Do patients treated with Invisalign have less swelling after orthognathic surgery than those with fixed orthodontic appliances?

Introduction: Patients treated with perioperative Invisalign for orthognathic surgery may experience less postoperative swelling than those with fixed appliances because of a lack of mucosal irritation from bonded brackets and wires. The aims of this study were to (1) compare facial swelling after orthognathic surgery in subjects with Invisalign to those with fixed appliances using 3-dimensional (3D) subtraction imaging and (2) determine if the type of operation influences differences in swelling.

Methods: This is a retrospective case-control study. To be included in the case group (Invisalign), patients had to have had: (1) LeFort I and/or bilateral sagittal split osteotomies, with or without genioplasty, (2) perioperative orthodontic treatment using Invisalign, and (3) 3D photographs at postoperative timepoints 1 week (T1), 3-4 weeks (T2), and 5-7 weeks. A sex and operation-matched control group with fixed appliances (standard) was also included. The primary outcome variable was the volume of facial swelling, measured by subtraction imposition of the T1 and T2 3D images using reference images (5-7 weeks).

Results: Twenty-two subjects (36% female; mean age 20.7 ± 3.15 years) were included: Invisalign (n = 11) and standard (n = 11). For each group, 7 subjects had 1 operation (LeFort I or bilateral sagittal split osteotomies), and 4 had bimaxillary surgery ± genioplasty. At T1, the Invisalign group had significantly less swelling than the standard group (17.52 ± 10.79 cm vs 37.53 ± 14.62 cm; P <0.001). By T2, the differences were no longer significant (6.62 ± 5.19 cm for Invisalign; 5.85 ± 4.39 cm for standard, P = 0.728).

Conclusion: Subjects with Invisalign had significantly less facial swelling in the first postoperative week than those with fixed appliances.