Upper Airways Cephalometric Measures Compared to Skeletal Class and Divergence

Study Overview
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Brief Summary
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The aim of the present study is to investigate the baseline upper airways dimensions in adult patients belonging to all skeletal classes

Detailed Description
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Lateral cephalometric radiographs of adult orthodontic patients referring for orthodontic consultation at the Unit of Orthodontics and Pediatric Dentistry, Section of Dentistry, Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, 27100 Pavia, Italy, will be collected for the study according to the inclusion criteria. For each lateral cephalometric radiograph, a cephalometric tracing will be performed with DeltaDent software (version 2.2.1, Outside Format, Spino d'Adda, Italy). Riedel's ANB angle [Riedel 1952] has been adopted to determine patients' skeletal class. Steiner's SN^GoGn angle [Steiner 1953] will be used to evaluate skeletal divergence. Biprotrusion will be assessed for SNA > 84° and SNB > 82°, while biretrusion for SNA < 80° and SNB < 78°. Sample size calculation was performed with soft palate length as primary outcome. Considering alpha = 0.05 and power = 95%, an expected mean value of 31.05 with a standard deviation of 4.16 was hypothesized, with an expected mean difference of 3.34 [Sprenger et al. 2017], therefore 40 patients per group were required. Statistical analysis will be conducted with R® software (version 3.1.3 R Development Core Team, R Foundation for Statistical Computing, Wein, Austria). For each cephalometric measure belonging to the three skeletal classes, descriptive statistics (mean and standard deviation) will be calculated. Appropriate statistical tests will be used to assess data normality and multiple comparisons. Linear regressions will be performed between upper airways diameters and SNA, SNB, ANB, SN^GoGn, ANSPNS^GoGn, PT, PL, sex and age.

Official Title
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A Retrospective Cephalometric Study on Upper Airways Changes Compared to Skeletal Angle Class and Divergence: a Retrospective Observational Study

Conditions
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Skeletal Malocclusion

Intervention / Treatment
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* Diagnostic Test: Cephalometric analysis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with permanent dentition Caucasian patients Patients with one lateral cephalometric digital radiograph executed in Natural Head Position (patients were asked to keep the teeth in contact and the lips relaxed). Exclusion Criteria: maxillo-facial traumas nasopharyngeal pathologies craniofacial dysmorphisms orthognatic surgery radiographs not performed in Natural Head Position unsuitable radiographs

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Skeletal Class I patients<br>Patients from this group present 0° < ANB < 4° on the cephalometric tracing. | Diagnostic Test: Cephalometric analysis<br>* Cephalometric analysis will be performed evaluating upper airways landmarks.<br>|
| Skeletal Class II patients<br>Patients from this group present ANB > 4° on the cephalometric tracing. | Diagnostic Test: Cephalometric analysis<br>* Cephalometric analysis will be performed evaluating upper airways landmarks.<br>|
| Skeletal Class III patients<br>Patients from this group present ANB < 0° on the cephalometric tracing. | Diagnostic Test: Cephalometric analysis<br>* Cephalometric analysis will be performed evaluating upper airways landmarks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| NL (nasopharynx length) | Distance between Ad1 and PNS | Baseline | 
| PD (nasopharynx depth) | Line parallel to bispinal plane and connecting PNS and the posterior margin of pharynx | Baseline | 
| SPAS (Superior Pharyngeal Airway Space) | From the half of the posterior wall of soft palate (MMP) perpendicularly to the closest point on the posterior of the posterior wall of the pharynx | Baseline | 
| MAS (Mean Airway Space) | U1-U2 distance | Baseline | 
| PAS min (Pharyngeal Airway Space minimum) | T1-T2 distance along Go-B parallel line | Baseline | 
| IAS (Inferior Airway Space) | From the superior margin of the epiglottis (Ph1) to the closest perpendicular point on the posterior wall of the pharynx | Baseline | 
| LPW (Lateral Pharyngeal Wall) | Distance between epiglottic vallecula (Va1) and the posterior wall of pharynx perpendicular to Va1 | Baseline | 
| PT | Soft palate thickness | Baseline | 
| PL | Soft palate length | Baseline | 
| MPH (Mandibular Plane - Hyoid bone) | Distance from the most anterior and superior point of the hyoid bone (H1) perpendicular to mandibular plane | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Upper airways dimensions, Skeletal Class, Skeletal Divergency