Three-dimensional analyses of palatal morphology and its relation to upper airway area in obstructive sleep apnea

Abstract

Objective: To evaluate the relationship between palatal morphology and pharyngeal airway morphology in patients who have obstructive sleep apnea (OSA) and compare with a nonsnoring and nonapneic control group.

Materials and methods: Three-dimensional maxillary dental cast measurements from 25 OSA patients (6 women, 19 men) with a mean age of 41.5 (4.8) years, and 25 control group participants (14 women, 11 men) without any symptom of OSA with a mean age of 38.3 (3.7) were correlated with an analysis of pharyngeal area evaluated with lateral cephalograms. Intermolar and intercanine widths and palatal volumes were calculated on the dental casts, and the upper airway area measurements were performed on lateral cephalograms.

Results: OSA patients had smaller oropharyngeal volume and upper airway when compared with controls (P < .001). Palatal area measurements were significantly smaller in OSA (P < .001). OSA patients had significantly narrower maxilla with smaller intermolar and intercanine widths (P < .001). A positive correlation was found between the palatal morphology and pharyngeal dimensions.

Conclusions: A significant correlation exists between palatal morphology and pharyngeal airway.

Keywords: 3D volumetric analysis; Obstructive sleep apnea; Palatal volume; Upper airway.

Figure 1.

Diagrammatic representation of landmarks and tracings of the nasopharynx, oropharynx, and soft palate. Ad1 indicates upper point of adenoid tissue; PNS, posterior nasal spine; Epg, tip of epiglottis; Xi, geographic center of ramus; PTV, pterygoid vertical plane; FH, Frankfort horizontal plane; soft palate area, soft palate that starts and ends at PNS; nasopharynx, area outlined between the line passing through Ad1 point to the PNS, extension of the palatal plane to posterior pharyngeal wall and posterior pharyngeal wall; oropharynx, area outlined by the inferior border of nasopharynx, the posterior and inferior surface of soft palate, the line parallel to the FH plane through point Epg.

Figure 2.

The intercanine (IC) and intermolar (IM) distances on the digital models.

Figure 3.

Palatal volume is defined as shown (a–d). Gingival plane was constructed by connecting the line of the dento-gingival junction of all erupted teeth. The distal plane is constructed perpendicular to the dento-gingival plane passing from two most distal points corresponding to the distal surface of the second molar teeth. The palatal vault is the cranial border of the three-dimensional image. (a) The palatal aspect. (b) The overall volumetric image distracted from the dental model image. (c) The facial aspect. (d) The posterior aspect of the palatal volumetric analysis.