Application of Virtual Mandibular Position in Temporomandibular Jont Reconstruction With Costochondral Graft in Children Jaw Deformity.

Hypothesis：Computer-aided design virtual mandibular position is feasible for costochondral graft growing and occlusion stabilizing in the one-stage treatment of children temporomandibular joint ankylosis (TMJA) or condyle absence with jaw deformity.

Methods: The inclusion criteria is children patients younger than 12 years old with unilateral TMJA or condyle absence. A virtual mandibular position is designed preoperatively according to the CT data of jaw and dentition. 3D printed templates and occlusal splints are used to guide the costochondral graft and mandibular position. During surgery, the affected ramus is reconstructed with costochondral grafting under the virtual mandibular position. After surgery, the occlusal splint is fixed to maxilla at least one month, and then, replaced by orthodontic functional appliance to promote downward growth of the maxilla. Occlusion, facial symmetry, costochondral graft growing would be evaluated and analysed until adulthood.