Correction of Mandibular Asymmetry With Bilateral Asymmetric Custom-Made 3D Implant

Unilateral mandibular hypoplasia affects not only the involved side but also the contralateral hemimandible. Thus, treatment must address bilateral deformities. The authors present a novel bilateral CAD/CAM titanium onlay implant design for unilateral mandibular hypoplasia and evaluate outcomes using objective and patient-reported measures.

Thin-slice CT scans were processed with Mimics® software. The unaffected hemimandible was repositioned to the midline using the TMJ as a pivot, and its mirror image was used to create the contralateral side. Bilateral custom implants were generated through the subtraction of corrected from native images and 3D printed. Eight male patients underwent correction via extraoral incision, with fat grafting for contour refinement. Follow-up was at least 12 months. PROMs included the Appearance Evaluation Subscale (AES) of the Multidimensional Body Self-Relations Questionnaire and the Rosenberg Self-Esteem Scale (RSE). Objective outcomes were assessed with the Facial Asymmetry Index (FAI).

Five patients had congenital asymmetry, and three had post-traumatic deformities. All tolerated surgery without early complications. Fat grafting was used in five cases, four of which involved hemifacial microsomia. AES and RSE scores significantly improved at 12 months compared with preoperative values. FAI also demonstrated a significant reduction in facial asymmetry.

Correction of unilateral mandibular hypoplasia creates bilateral deformities. Our bilateral CAD/CAM titanium implant approach provides a novel solution, though most patients also require soft tissue adjustment. Despite being time-consuming and costly, future technological advances are expected to increase efficiency and reduce expense.