Objective To investigate the effect of the multi?material artifact reduction (MMAR) algorithm of spectral CT in reducing the beam hardening artifacts in dental restoration material. Methods Three?unit fixed bridge restorations were fabricated on the first to third molars in pig jaw. Gold alloy, zirconia, cobalt chromium alloy, nickel chromium alloy and pure titanium were used as materials for these fixed bridges. After restoration delivery, the pig jaw was scaned using energy spectrum CT machines. Images in regular 120 kVp scan mode were used as conventional group, and reconstructed single?energy horizontal images of 80, 90, 100, 110, 120, 130 and 140 keV in energy spectrum scanning mode were used as energy spectrum group, and reconstructed images applied MMAR technology in energy spectrum scanning mode were used as energy spectrum MMAR group. Each group was scanned 10 times to measure CT value and noise of muscles around dental prosthetic materials and adjacent non?artifact layers. Artifact index was calculated. Two radiologists scored the image quality of each group subjectively. Kruskal Wallis rank sum test was used to compare the difference of image noise, artifact index and subjective score among the control group and the best keV condition in the energy spectrum group and the energy spectrum MMAR group. Results The image noise of energy spectrum group and energy spectrum MMAR group decreased gradually with the increase of single energy level. The artifact index of pure titanium restorations in conventional group, energy spectrum group and energy spectrum MMAR group were 71.0±8.0, 21.4±2.7 and 14.7±2.7 respectively, and these values were significantly lower than those of other materials in the same group (P<0.05). The subjective image quality scores in energy spectrum MMAR group were as follows: 3.0±0.2 for gold alloy, 4.3±0.5 for zirconia, 3.0±0.4 for cobalt chromium alloy, 3.1±0.4 for cobalt chromium alloy, and 4.6± 0.5 for pure titanium. These scores were significantly smaller than those in the conventional group (P<0.05). There was no significant difference in noise between energy spectrum group and energy spectrum MMAR group (P>0.05), and the noise values in energy spectrum group and energy spectrum MMAR group were significantly lower than that in the conventional group (P<0.05). Conclusions Artifacts of pure titanium is minimal. Energy spectrum CT combined with MMAR technology can effectively reduce the artifacts of gold, zirconia, cobalt?chromium alloy, nickel?titanium alloy and pure titanium. This technique can be used as an effective method to remove artifacts of dental prosthesis.

Objective To investigate the effect of EZH2 on apoptosis and radiosensitivity of squamous cell carcinoma of tongue.Methods Tongue squamous carcinoma cells Tca-8113 were transfected with small interfering RNA of EZH2 (EZH2 siRNA1,EZH2 siRNA2) and its negative controls (siRNA-NC),the expression levels of EZH2 were detected by RT-PCR and Western blot and EZH2 siRNA2 was used for further studied since its better interference efficiency.The cells with siRNA transfection were irradiated with 8 Gy doses,and cell proliferation was detected by MTT,apoptosis was detected by flow cytometry,the expression of p-STAT3,STAT3 and Cleaved Caspase-3 was detected by Western blot.In addition,the cells were irradiated with 0,2,4,6,and 8 Gy to detect radiosensitivity by cell colony formation assay.Results EZH2 siRNA1 and EZH2 siRNA2 decreased the expression of EZH2 in Tca-8113 cells and EZH2 siRNA2 had a better interference efficiency (tmRNA =8.660,PmRNA ＜ 0.01;tprotein =2.883,Pprotein ＜0.05).The apoptotic rate in the EZH2 siRNA group was (29.90 ± 1.64)％,and was increased by 8 Gy irradiation to (38.17 ± 1.59) ％ (t =4.742,P ＜ 0.05).At the same time,EZH2 siRNA reduced the level of p-STAT3,but promoted the expression of Cleaved Caspase-3 protein,and enhanced the sensitivity of Tca-8113 cells to 1.668-times of control.Conclusions Interfering EZH2 could promote apoptosis,inhibit proliferation and increase radiosensitivity of squamous cell carcinoma of tongue.

Objective To evaluate the clinical outcomes of internal fixation with extra-articular distal humerus locking compression plate (LCP) for the treatment of mid-distal humerus diaphyseal fracture.Methods From December 2012 to December 2016,a cohort of 22 patients with mid-distal humerus shaft fracture were treated by open reduction and internal fixation using extra-articular distal humerus LCP.They were 14 males and 8 females with an average age of 42.7 years (range,from 18 to 86 years).According to AO classification,there were 13 cases of type 12-A,7 cases of type 12-B,and 2 cases of type 12-C.The surgical time,intra-operative blood loss and hospital stay were recorded.The clinical outcomes were evaluated by the Mayo elbow performance score (MEPS) at the last follow-ups.Results Surgical time ranged from 46 to 95 minutes with an average of 57 minutes.The average blood loss was 220 mL (range,from 150 to 400 mL).The average hospital stay was 10.5 days (range,from 9 to 13 days).The mean follow-up was 23.8 months (range,from 6 to 48 months).Bone union was achieved in 21 cases after an average of 4.6 months (range,from 3 to 9 months),and one patient experienced bone non-union which was uneventfully healed after secondary auto platelet rich plasma (PRP) graft management.The average MEPS elbow performance score was 88.2,resulting in 16 excellent,4 fine and 2 fair cases (excellent and fine rate:90.9％).Conclusions Since extra-articular distal humerus LCP can provide stable internal fixation,facilitating early postoperative rehabilitation,it may be considered an effective alternative osteosynthesis for mid-distal comminuted humeral diaphyseal fractures.

Objective:To investigate the clinical characteristics and imaging manifestations of primary bone lymphoma (PBL) located in the jaw.Methods:Clinical data of 14 PBL patients admitted to The First Affiliated Hospital of Zhengzhou University from January 2014 to April 2019 were retrospectively analyzed, which including age, gender, location, chief complaint, laboratory test, imaging manifestations and so on.Results:Among the 14 PBL patients, 10 were male and 4 were female. Age range from 4 to 79 years, median age was 56 years old. There were 6 cases involved maxillary, 7 cases involved mandible and 1 case involved mandible and maxillary simultaneously. Twelve patients were admitted with local mass as the chief complaint, 3 had a history of toothache, 4 had loosen tooth and 2 had numbness of lips and cheeks. Two cases of oral mass with mucosal surface ulcer or abscess formation. One case complained of fever, night sweats and other systemic symptoms. The imaging findings showed 8 cases of osteolytic lesions, 1 case of sclerosis, 4 cases of mixed lesions and 1 case of cystic lesions. One case had periosteum reaction. In 12 cases, there was an obvious mass, which was characterized by the large soft-tissue mass and marrow changes were associated with surprisingly little cortical destruction.Conclusions:PBL is more common in middle aged male. The upper and lower jaw bones can be involved. Clinical and imaging manifestations lack characteristics, and common dental or periodontal symptoms such as toothache, tooth loosening, and paresthesia may occur. However, the imaging characteristics of large soft tissue masses with small degree of bone destruction can be used as an important basis for the differential diagnosis of osteomyelitis, squamous cell carcinoma, osteosarcoma and other diseases.

Objective:To explore the strategy and experience for treating maxillofacial and cervical multi-space infection combined with descending necrotizing mediastinitis (DNM) via multidisciplinary team (MDT) collaboration.Methods:A total of 36 patients with maxillofacial and cervical multi-space infection complicated with DNM admitted to the First Affiliated Hospital of Zhengzhou University from July 2011 to July 2019 were included in the study. The clinical data of the patients were retrospectively analyzed, including gender, age, symptoms at admission, source of infection, preoperative and postoperative evaluation indicators, MDT strategy and prognosis.Results:There were 26 males and 10 females with an average age of (51.6±17.6) years (8-80 years). The course of disease before admission was (8.9±8.4) days (2-30 days). All patients were admitted with maxillofacial and neck swelling and pain as the main complaints. Odontogenic infection accounted for 39% (14/36), throat floor swelling and pain accounted for 25% (9/36) and unknown maxillofacial swelling accounted for 36% (13/36). There were 28 cases receiving surgical treatment, 26 cases were cured and discharged (72%), 10 cases died (28%). In the patients treated with multidisciplinary therapy (mainly by surgery), the white blood cell count, neutrophil percentage, C-reactive protein and procalcitonin levels were significantly improved compared with those at admission at each observation time point after operation ( P<0.05). The length of stay was positively correlated with the levels of C-reactive protein ( r=0.545, P<0.05) and procalcitonin ( r=0.504, P<0.05). The prognosis of patients treated with surgery (26/28) was better than that of patients without surgery (0/8) ( P<0.01). Conclusions:The patients with maxillofacial and cervical multi-space infection combined with DNM might be in critical condition. The surgical based MDT strategy has an important impact on the prognosis of patients. White blood cell count and other inflammatory indicators monitoring can effectively observe the changes of the patient′s condition.

Objective: To investigate the effect of the multi-material artifact reduction (MMAR) algorithm of spectral CT in reducing the beam hardening artifacts in dental restoration material. Methods: Three-unit fixed bridge restorations were fabricated on the first to third molars in pig jaw. Gold alloy, zirconia, cobalt chromium alloy, nickel chromium alloy and pure titanium were used as materials for these fixed bridges. After restoration delivery, the pig jaw was scaned using energy spectrum CT machines. Images in regular 120 kVp scan mode were used as conventional group, and reconstructed single-energy horizontal images of 80, 90, 100, 110, 120, 130 and 140 keV in energy spectrum scanning mode were used as energy spectrum group, and reconstructed images applied MMAR technology in energy spectrum scanning mode were used as energy spectrum MMAR group. Each group was scanned 10 times to measure CT value and noise of muscles around dental prosthetic materials and adjacent non-artifact layers. Artifact index was calculated. Two radiologists scored the image quality of each group subjectively. Kruskal Wallis rank sum test was used to compare the difference of image noise, artifact index and subjective score among the control group and the best keV condition in the energy spectrum group and the energy spectrum MMAR group. Results: The image noise of energy spectrum group and energy spectrum MMAR group decreased gradually with the increase of single energy level. The artifact index of pure titanium restorations in conventional group, energy spectrum group and energy spectrum MMAR group were 71.0±8.0, 21.4±2.7 and 14.7±2.7 respectively, and these values were significantly lower than those of other materials in the same group (P<0.05). The subjective image quality scores in energy spectrum MMAR group were as follows: 3.0±0.2 for gold alloy, 4.3±0.5 for zirconia, 3.0±0.4 for cobalt chromium alloy, 3.1±0.4 for cobalt chromium alloy, and 4.6±0.5 for pure titanium. These scores were significantly smaller than those in the conventional group (P<0.05). There was no significant difference in noise between energy spectrum group and energy spectrum MMAR group (P>0.05), and the noise values in energy spectrum group and energy spectrum MMAR group were significantly lower than that in the conventional group (P<0.05). Conclusions Artifacts of pure titanium is minimal. Energy spectrum CT combined with MMAR technology can effectively reduce the artifacts of gold, zirconia, cobalt-chromium alloy, nickel-titanium alloy and pure titanium. This technique can be used as an effective method to remove artifacts of dental prosthesis.