Avaliação cefalométrica do espaço aéreo posterior em pacientes com oclusão Classe II submetidos à cirurgia ortognática

Effects of surgical mandibular advancement on the upper airways of adult class II patients: A systematic review with meta-analysis

AIM

To systematically review the effects of surgical mandibular advancement (SMA) regarding changes of the upper airways in adult patients with skeletal Class II malocclusion.

MATERIALS AND METHODS

Five electronic databases were searched up to April 2020. Human studies focusing on the morphology and dimension of the upper airways after SMA were included. 'Quality assessment for Before-After (Pre-Post) Studies' was used to assess the risk of bias of the individual studies. Standard mean differences (SMD) with 95% confidence intervals (CI) were calculated for random effect model meta-analysis. The certainty of evidence was assessed using the GRADE tool.

RESULTS

Twenty cohort studies of only treated patients without control group were eligible for qualitative synthesis, of which 17 were used for quantitative synthesis. Very low certainty of evidence indicated that SMA resulted in significant increase of the volume and of the smallest cross-sectional area (SMC) of the nasopharynx (volume SMD: 1.43, CI: 0.62, 2.24, P = .001, I²  = 87.8%; SMC SMD: 1.53, CI: 0.59, 2.47, P = .001, I²  = 90.5%) and oropharynx (volume SMD: 1.36, CI: 0.37,2.35, P = .007, I²  = 92.1%; SMC SMD: 1.21, CI: 0.11,2.32, P = .032, I²  = 93.1%). Significant augmentation of the distances between the posterior pharynx wall and the uvala (SMD: 0.73, CI: 0.46,0.98, P < .001, I²  = 72.7%), the posterior border of the tongue (SMD: 0.52, CI: 0.21,0.84, P = .001; I² : 60.5%), the gonion (SMD: 1.24, CI: 0.56,1.91, P < .001; I²  = 88.8%) and the epiglottis (SMD: 0.40, CI: 0.06,0.74, P = .033; I²  = 84.8%) were observed.

CONCLUSIONS

Weak evidence suggests enlargement of the upper airways of adult Class II subjects following SMA, with major increases in the oropharynx.

Effects of chin advancement surgery in hyoid bone and tongue positions and in the dimension of the oropharynx

INTRODUCTION

Advancement genioplasty has been increasingly indicated for the correction of anterior mandibular deficiency as it balances the patient's profile and generates functional changes.

OBJECTIVE

Thus, the aim of this study was to assess the effects of advancement genioplasty in the oropharyngeal size and in the position of the hyoid bone and tongue.

METHODS

The sample comprised 22 lateral cephalometric radiographs of 11 individuals who had undergone advancement genioplasty alone. Eleven of these radiographs depicted the immediate preoperative period (T0) and the other 11 the postoperative period after at least four months (T1). The radiographs were scanned and exported to the Radiocef Studio 2.0® software (Radio Memory Ltda., Belo Horizonte, MG, Brazil). The landmarks were then identified and automatically measured by the program.

RESULTS

The results showed statistically significant differences between the horizontal position of the hyoid bone and tongue and in the oropharyngeal size. The hyoid bone and tongue were repositioned anteriorly after surgery (p = 0.01), thereby increasing the dimension of the oropharyngeal airspace (p = 0.01).

CONCLUSIONS

The oropharyngeal dimension increased as the tongue base and hyoid bone were repositioned more anteriorly.

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

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.