Objective:To explore the effect of digital technology and 3D printing technology combined with non-vascularized ilium bone in repairing post-traumatic bone defect in maxillary anterior area.Methods:A retrospective case series study was performed to analyze clinical data of 8 patients with severe bone defect in maxillary anterior area after trauma admitted to First Affiliated Hospital of Zhengzhou University from June 2013 to January 2018. There were 6 males and 2 females, with the age of 18-43 years [(31.9±9.0)years]. The maxillary bone was reconstructed before surgery by employing digital technology. The intercept range of ilium was determined according to the best form of defect to be recovered. Then the model and guide plate was printed out by employing 3D print technology. The titanium mesh was prebended on the model. The bone was extracted and Onlay bone grafting was performed according to the guide plate. The implant restoration was performed 6 to 9 months after operation, and porcelain crown restoration was performed 4 to 6 months later. The iliac bone survival and postoperative complications were detected 6 months after bone grafting. The near-middle-far and vertical bone elevation of the alveolar ridge as well as bone elevation of lip palatal were measured before implantation. The condition around the implants was observed 6 months after porcelain crown restoration. The visual analogue score (VAS) was used to evaluate the pain after iliac bone transplantation and implantation. The implant stability coefficient (ISQ) was applied to assess the stability of the implants on the day and 4 months after operation.Results:All the patients were followed up for 24-48 months [(33.3±9.7)months]. Eight patients with non-vascularized iliums were all survived. There was one patient with mild infection after bone grafting and one patient with gingival inflammatory hyperplasia after implantation, both of whom were healed after treatment. There was no obvious peri-implant inflammation or absorption of the grafted bone. The increase in height of the alveolar on the mesial and distal bone, vertical bone and labial-palatal bone was 30.28-39.67 mm, 9.58-11.32 mm and 2.06-7.41 mm, respectively. All the implants showed good osseointegration. The VAS after implantation was (3.4±0.7)points, significantly alleviated compared with the preoperational level [(7.3±2.0)points] ( P<0.05). The ISQ was 84.4±1.9 at postoperative 4 months, showing no significant difference from that on the day after operation (72.9±1.4) ( P>0.05). Conclusions:In repair of severe bone defect in maxillary anterior area after trauma, the digital and 3D printing technology combined with non-vascularized ilium can improve the survival rate of bone grafts. The implant restoration after operation can reduce pain, restore the patients' facial appearance and achieve satisfactory oral physiological function.

Objective: To investigate the clinical manifestations and pathological changes of salivary duct carcinoma (SDC) and the relationship between them, so as to provide reference for the diagnosis of SDC. Methods: In this retrospective analysis 40 cases of SDC diagnosed from January 2012 to August 2018 in the Department of Pathology of the First Affiliated Hospital of Zhengzhou University were enrolled and the clinical and pathological characteristics were analyzed, 29 were male and 11 were female, the ratio of male to female was 2.64∶1, the median age was 59.0 years, the average course of disease was 3.5 years. The reported cases of SDC were reviewed and compared with patients of this study. Results: Among the 40 patients, 24 cases occurred in parotid gland, 9 cases in submandibular gland and 7 cases in small salivary glands; 24 cases had cancer cell infiltration and invasion of adjacent tissues, 11 cases had lymph node metastasis and 9 cases had distant metastasis at the time of diagnosis. Pathological results showed that 27 cases belonged to primary salivary duct carcinoma, 13 cases belonged to malignant transformation of pleomorphic adenoma; 10 cases invaded local nerve, 22 cases invaded glandular lobules and ducts. Immunohistochemical results showed that 33 cases were positive for androgen receptor, 27 cases were positive for cytokeratin-7, 22 cases were positive for human epidermal growth factor receptor-2, 8 cases were positive for gross cyst disease fluid protein 15. The proliferation index of nuclear antigen Ki-67 ranged from 10% to 90%. Among them 18 cases were over 50% and 22 cases were below 50%. Conclusions Salivary duct carcinoma is a rare and highly malignant tumor of the salivary gland. Accurate pathological diagnosis is helpful to inhibit the early local recurrence, distant metastasis and improve survival rate of salivary duct carcinoma.