Mandible-mounted splint-based navigation and intraoperative computed tomography for bone contouring in florid cemento-osseous dysplasia: A case report

Florid cemento-osseous dysplasia (FCOD) is usually asymptomatic; however, extensive jaw expansion may compromise mastication, speech, and facial contour. We report a case of bimaxillary FCOD with marked mandibular expansion treated by digitally assisted bone contouring. A 45-year-old woman presented with progressive mandibular enlargement, masticatory disturbance, and speech difficulty. Computed tomography (CT) showed high-density osseous lesions involving the jaws, and histopathological examination confirmed FCOD. Because bilateral mandibular involvement precluded contralateral mirroring, preoperative CT data were used to create a three-dimensional (3D) printed model, on which the target contour and planned bone reduction area were simulated. During surgery, an optical navigation system was used to confirm the extent and depth of bone reduction. To minimize registration error caused by mandibular mobility, a dynamic reference frame was attached to a custom mandibular splint containing embedded aluminum markers, allowing direct tracking of mandibular movement. Intraoperative CT in a hybrid operating room verified the symmetry and safety of the contouring. Postoperatively, mastication, speech, and facial contour improved without neurosensory disturbance or infection. At the 2-year follow-up, these improvements were maintained, with no radiographic regrowth.