Evaluation of Effects of Bimaxillary Anchored Fixed Functional Appliance on Temporomandibular Joint and Maxillomandibular Complex in Late Adolescents: An MRI Study

Abstract

To evaluate and assess changes in temporomandibular joint (TMJ), dental, skeletal and soft tissue changes following bimaxillary anchored fixed functional appliance (FFA) treatment of skeletal Class II malocclusion using Magnetic Resonance Imaging. The prospective single-arm clinical trial included 15 patients (8 males, 7 females; mean age 15.71 + 1.81years) with Class II Division 1 malocclusion treated with bimaxillary anchored Forsus FRD. Four miniplates were placed bilaterally in maxilla and mandible. Then Forsus FRD L pin module was attached to miniplates without levelling of the arches. Pre-treatment (T1) and post-functional (T2) lateral cephalograms and MRI of TMJ were recorded. A total of 7 parameters were used to assess TMJ in all the 3 planes using MRI. Student’s t-test was carried out to compare pre- and post-treatment-induced changes. The mandible significantly moved forward (SNB, 3.71 + 0.91°; SND, 3.21 + 1.25°; Pg-OLp, 2.61 + 0.66mm, p<0.001) and there was distalizing effect on maxilla (SNA, –0.79 + 0.89°; A-OLp, –0.57 + 0.47mm, <0.001). Mean overjet correction of 4.43mm was achieved, of which 71.8% were skeletal changes. 65% of skeletal changes contributed to molar relationship correction. The forward positioning of mandible seems to be because of condylar and glenoid fossa remodelling, with condyle moving in anterior position within glenoid fossa (3.28 + 2.29) and articular disc moved posteriorly relative to condylar head (2.27 + 1.62°). Significant skeletal changes and TMJ remodelling were observed with bimaxillary anchored FFA in correcting skeletal Class II malocclusion.