[Cone-beam computed tomography evaluation of upper airway change in skeletal Class III patients after orthodontic-mandibular setback surgery].

OBJECTIVE

To evaluate the short-term and long-term effects of pharyngeal airway in mandibular prognathism patients after the combined orthodontic and orthognathic treatment.

METHODS

The sample included 28 skeletal Class III patients (13 males, 15 females) who had undergone mandibular setback surgery and orthodontic treatment. Cone-beam CT was taken one week before treatment (T0), 6 months (T1) and 3 years after surgery (T2). Raw data were reconstructed into three-dimensional model. Sagittal and transversal measurements, cross sectional areas, partial and total volumes were computed.

RESULTS

Six months after surgery, oropharyngeal volume [(9 021 ± 4 263) mm³], hypopharyngeal volume [(9 236 ± 5 963) mm³] and total volume [(28 619 ± 9 854) mm³] decreased significantly (P < 0.05). Three years after surgery, only sagittal diameters [(15.9 ± 3.5) mm] and cross sectional areas [(996 ± 398) mm²] in the first cervical vertebra plane came back to the original levels (P > 0.05).

CONCLUSIONS

The pharyngeal airway space decreased after orthodontic-orthognathic therapy in the short term and it increased in some areas in the long term.