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Original Article

Changes in upper airway width associated with Class II treatments (headgear vs activator) and different growth patterns
Arnim Godta; Bernd Koosa; Hanno Hagenb; Gernot Gozc ¨
ABSTRACT Objective: To investigate the upper airways for anteroposterior width against different growth patterns and for alterations during various Class II treatments. Materials and Methods:Cephalograms from three treatment groups (headgear, activator, and bite-jumping appliance) were evaluated by a single investigator at baseline and at the end of orthodontic treatment. Cephalograms were used to determine upper airway width at different levels in the anteroposterior plane. Patients in the headgear group were additionally divided into six subsets on the basis of y-axis values to assess theinfluence of different growth patterns. Results: Small increases in pharyngeal width were noted at all vertical level segments, both at baseline and during orthodontic treatments. No significant differences in these small increases were noted across various treatment modalities and growth patterns. Conclusion: Upper airway changes did not significantly vary with the different treatment modalitiesinvestigated in the present study. Nevertheless, reductions in pharyngeal width potentially triggering or exacerbating obstructive sleep apnea syndrome (OSAS) are always possible in the headgear phase. (Angle Orthod. 0000;00:000–000.) KEY WORDS: Headgear; Growth pattern; Cephalometric analysis; Posterior airway space

INTRODUCTION Along with exogenous factors such as alcohol or sedatives, theoccurrence of the obstructive sleep apnea syndrome (OSAS) is favored by anatomic and pathologic alterations in the area of the upper airways.1 Thanks to its three-dimensional representation of anatomic structures, computed tomography (CT) is considered an excellent diagnostic tool to evaluate the width of the upper airways (along with magnetic resonance imaging). This width has been shown tocorrelate with the severity of OSAS.2 As far back as 1986, Riley et al.3 demonstrated a correlation between assessments based on CT scans and assessments based on cephalograms, which led
Assistant Professor, Department of Orthodontics, EberhardKarls-Universitat, Tubingen, Germany. ¨ ¨ b Dental student, Department of Orthodontics, EberhardKarls-Universitat, Tubingen, Germany. ¨ ¨ c Professor andDepartment Chair, Department of Orthodontics, Eberhard-Karls-Universitat, Tubingen, Germany. ¨ ¨ Corresponding author: Dr Arnim Godt, University Hospital of Tubingen, Department of Orthodontics, Osianderstrasse 2-8, ¨ 72076 Tubingen, Germany ¨ (e-mail: arnim.godt@med.uni-tuebingen.de)
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Accepted: October 2010. Submitted: September 2010. Published Online: January 24, 2011 G 2011 by The EH AngleEducation and Research Foundation, Inc.
DOI: 10.2319/090710-525.1 1

them to conclude that the latter was appropriate for basic diagnostic purposes. More recently, some authors reported differences in anteroposterior distances in the pharyngeal space between patients with and without demonstrated OSAS at different vertical levels.4–11 Cephalography could be used to quantify successful treatmentsfor OSAS by measures such as surgical advancement of the jaw (especially the mandible),6,12–16 surgical advancement of the geniohyoid muscle attachment,15,17,18 continuous positive airway pressure (cPAP) treatment,10 adenotomy,19 or advancement appliances.5 The limitations of analysis made themselves felt in the presence of specific muscle or hormonal diseases,20,21 or when attempts were made topredict OSAS on the basis of these values.22 However, patients with OSAS frequently showed other characteristics in connection with pharyngeal narrowness, including a retrognathic jaw position, dolichocephalic architecture of the facial skull, and a caudal position of the hyoid bone,1 such that the width of the pharyngeal space became relevant to a number of different orthodontic issues and...