OBJECTIVETo probe the implant-bone-interface stress distribution of zygomatic implant denture concerning different implant sites.

METHODSThree-dimensional finite element model for severe atrophy maxillary posterior-tooth area was established biomechanically in this study by computer technique and zygomatic implant was simulated into the model in the first-maxillary-premolar region, the second-maxillary-premolar region, the first-maxillary-molar region and the second-maxillary-molar region respectively. Vertical loading, buccal (30 degrees) loading and lingual (30 degrees) loading were preformed, 100 N. Then these load cases were calculated and analyzed.

RESULTS1) When the implant site was placed in the first-maxillary-premolar region, the buccal side of zygomatic implant exposed out of the bone and didn't meet the clinical request. 2) As far as the tensile stress peak value in the maxillary posterior-tooth area was concerned, the highest value was recorded when the implant was placed in the second-maxillary-molar region, and then the medium value was recorded when the implant was placed in the second-maxillary-premolar region, and the smallest was recorded when the implant in the first-maxillary-molar region. As far as the compressive stress peak value in the maxillary posterior-tooth area was concerned, the highest value was recorded when the implant was placed in the second-maxillary-molar region, and then the medium was recorded when the implant was in the first-maxillary-molar region, and the smallest value was presented when the implant was in the second-maxillary-premolar region. As far as the tensile and compressive stress peak values in the zygomatic area were concerned, the highest value was recorded when the implant was in the second-maxillary-premolar region, and then the medium value when the implant was in the first-maxillary-molar region, and the smallest when the implant was in the second-maxillary-molar region.

CONCLUSIONThe first-maxillary-molar region is the best implant site of zygomatic implant denture.

Bicuspid ; Dental Implants ; Dental Prosthesis, Implant-Supported ; Dentures ; Finite Element Analysis ; Humans ; Maxilla ; Molar ; Stress, Mechanical

Objective To investigate the treatment and prevention of infection after alveolar crest onlay bone graft. Methods From January 2006 to May 2010, 11 infection cases after onlay graft on alveolar crest were reviewed to evaluate the infection time, clinical situation, treatment measure, and therapeutic effect Results The infection of all 11 cases occurred about 15 days after bone graft, which showed either soft tissue fistulae or bone graft exposure in the oral cavity. Three cases failed because of persistent infection.The infection of the other 8 cases was controlled after a series of comprehensive therapy, and most of the bone graft was reserved and implant restoration finally completed. Conclusions After the effective and comprehensive therapy, infected bone graft can be reserved. But to ensure the survival rate of bone graft, the most important thing is to prevent infection in perioperative period.

Aged ; Fatty Liver ; complications ; metabolism ; Female ; Humans ; Insulin Resistance ; Lipids ; Liver ; metabolism ; Male ; Metabolic Diseases ; metabolism ; Middle Aged ; Non-alcoholic Fatty Liver Disease

OBJECTIVETo investigate the effects of alveolar bone resorption on stress of tooth/implant-supported restoration connected by precision attachment using three-dimensional finite element(FEM) approach.

METHODSThe FEM was applied to analyze the stress distribution of tooth/implant-supported restoration connected by precision attachment under various loading conditions when the alveolar bone was absorbed to different level.

RESULTSThe stress values of the tooth, implant and their surrounding bone increased when their surrounding bone decreased by bone absorption.

CONCLUSIONThe stress values of the tooth, implant and their surrounding bone were closely related with the bone resorption.

Alveolar Process ; Bone Resorption ; Bone and Bones ; Dental Prosthesis, Implant-Supported ; Dental Stress Analysis ; Finite Element Analysis ; Humans

Objective To study the bone biomechanics of the rabbit osteoporosis models induced by dexamethasone sodium phosphate injection (DX) using a combined treatment modality of 99Tc-MDP and GuKangLing.Methods Rabbits were intramuscularly injected with DX (2 mg/kg) twice a week for 6 weeks.The animal osteoporosis model group (Group C) and normal group (Group A) were compared to confirm the model was available.Another control group (Group B),the osteoporosis control group (Group D) were set for the comparison at the end of the experiment.The 99Tc-MDP therapy group (Group E),GuKangLing therapy group (Group F) and 99Tc-MDP plus GuKangLing therapy group (Group G) were included in the study.The treatment lasted for 16 weeks.The bone biomechanics,cytopathology bone histomorphology,bone mineral density (BMD),X-ray,CT,bone scintigraphy and serum bone alkaline phosphatase (BALP)and P (bone gla protein) were chosen as the markers or methods to evaluate the treatment results (excellent,effective and invalid).The analysis of variance (ANOVA) and t-test were used for group comparison analysis.Results Cytopathology result indicated that there was no bone trabecula destruction in Group A.However,there was distinct bone destruction in Group C.The bone biomechanics (left femur head (265.914 ±52.773) N,L4(369.671 ±94.919) N),BMD(left femur (0.238 ±0.016) g/cm2,L4(0.236 ±0.016) g/cm2)and bone histomorphology ( (66.230 ± 10.848) ％ ) in Group C reduced clearly as compared with Group A ((405.343±55.410) N,(750.870±53.718) N,(0.294±0.017) g/cm2,(0.302±0.023) g/cm2,( 131.500 ± 21.846) ％ ) ( t ≥4.550,all P ＜ 0.01 ).Radionuclide bone scan also showed that the uptake of tracers was higher by the main arthrosis in Group C than that in Group A.Vertebra was not clearly visualized on bone scan image.There were significant differences between Group A and Group C in serum BALP and P ((45.000±7.303) vs (12.485 ±1.512) U/L,(0.168±0.018) vs (0.115 ±0.017) μg/L,t =4.126,5.476,both P ＜ 0.01 ),which indicated that the animal osteoporosis model was available.The pathological results showed an improved recovery of bone structure and trabecular in Groups E and G,but a worse recovery in Group F.Biomechanics result in Groups E and G (left femur head (386.457 ±77.077) N and (432.771 ± 17.525) N,L4(649.550 ± 126.859) N and (655.443 ±76.555) N) improved apparently,which were similar to Group B.The radiotracer uptake in Group F was lower than that in group D.The bone biomechanics,bone histomorphology,BMD,serum BALP and P after the treatment showed significant differences in Groups E,F and G (F:8.556 - 31.608,all P＜0.01 ),and the bone biomechanics result in Group G was a little better than that in Group E (t =2.625,P ＜ 0.05 ).The results of Group G and E were considered as excellent,and Group F was considered as effective.Conclusions The treatment of 99Tc-MDP combined with GuKangLing could improve the bone biomechanics of rabbit osteoporosis models and may be a potential method to increase the bone strength for resisting external force.

OBJECTIVETo search for an effective method of reducing intraoperative blood loss in radical retropubic prostatectomy (RRP).

METHODSWe performed RRP for 100 patients with prostate cancer, 50 (group A) with the Walsh or Poor method for handling the dorsal venous complex (DVC), and the other 50 (group B) through the following three additional procedures for hemostasis: first placing a #7 prophylactic suture in the distal position of DVC, then ligating the vascular bundle of the prostatic apex with continuous 4-0 Vicryl sutures, and lastly placing a 4-0 absorbable suture followed by freeing the neurovascular bundle (NVB) or freeing NVB before suturing the remained levator ani myofascia and the deep layer of Denovilliers' fascia above the rectal serosa with 4-0 Vicryl. We assessed the effects of the three hemostatic methods in RRP by comparing the volumes of intraoperative blood loss and transfusion, operation time and perioperative levels of hemoglobin.

RESULTSThere were no significant differences between groups A and B in age, PSA, Gleason score, clinical stage, prostate volume, operation time and perioperative hemoglobin levels (P>0.05). The volumes of intraoperative blood loss and transfusion were markedly higher in group A ([1103.00 +/- 528.03] ml and [482.00 +/- 364.60] ml) than in B ([528.00 +/- 258.96] ml and [140.00 +/- 266.28] ml) (P<0.05).

CONCLUSIONIntraoperative blood loss in RRP could be significantly decreased by placing a prophylactic hemostatic suture in the distal position of DVC, continuous suture of the vascular bundle of the prostatic apex after cutting off the urethra, and placing a fine absorbable suture above NVB or continuous suture of the remained levator ani mony fascia and the deep layer of Denovilliers'fascia above the rectal serosa with absorbable sutures after freeing NVB.

Aged ; Blood Loss, Surgical ; prevention & control ; Hemostatic Techniques ; Humans ; Male ; Middle Aged ; Prostatectomy ; methods ; Prostatic Neoplasms ; surgery

A strategy based on immunomagnetic nanospheres ( IMNs ) for rapid, efficient and accurate detection of lymphnode metastasis carcinoma cells ( LNMCCs ) was developed in this study. First, IMNs processing magnetism and biological targeting were fabricated by the approach developed by our group previously. Then, LNMCCs in lymph node fine needle aspiration ( LNFNA) specimens were separated and enriched by the immunomagnetic isolation using IMNs. At last, the captured cells were identified with Wright's staining and immunocytochemistry ( ICC) . The separation and enrichment of LNMCCs with immunomagnetic isolation could reduce the background interference of LNFNA specimens effectively; the identification with Wright ' s staining and ICC offered more reliable information for accurate diagnosis, so the sensitivity, specificity and overall diagnostic accuracy had an obvious improvement compared with the conventional cytologic diagnosis. Besides, the simple and rapid incubation of LNFNA specimens with IMNs needed just 5 min, so the cytomorphology of captured LNMCCs could be intactly retained, which enabled to provide important basis for classifying lymphnode metastasis carcinoma ( LNMC ) and the subsequent pathological study. Moreover, the specific capture of epithelial carcinoma cells in LNFNA specimens with IMNs could make a definite diagnosis of the captured cells as LNMCCs, thus realizing the differentiated diagnosis of LNMC and malignant lymphoma. Additionally, this strategy exhibited successful LNMCCs detection in LNFNA specimens from 110 patients and had higher sensitivity ( 98 . 0%) , specificity ( 100 . 0%) , and overall diagnostic accuracy (98. 2%) than the conventional cytologic diagnosis. Therefore, it was a new attempt to use IMNs for detection of LNMCCs in LNFNA specimens from LNMC patients, and offered new ideas for LNMC diagnosis and study.

Objective:To compare the clinical effect of three indwelling methods of plastic biliary stent on relieving obstructive jaundice caused by unresectable hilar cholangiocarcinoma.Methods:A retrospective study was performed on data of 61 patients with obstructive jaundice caused by unresectable hilar cholangiocarcinoma from April 2014 to December 2020 in Cancer Hospital, Chinese Academy of Medical Sciences. Plastic biliary stent placement was used to relieve jaundice, including 18 cases of intragastric indwelling at the end of biliary stent, 31 cases of duodenal papilla indwelling at the end of biliary stent, and 12 cases of horizontal portion of duodenum indwelling at the end of biliary stent. Incidence of fever within 2 weeks, perioperative mortality, 90-day obstruction rate, and median stent patency period were followed up and the results were analyzed.Results:The incidence of fever within 2 weeks of the three groups were significantly different [66.7% (12/18), 58.1% (18/31) and 16.7% (2/12), χ2=7.30, P=0.026]. There were no statistically differences in the perioperative mortality [0 (0/16), 3.2% (1/31) and 0 (0/10), χ2=1.09, P=1.000], 90-day obstruction rate [52.9% (9/17), 48.3% (14/29) and 40.0% (4/10), χ2=1.91, P=0.589], or median stent patency period (66.0 d, 91.5 d and 94.0 d, Z=4.96, P=0.084) among three groups. Conclusion:Patients with biliary plastic stents with ends placed at the horizontal portion of the duodenum show lower incidence of fever within two weeks after implantation, and similar median stent patency period, 90-day obstruction rate and perioperative mortality compared with intragastric indwelling and duodenal papilla indwelling groups. Therefore, biliary plastic stents with ends placed at the horizontal portion of the duodenum should be recommended as the preferred procedure.

Objective:To evaluate artificial intelligence constructed by deep convolutional neural network (DCNN) for the site identification in upper gastrointestinal endoscopy.Methods:A total of 21 310 images of esophagogastroduodenoscopy from the Cancer Hospital of Chinese Academy of Medical Sciences from January 2019 to June 2021 were collected. A total of 19 191 images of them were used to construct site identification model, and the remaining 2 119 images were used for verification. The performance differences of two models constructed by DCCN in the identification of 30 sites of the upper digestive tract were compared. One model was the traditional ResNetV2 model constructed by Inception-ResNetV2 (ResNetV2), the other was a hybrid neural network RESENet model constructed by Inception-ResNetV2 and Squeeze-Excitation Networks (RESENet). The main indices were the accuracy, the sensitivity, the specificity, positive predictive value (PPV) and negative predictive value (NPV).Results:The accuracy, the sensitivity, the specificity, PPV and NPV of ResNetV2 model in the identification of 30 sites of the upper digestive tract were 94.62%-99.10%, 30.61%-100.00%, 96.07%-99.56%, 42.26%-86.44% and 97.13%-99.75%, respectively. The corresponding values of RESENet model were 98.08%-99.95%, 92.86%-100.00%, 98.51%-100.00%, 74.51%-100.00% and 98.85%-100.00%, respectively. The mean accuracy, mean sensitivity, mean specificity, mean PPV and mean NPV of ResNetV2 model were 97.60%, 75.58%, 98.75%, 63.44% and 98.76%, respectively. The corresponding values of RESENet model were 99.34% ( P<0.001), 99.57% ( P<0.001), 99.66% ( P<0.001), 90.20% ( P<0.001) and 99.66% ( P<0.001). Conclusion:Compared with the traditional ResNetV2 model, the artificial intelligence-assisted site identification model constructed by RESENNet, a hybrid neural network, shows significantly improved performance. This model can be used to monitor the integrity of the esophagogastroduodenoscopic procedures and is expected to become an important assistant for standardizing and improving quality of the procedures, as well as an significant tool for quality control of esophagogastroduodenoscopy.

Objectives:To develop and validate predictive models for esophageal squamous cell carcinoma (ESCC) using circulating cell-free DNA (cfDNA) terminal motif analysis. The goal was to improve the non-invasive detection of early-stage ESCC and its precancerous lesions.Methods:Between August 2021 and November 2022, we prospectively collected plasma samples from 448 individuals at the Department of Endoscopy, Cancer Hospital, Chinese Academy of Medical Sciences for cfDNA extraction, library construction, and sequencing. We analyzed 201 cases of ESCC, 46 high-grade intraepithelial neoplasia (HGIN), 46 low-grade intraepithelial neoplasia (LGIN), 176 benign esophageal lesions, and 29 healthy controls. Participants, including ESCC patients and control subjects, were randomly assigned to a training set ( n=284) and a validation set ( n=122). The training cohort underwent z-score normalization of cfDNA terminal motif matrices and a selection of distinctive features differentiated ESCC cases from controls. The random forest classifier, Motif-1 (M1), was then developed through principal component analysis, ten-fold cross-validation, and recursive feature elimination. M1's efficacy was then validated in the validation and precancerous lesion sets. Subsequently, individuals with precancerous lesions were included in the dataset and participants were randomly allocated to newly formed training ( n=243), validation ( n=105), and test ( n=150) cohorts. Using the same procedure as M1, we trained the Motif-2 (M2) random forest model with the training cohort. The M2 model's accuracy was then confirmed in the validation cohort to establish the optimal threshold and further tested by performing validation in the test cohort. Results:We developed two cfDNA terminal motif-based predictive models for ESCC and associated precancerous conditions. The first model, M1, achieved a sensitivity of 90.0%, a specificity of 77.4%, and an area under the curve (AUC) of 0.884 in the validation cohort. For LGIN, HGIN, and T1aN0 stage ESCC, M1's sensitivities were 76.1%, 80.4%, and 91.2% respectively. Notably, the sensitivity for jointly predicting HGIN and T1aN0 ESCC reached 85.0%. Both the predictive accuracy and sensitivity increased in line with the cancer's progression ( P＜0.001). The second model, M2, exhibited a sensitivity of 87.5%, a specificity of 77.4%, and an AUC of 0.857 in the test cohort. M2's sensitivities for detecting precancerous lesions and ESCC were 80.0% and 89.7%, respectively, and it showed a combined sensitivity of 89.4% for HGIN and T1aN0 stage ESCC. Conclusions:Two predictive models based on cfDNA terminal motif analysis for ESCC and its precancerous lesions are developed. They both show high sensitivity and specificity in identifying ESCC and its precancerous stages, indicating its potential for early ESCC detection.