A 24-year-old female of Colombian origin presented with progressive facial asymmetry of 9 years evolution. Orthodontic pre-surgical treatment was undertaken in 2012 and 2013, but surgery was declined, and orthodontic appliances were subsequently removed. In 2021 clinical examination showed facial asymmetry of the lower third of the face with deviation to the left side, mild bilateral paranasal depression, adequate dental exposure at rest or smile, with an even superior occlusal plane and lower mandibular edges. A slight convex profile from mild retrusion of the lower jaw was observed.
Intraoral examination showed acceptable alignment of arches, a left posterior crossbite, left deviation of the inferior dental midline, and transverse discrepancy of dental arches due to reduced amplitude of the upper jaw. Plain X-rays confirmed clinical findings and suggested predominantly transverse asymmetry. Bone scintigraphy revealed increased metabolism of the right mandibular condyle (20% increase in uptake compared to contralateral), and computerized tomography (CT) confirmed asymmetry from hyperplasia of the right condyle and the skeletal and dental asymmetry described above. The patient was diagnosed with asymmetric dentofacial deformity secondary to right condylar hyperplasia, and the decision was taken to treat with corrective surgery (Fig. 1).
Orthognathic surgery
CT segmentation of intraoral and planned occlusion scans were fused, and 3D reconstruction was created with Mimics™ and Proplan™ software from Materialise Medical™. The surgical virtual plan included the following procedures:
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Le Fort I osteotomy in two segments
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Mandibular sagittal osteotomies
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Chin osteotomy
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High condylectomy of the right temporomandibular joint
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Repositioning of segments
Considering the previous alignment of arches and the indication for a “surgery first” approach, surgical feasibility stone models were developed for sagittal segmentation of the upper jaw, resulting in satisfactory occlusion.
A surgery first plan was chosen, followed by the design of surgical bite splints in Proplan™ (Materialise Medical), as well as the design of cutting guides for Le Fort I (in two segments), sagittal, and chin osteotomies.
During the planning stage, patient-specific guides and miniplates were designed for the osteosynthesis of upper and lower jaw osteotomies. Biomodels of the osteotomy designs and the postoperative positions were printed in 3D (Figs. 2, 3 and 4). The latter evaluate the quality of the printed cutting guides and osteosyntheses. Biomodels and guides were made with polyamide 12, a medical-grade polymer, using Selective Laser Sintering in an EOS P396 printer. The patient-specific implants were manufactured in metallic alloys of Titanium Ti6A14V ELI (grade 23), an implantable metal offering excellent mechanical and biomedical features, using Electric Beam Melting in an ARCAM Q10 printer. All of the designs were printed at Mizar Health (Alcor Group, Vitoria, Spain).
The surgical procedure was performed under general anaesthetic. The cutting guides and patient-specific implants were deployed. A condylectomy specimen was sent for histopathology that confirmed condylar hyperplasia. Given the transverse change of the upper jaw, a postoperative occlusal splint was designed to increase stability and reduce the risk of recurrence. It was reinforced with a trans palatine bar fixed with wires to teeth in the maxilla (Fig. 4). The patient was discharged 24 hours postoperatively with recommendations for local wound care, warning signs, diet, medication, and outpatient appointments.
Weekly outpatient follow-up during the first postoperative month showed occlusal stability, resolution of edema, and no signs of infection. Radiography confirmed the stability of osteotomies and osteosyntheses (Fig. 5). Later on, intra and extra-oral sutures and bite splints were removed. Orthodontic management was initiated to adjust dental positions.