Pharyngeal airway space and frontal and sphenoid sinus changes after maxillomandibular advancement with counterclockwise rotation for Class II anterior open bite malocclusions

Abstract

Objectives: The purpose of this study was to cephalometrically evaluate the pharyngeal airway space and frontal and sphenoid sinus changes after maxillomandibular advancement counterclockwise rotation for class II anterior open bite malocclusion.

Methods: The study included 49 patients (98 lateral teleradiographs; 36 females and 13 males) who were analysed in the pre-operative (1 week before surgery) and post-operative (6 months after surgery) periods. In each lateral teleradiography, the dimensions of the inferior and superior pharyngeal airway space, TB-PhW1 [the point between the posterior aspect of the tongue to the dorsal pharyngeal wall (oropharynx) (TB) and the point on the dorsal pharyngeal wall closest to TB (PhW1)] and UP-PhW2 [and the point between the posterior aspect of the soft palate to the dorsal pharyngeal wall (nasopharynx) (UP) (PhW2)] measurements were evaluated, as well as the dimensions of the frontal and sphenoid sinuses. The differences between the two operative times were evaluated by Student's t-test.

Results: All measurements showed excellent reproducibility for the intraclass correlation coefficient (ICC > 0.9; p < 0.0001). There was an increase in the measurements TB-PhW1 and UP-PhW2 and a decrease in the dimensions of the frontal and sphenoid sinuses after orthognathic surgery.

Conclusions: The morphology of the superior and inferior pharyngeal airway space and frontal and sphenoid sinuses changes after 6 months of maxillomandibular advancement counterclockwise rotation for class II anterior open bite malocclusion.

Figure 1

Diagram of lateral cephalometric image with all the relevant anatomic landmarks labeled. A, deepest point of the outline of the pre-maxilla located between the anterior nasal spine and porion; B, deepest point in the most internal part of the contour of the mandible in the region between the incisors and Me; Go, gonion; Me, menton; N, nasion; PhW1, point on the dorsal pharyngeal wall closest to TB; PhW2, the point on dorsal pharyngeal wall closest to UP; S, sella; TB, point between posterior aspect of tongue to dorsal pharyngeal wall (oropharynx); UP, point between posterior aspect of soft palate to dorsal pharyngeal wall (nasopharynx)

Figure 2

Outline of the periphery of the frontal sinus on lateral cephalograms according to criteria of Ertürk. N, nasion point; S, sella point; Sh, most superior point of the frontal sinus contour; SI, most inferior point of the frontal sinus contour

Figure 3

Outline of the periphery of the sphenoid sinus on lateral cephalograms according to criteria of Ferreira and Oliveira

Figure 4

Means (± standard deviation) of the measurement of the point between posterior aspect of tongue to dorsal pharyngeal wall (oropharynx) (TB) and point on the dorsal pharyngeal wall closest to TB (PhW1) and the measurement of UP and the point on dorsal pharyngeal wall closest to the point between the posterior aspect of soft palate to dorsal pharyngeal wall (nasopharynx) (UP) (PhW2) at the two operative periods (t-test)

Figure 5

Means (± standard deviation) of measurements of the angle formed by sella point (S), nasion point (N) and point A, the angle formed by S, N and point B, and gonial at the two operative periods (t-test). Point A, deepest point of the outline of the pre-maxilla located between the anterior nasal spine and porion; point B, deepest point in the most internal part of the contour of the mandible in the region between the incisors and menton

Figure 6

Means (± standard deviation) of the measurements of anterior nasal spine (ANS)-menton (Me), Me-nasion (N) and sella (S)-gonion (Go) at the two operative periods (t-test)

Figure 7

Means (± standard deviation) of the means of the frontal and sphenoid sinuses before and after surgery (t-test)