West Virginia University Office of Research Integrity & Compliance (#1908679933). Twenty subjects who underwent MARPE with the maxillary skeletal expander (MSE) as part of their orthodontic treatment were retrospectively studied. CBCT scans pre-expansion and immediately post-expansion with MARPE were collected from the patient archives of West Virginia University Department of Orthodontics (Morgantown, WV) and Wuhan University Department of Orthodontics (Wuhan, China). Thirteen subjects were patients of Wuhan University and seven subjects were patients of West Virginia University. Pre- and post-expansion airway volume measurements of the nasal cavity, nasopharynx, and oropharynx were measured to assess any significant changes following MARPE expansion and the resulting volumetric change in percentage. Linear measurements of the skeletal structures surrounding the nasal cavity before and after expansion were measured to assess the pattern of expansion of the airway. Statistical analysis of paired t-test and independent sample t-test (α = 0.05) were performed.

Results: When separating the subjects into those who experienced a successful orthopedic split, there was a significant increase in nasal (14.1%) and nasopharyngeal (20.4%) airway volume post-MARPE expansion. The successful split group also saw a statistically significant increase in the linear measurement of the nasal cavity base width in the frontal plane (8%), and both the anterior and posterior widths in the transverse dimension (11% and 4.2% respectively). There were no statistically significant changes for airway volume or nasal skeletal measurements for the group who did not experience an orthopedic split.

Conclusions: The post-expansion effects of MARPE treatment include an increase in nasal cavity and nasopharyngeal volume, but no evidence that MARPE expansion can enlarge the oropharyngeal airway volume. The nasal cavity expands in a triangular pattern in both the frontal and transverse dimension following orthopedic expansion with MARPE.

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