Application of Rapid Prototyping for Temporomandibular Joint Reconstruction

Purpose To introduce the preliminary application of rapid prototyping (RP) for temporomandibular joint (TMJ) surgery. Materials and Methods This study included 11 consecutive patients (13 joints) seeking TMJ replacement. All patients had previously undergone 3-dimensional computed tomography (CT) scanning (0.625-mm slice thickness) of the craniofacial skeleton. The data from CT scanning in DICOM (Digital Imaging and Communications in Medicine) format were input into the interactive Simplant CMF software program (Materialise Medical, Leuven, Belgium). Preoperative planning included segmentation and osteotomies. The movements of the jaw bones were simulated by use of Simplant CMF. The affected mandible was reconstructed based on the contralateral side. Then, the titanium plate was shaped on the reconstructed model before surgery. The bone graft was transplanted by the shaped titanium plate during the operation to reconstruct the TMJ. Twenty-four patients who underwent traditional surgery were used as the control group. The operative time of the 2 groups was analyzed with the SPSS software package, version 13.0 (SPSS, Chicago, IL), with the Student t test. The data from CT scanning in the experimental group before and after surgery were compared by paired t test. Results All the incisions healed primarily without any complications. All patients were satisfied with the operation, because of their symmetric faces and good occlusion. Postoperative magnetic resonance imaging confirmed the position of the transplanted costochondral cartilage in the glenoid fossa. A group t test showed that the operative time was longer in the control group (mean, 7.09 hours) than that in the RP group (mean, 5.67 hours). Three parameters (condyle-incisor, condyle–mental foramen, and condyle-angle) from the postoperative CT scan were analyzed by paired t test, and there was no significant difference between the 2 sides. Conclusion RP technology provides an advanced method for TMJ reconstruction that can make the TMJ reconstruction more accurate and symmetric, improve the mandible's function, and consequently, enhance the reconstructive effect.