Effects Of Extraction Versus Non-Extraction Treatment On Oropharyngeal Airway Volume

Original Article

Effects of extraction versus non-extraction treatment on oropharyngeal airway volume
Manish Valiathana; Hakan Elb; Mark G. Hansc; Martin J. Palomod
ABSTRACT Objective: To compare the effects of extraction vs nonextraction orthodontic treatments on oropharyngeal airway volume. Materials and Methods: An existing patient database was screened for pretreatment (T0) andposttreatment (T1) cone beam computed tomography (CBCT) scans and complete medical histories. Twenty patients treated with removal of four premolars (ExtG) and 20 controls (NExtG), were matched for age, gender, ethnicity, height, weight, body mass index, and oropharyngeal (OP) volumes, among other variables. Constructed lateral cephalograms (three skeletal and four dental variables) and OP volumes weremeasured at T0 and T1 using Dolphin Imaging 11.0. Independent sample t-tests were used to compare the groups at T0 and the outcome variables at T1. Paired sample t-tests were used to compare the mean changes from T0 to T1. Statistical significance was set at P # .05. Results: Changes from T0 to T1 were found to be significant in both groups for CoA, CoGn, U1FH, and IMPA. In the ExtG alone, U1-Na Perpand L1-Na Perp were also significantly different from T0 to T1. Despite the observed differences, no significant differences were found at the end of treatment between the mean OP volumes for either group (12,675.6 6 4483.6 for ExtG; 12,002.7 6 2857.0 for NExtG, P . .05). Similarly, the mean changes in OP volume (1082.6 mm3 and 1701.1 mm3 for ExtG and NExtG, respectively) and increase in meanminimal constricted axial areas (17.4 mm2 and 1.9 mm2 for ExtG and NExtG, respectively, P . .05) from T0 to T1 were not significant for the two groups. Conclusion: Extraction of four premolars with retraction of incisors does not affect OP airway volume. (Angle Orthod. 2010;80:1068–1074.) KEY WORDS: Airway; Extraction; Outcomes; CBCT

INTRODUCTION Traditional radiographic cephalometrics, magneticresonance imaging (MRI), and computed tomography
a Assistant Professor of Orthodontics, Case Western Reserve University, School of Dental Medicine, Cleveland, Ohio. b Research Scholar, Hacettepe University, School of Dental Medicine, Ankara, Turkey. c Professor and Chair, Department of Orthodontics, Associate Dean for Graduate Studies, Case Western Reserve University, School of Dental Medicine,Cleveland, Ohio. d Associate Professor and Program Director, Department of Orthodontics, Case Western Reserve University, Cleveland, Ohio. Corresponding author: Manish Valiathan, DDS, MSD, Assistant Professor of Orthodontics, School of Dental Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4905 (e-mail: manish.valiathan@case.edu)

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Accepted: May 2010.Submitted: January 2010. 2010 by The EH Angle Education and Research Foundation, Inc.
1068

(CT) are widely used static imaging modalities for the assessment of airway anatomy and volume.1 The ability to perform precise measurements of various cross-sectional areas, three-dimensional (3D) reconstructions, and volumetric measurements of the upper airway are some of the advantages of CT technology whencompared with cephalometric techniques. Following the introduction of cone beam CT (CBCT), the main disadvantages of conventional CT devices, such as high radiation dose and longer exposure times, were eliminated.2,3 Although MRIs operate without the need for ionizing radiation, an MRI requires significantly longer operating time that results in decreased airway image quality due to motionartifacts.4 In other words, CBCTs have led to a better understanding of upper airway anatomy and physiology.5 The upper airway has always been an area of interest because the oropharyngeal and nasopharyngeal structures play important roles in the growth and development of the craniofacial and orodental comDOI: 10.2319/010810-19.1

Angle Orthodontist, Vol 80, No 6, 2010

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