[Clinical application and accuracy analysis of occlusion-guided functional mandibular reconstruction]

To investigate the influence of the design and application of novel surgical template on the accuracy of reconstructed mandibula and implant position in occlusion-guided functional mandibular reconstruction, so as to provide guidance for clinical treatment.

Between January 2017 and May 2019, 11 patients with segmental mandible defects were treated, including 8 males and 3 females with an average age of 31.8 years (range, 19-45 years). There were 6 cases of ameloblastoma, 3 cases of keratocystic tumor, and 2 cases of ossifying fibroma. According to Urken classification of mandible defects, there were 1 case of CRB, 4 cases of RB, 2 cases of RBS, and 4 cases of SB. According to the occlusion relationship, a novel surgical template with the reconstruction titanium plate screws and implants drill-guided information was designed and manufactured. With the help of the novel surgical template, the "one and a half" fibula reconstruction mode was used for jaw functional reconstruction, and the implant supported denture was finally completed. The postoperative CT at 1 week were collected to analyze the morphology of the preoperative virtual design jaw and postoperative jaw. The coincidence of fibular reconstructed mandible (fibular upper barrel, fibular reconstructed ramus and condyle, and whole mandible) and implant in mandible were calculated. When the coincidence was less than 80%, it was considered that the deviation was obvious. Oral panoramic X-ray film and cone beam CT were examined at 6 months after operation to evaluate the osseointegration before implant repair.

None of the 11 flaps had postoperative vascular crisis. One flap occurred necrosis at 1 month after reconstruction combined with 3 implants failed, and had been removed at 6 months after reconstructed surgery; the others had no flap necrosis. One week postoperatively, the coincidence of the fibular upper barrel was 87.55%±3.08%, the whole mandible was 82.68%±5.94%, and the implant in mandible was 88.00%, with significant differences ( t=8.131, P=0.000; t=2.118, P=0.046; Z=4.070, P=0.000) when compared to 80%, respectively. The fibular reconstructed ramus and condyle was 77.82%±3.54%, with no significant difference ( t=-2.042, P=0.068) when compared to 80%. Six months postoperatively, oral panoramic X-ray film and cone beam CT showed that all 22 implants achieved osseointegration and the palatal mucosa transplantation was performed, then finally completed the denture rehabilitation at 6-9 months after operation. All patients were satisfied with their postoperative appearance.

The novel surgical template can guarantee the accuracy of functional mandible reconstruction guided by occlusal guidance, and ultimately achieve the beautiful contour of jaw and occlusal function reconstruction, and improve the patient's life quality.