Skeletal and airway stability after mandibular setback in patients with mandibular prognathism: A systematic review

Abstract

Aim: To perform a systematic review to answer the clinical question "What are the longitudinal skeletal and airway changes after mandibular setback orthognathic procedures?"

Materials and methods: A systematic search including computer search of different databases with specific keywords, manual search through three international journals and reference list search was performed. Articles that were reporting the skeletal and airway changes after mandibular setback orthognathic procedures were evaluated with five predetermined criteria.

Results: Six articles with a total of 217 patients entered the final review. All were rated to be of moderate bias risk. Four studies evaluated the skeletal and airway changes using two-dimensional (lateral) cephalometric radiographic imaging, whereas the other two studies used three-dimensional imaging with cone-beam computed tomography. In the two-dimensional studies, skeletal relapses from T0 (immediate postoperative) to T1 (postoperative 1-6 months) ranged from -2.14 mm to 0.30 mm, whereas skeletal relapses from T1 to T2 (postoperative 1 year) ranged from -0.90 mm to 1.23 mm. In the three-dimensional studies, skeletal relapse from T1 to T2 ranged from -0.26 mm to 1.53 mm. All included studies reported that there were no significant skeletal relapses after mandibular setback procedures. Regarding airway changes, airway changes from preoperative to T0/T1 ranged from -0.30 mm to -2.32 mm in the two-dimensional studies. Airway changes from T0 to T1 ranged from -0.70 mm to -1.63 mm, whereas airway changes from T1 to T2 ranged from 0.11 mm to 0.60 mm, respectively.

Conclusions: This systematic review showed there was insignificant skeletal relapse after mandibular setback orthognathic procedures. It was noted a small increase of the airway over the first post-operative year in studies using 2-dimensional radiography. However, such finding was not consistent in studies using 3-dimensional imaging with volumetric analysis of the airway changes.

Keywords: Airway changes; CIII malocclusion; Hyoid bone; Mandibular setback; Orthognathic procedures; Radiographic imaging.

Fig. 1

PRISMA chart of the article selection process.

Fig. 2

Postoperative two-dimensional skeletal changes (mm) between T1 (1–6 months) and T2 (12 months) compared to preoperative measurement. (A negative value indicates posterior movement.)

Fig. 3

Postoperative two-dimensional airway changes (mm) between T1 (1–6 months) and T2 (12 months) compared to preoperative measurement in two-dimensional measurements. (A negative value indicates posterior movement.)