Hereditary hemochromatosis is a rare autosomal genetic disorder that can cause multi-organ dysfunction in the liver,pancreas,spleen,heart and pituitary gland,with diverse clinical manifestations,make the diagnosis difficult.In recent years,with the deepening of clinical understanding and the development of genetic diagnosis tools,the diagnostic rate of this disease has increased significantly.In this paper,we report a case of hereditary hemochromatosis type 3 involving multiple organs and complicated by severe heart failure,aiming to improve the clinicians'understanding of this disease and reduce the leakage and misdiagnosis.

Objective:To establish a finite element model of the mandibular first molar with three wall defects, simulate the repair effect of fiber post porcelain crown and modified inlay, and analyze the effect of crown defect location on abutment stress.Methods:One intact mandibular first molar was extracted due to periodontal disease. Conical beam computed tomography (CBCT) was used to obtain the data, Mimics, Geomagic, and Ansys software were used to construct the mandibular first molar model, and 8 groups of models (groups A, B, C, D of fiber post all-porcelain crown and groups E, F, G, and H of modified onlays) were established according to different locations and repair methods of the three wall defects. Four forces (F1, F2, F3 and F4) were selected to compare the maximum Von Mises stress and its distribution.Results:The extreme values of dentin Von Mises stress were 19.334 9-19.907 1 MPa(F1), 8.295 47-8.466 08 MPa(F2), 19.433 5-19.441 4 MPa(F3) for fiber post all-porcelain crown restoration (group A, B, C and D models), respectively. 36.109 3-36.199 8 MPa(F4); The maximum values of Von Mises stress were 19.493-19.864 8 MPa(F1) in modified high inputate restoration (E, F, G, H). 9.077 35-9.317 12 MPa(F2), 22.770 6-23.541 2 MPa(F3), 35.724 2-35.989 7 MPa(F4). There was little change among the models. The extreme value of dentin stress increased with the increase of loading Angle. Under the same defect mode, the extreme value of dentin stress in groups A, B, C and D was less than that in groups E, F, G and H at F2 and F3. At F1 and F4, the extreme values of dentin stress in the eight groups were similar, but the dentin stress concentration area in groups A, B, C and D was located on the tooth surface, and the stress concentration area appeared in the pulp chamber in groups E, F, G and H.Conclusions:The position of the defect has no significant effect on the repairing effect of the modified inlay and the fiber post porcelain crown. The fiber post porcelain crown is more beneficial to disperse the dentin stress.

Objective:To analyze the anatomical morphological characteristics of the trabecular bone of human mandibular condyle by observing the distribution of volume of interests (VOI).Methods:The micro-CT images of a right condyle specimen of a 61-year-old adult male was analyzed in this study. The cylindrical VOI with both diameter and height of 2 mm were arranged, according to a certain pattern, as many as possible at various levels within the trabecular bone of the condyle. Each VOI had no intersection area. The selected VOI were divided into 5 parts: medial part, middle part, lateral part, anterior part and posterior part, with 6 layers from top to bottom. And the distribution of the overall anatomical morphological characteristics of three-dimensional (3D) images of the trabecular bone of the condyle was analyzed by using seven morphological parameters of each VOI, i.e. bone mineral density (BMD), bone volume/total volume (BV/TV), bone surface area/bone volume (BS/BV), trabecular thickness (Tb.Th), trabecular bone number (Tb.N), trabecular spacing (Tb.Sp) and trabecular bone pattern factor (Tb.Pf).Results:In the present study, totally 34 VOI were selected from the condyle specimen.The morphological distribution of the VOI was uneven in the 3D structure of the trabecular bone of the human condyle. BMD, BV/TV, Tb.N and Tb.Th were much higher at the middle part, while showed the smallest at the medial part. The anterior part demonstrated much higher parameters than the posterior part at the first, second, fifth and sixth layers, respectively, however, the posterior part showed much higher parameters than the anterior part at the third and fourth layers, respectively. The BMD was much higher at the first [(332.66±97.11) mg/cm 3] and sixth [(255.79±45.68) mg/cm 3] layers, while the lowest at the second layer [(255.79±41.06) mg/cm 3]. The BV/TV and Tb.N were much higher at the first layer, with the lowest at the fifth layer. The Tb.Th at the first layer [(0.11±0.03) mm] was much higher than the others, which were similarly lower. The BS/BV, Tb.Sp and Tb.Pf were lower at the first layer and much higher at the medial and lateral parts, while were lower at the middle and anterior parts. The posterior part demonstrated much higher BS/BV, Tb.Sp and Tb.Pf than the anterior part at the first, fifth and sixth layers, respectively. However, the anterior part showed much higher scores than the posterior part at the third and fourth layers, respectively. The ANOVA results showed that the 7 morphological parameters of VOI were not statistically significant amongst the 6 layers ( P>0.05). However, the 6 out of the 7 parameters, i.e. BV/TV, BS/BV, Tb.Th, Tb.N, Tb.Sp and Tb.Pf, were statistically significant amongst the five parts ( P<0.05), while the only parameter of BMD was not statistically significant ( P>0.05). Conclusions:The anatomical distribution characteristics of the trabecular bone of condyle were analyzed by using 3D imaging measurement based on the VOI. The results showed uneven distributions and indicated that the method of dividing the trabecular bone of mandibular condyle into VOI sets, which accorded with its specific anatomical characteristics, was feasible for further reference.

Objective:To investigate the clinical efficacy of mechanical solitaire AB stents thrombectomy combined with intra-arterial thrombolysis in the treatment of patient with acute ischemic stroke.Methods:Fifteen patients with acute ischemic stroke admitted into our hospital from August 2014 to August 2016 were treated with mechanical thrombectomy with solitaire AB stents plus intra-arterial thrombolysis.The National Institutes of Health Stroke Scale score (NIHSS) of all patients were evaluated before and after treatment to compare the clinical efficacy.The prognosis ofpatients between two groups were compared via evaluating modified Rankin score (mRS)and gelasijia coma score (GCS).Results:After mechanical thrombectomy with solitaire AB stents plus intra-arterial thrombolysis treatment,14 patients achieved complete or part recanalization,and 1 patient was terminated treatment due to vital signs instability,and the rate ofrecanalization was 93.3％.The NIHSS score of patients before treatment was 12.93± 4.25,which was much higher than that after treatment (4.33± 1.45,P＜0.05).After follow-up by 3 months,the good mRS scores were obtained in all 18 patients,including 2 patients with mRS score of 2,5 patients with 1,and 8 patients with 0.Additionally,there was no patient with re-obstruction during follow-up period.Conclusion:Mechanical thrombectomy with solitaire AB stents combined with intra-arterial thrombolysis had a good capability and safety in the treatment of patients with acute ischemic stroke.

Objective: To observe the dynamics of antibody response in great gerbils infected with Yersinia pestis in experiment. Method: A total of 211 great gerbils were captured in the southern margin of plague natural focus of Junggar Basin of the Xinjiang Uygur Autonomous Region in 2011. Among them, there were 167 great gerbils without infection of Y. pestis and 44 great gerbils infected by Y.pestis. Y.pestis No. 2504 was employed for this experimental strain, which was strong toxic strain with negativity in the reduction experiment of nitrate. 35 great gerbils without the infection of Y. pestis were divided randomly and averagely into 7 groups including 6 experimental groups and 1 control group. Great gerbils in the 1st to 6th experimental groups were exposed first with 1 × 10⁶-1 × 10¹¹ CFU/ml of bacterial fluid with 10 times of gradient dilution; groin areas of great gerbils in the control group were injected subcutaneously with physiological saline; and the amount of infection was all 1 ml. 17 great gerbils infected with Y. pestis and the first detection of F1-antibody titer in 1∶256-1∶4 096 were grouped according to F1-antibody titer: group 1∶4 096 (n=4), group 1∶2 048 (n=4), group 1∶1 024 (n=3), group 1∶512 (n=3) and group 1∶256 (n=3); and blood in caudal regions was collected in asepsis for the detection of F1-antibody, with a total of 5 times. 9 great gerbils which were selected from the remaining great gerbils infected with Y. pestis and detected F1-antibody negative 2 times were exposed 1×10⁶ CFU/ml of bacterial fluid for the second infection, with the amount of infection being 1 ml. Blood in caudal regions of great gerbils after the first and second infection were collected for the detection of plague F1-antibody on the 3rd, 5th, 7th, 15th, 30th, 60th, 90th and 120th day after infection. Declined regression models for great gerbils' antibodies were established with unary linear regression equation; declined change diagrams for the antibodies were drawn to observe the declined F1-antibody after great gerbils were exposed to Y. pestis. Results: In great gerbils with the first infection of Y. pestis, antibodies were detected in the 1 × 10⁶-1 × 10⁸ CFU/ml of group on the 30th, 15th and 15th day, respectively; the positive rates of antibody were 1/4, 3/4 and 4/5, respectively; the group 1×10⁷ and 1× 10⁸ CFU/ml reached to the highest antibody titer with 1∶256 on the 120th day; antibodies were revealed in the group 1×10⁹, 1×10¹⁰ and 1×10¹¹ CFU/ml from the 5th to 7th day when the seroconversion of all antibodies was observed; group 1×10¹¹ CFU/ml reached to the highest antibody titer on the 120th day with 1∶4 096. In the great gerbils with the second exposure to Y.pestis, positive antibodies were detected on the 3rd day with the positive rate being 2/9; and the highest antibody titer with 1∶2 048 was noted on the 90th day. Unary linear regression equation of declined F1 antibody of great gerbils was y=0.045x- 0.321 (F=115.40, P< 0.001), and the shortest duration for F1-antibody titer declining from 1∶4 096 to 0 was 140 d and the longest duration 200 d. Conclusion Great gerbils infected with the high concentration of Y. pestis fluid show shorter duration in producing F1-antibody, the antibody positive rate is also higher, and the highest antibody titer can reach 1∶4 096. The great gerbils could hold the plague F1 antibodies for a long time which was about 140 to 200 days from the highest titer.

Objective: To construct a three-dimensional (3D) finite element model and analyze the biomechanical characteristics during mandibular second molar mesialization using customized lingual appliances and mini-implant. Methods: One adult student volunteer from The First Affiliated Hospital of Zhengzhou University with lower left first molar extraction was selected. After CT scanning, Mimics, Geomagic, ANSYS were employed to develop a 3D finite element model including customized lingual brackets, stainless steel lingual arch wire, buccal buckles, lower dentition, periodontal ligaments and alveolar bone. Four different loading methods (1. the force of 1.470 N loaded at the lingual side only; 2, 3, 4. the forces of 0.490, 0.735 and 0.980 N loaded at both buccal and lingual sides, respectively.) were included. The initial displacements of the lower second molar and stress distribution in the periodontal ligaments were analyzed. Results: More uniform stress distributions in the periodontal membrane of mandibular left second molar were found when the mesial force were loaded at both buccal and lingual sides than the force loaded at lingual side only. More inclination of the second molar was observed when force loaded at both sides than at lingual side only. With the values of the force increased, the mesial inclination potential of the second molar, the initial movement of the second molar and the stress distribution in the periodontal membrane increased. Under the force of 0.735 N at both buccal and lingual sides, mesially inclined initial displacements of the mandibuar second molar were observed and the stress values of von Mises was in the suitable area. Conclusions Less second molar rotation was found when the force loaded at both buccal and lingual sides than loaded at lingual side only. However, force loaded at both sides would increase the measial inclination potential of the second molar.

BACKGROUND: Biomechanical mechanisms are complex, and previous studiers focus on the stress conduction in the carpus. However, the stress distribution and characteristics of trabecula in the carpus are rarely reported.OBJECTIVE: To investigate the stress distribution and deformation characteristics of the normal lunate through a two-dimensional sagittal finite element model.METHODS: A normal cadaveric lunate sample was scanned with Micro-CT and the central sagittal image was chosen for further finite element analysis (FEA). The chosen image was processed and imported into the finite element analysis software (Ansys 14.0). A two-dimensional sagittal finite element model of the lunate bone was established. Axial pressure was applied to the model with the wrist held in different positions, and nine regions of interests (ROIs) were identified, for which stress and displacement nephograms were created. These included the first principal stress (S1, the maximum stress in a principal plane), the third principal stress (S3, the minimal stress in a principal plane), shear stress (SXY, the component of stress coplanar with a material cross section), von Mises stress (SEQV, yielding begins when the elastic energy of distortion reaches a critical value)and displacement of each ROI (UY, displacement on the vertical plane of the lunate) which were calculated and compared.RESULTS AND CONCLUSION: (1) The stresses on ROIs located in the proximal and volar cortices of the lunate bone were much higher than those in the distal and dorsal cortices. At the proximal lunate, S1 was less than S3; however at the distal lunate, S1 was greater than S3. The ROIs of the distal and proximal ends of the lunate bone received much higher stress than the ROIs of the middle part. As for axial trabecular displacement,both distal and proximal ROIs were compressed by axial pressure. However, the dorsal and the volar parts of the proximal lunate moved in different directions at different wrist postures. Besides, the stress values and magnitudes of displacement were elevated in wrist flexion and extension compared to neutral position.Furthermore, the stress concentration zones (the proximal volar ROI, the proximal dorsal ROI, the distal volar ROI, and the distal dorsal ROI) had different directions of shear stress and displacement in different wrist postures. (2) These results suggest that when stress is loaded on a normal lunate model, four stress concentration zones, the proximal volar ROI, the proximal dorsal ROI, the distal volar ROI, and the distal dorsal ROI are found. The wrist postures can significantly affect the value and distribution of axial stress on the sagittal lunate.

OBJECTIVETo investigate an ideal modeling method of designing 3D mesh scaffold substitutes based on tissue engineering to restore mandibular bone defects. By analyzing the theoretical model from titanium scaffolds fabricated by 3D printing, the feasibility and effectiveness of the proposed methodology were verified.

METHODSBased on the CT scanned data of a subject, the Mimics 15.0 and Geomagic studio 12.0 reverse engineering software were adopted to generate surface model of mandibular bone and the defect area was separated from the 3D model of bone. Then prosthesis was designed via mirror algorithm, in which outer shape was used as the external shape of scaffold. Unigraphics software NX 8.5 was applied on Boolean calculation of subtraction between prosthesis and regular microstructure structure and ANSYS 14.0 software was used to design the inner construction of 3D mesh scaffolds. The topological structure and the geometrical parameters of 3D mesh titanium scaffolds were adjusted according to the aim of optimized structure and maximal strength with minimal weight. The 3D mesh scaffolds solid model through two kinds of computer-aided methods was input into 3D printing equipment to fabricate titanium scaffolds.

RESULTSIndividual scaffolds were designed successfully by two modeling methods. The finite element optimization made 10% decrease of the stress peak and volume decrease of 43%, and the porosity increased to 76.32%. This modeling method was validated by 3D printing titanium scaffold to be feasible and effective.

CONCLUSIONS3D printing technology combined with finite element topology optimization to obtain the ideal mandibular 3D mesh scaffold is feasible and effective.

Feasibility Studies ; Humans ; Mandible ; anatomy & histology ; Porosity ; Printing, Three-Dimensional ; Tissue Engineering ; methods ; Tissue Scaffolds ; Titanium

Objective To construct three-dimensional finite element models with modified crown lengthening surgery and post-core restoration in management of various crown-root fracture types,to investigate the intensity and distribution of stressin models mentioned above,and to compare and analyze the indications of traditional and modified crown lengthening surgeries from the mechanic point of view.Methods Nine three-dimensional finite element models with modified crown lengthening surgery and post-core restoration were established and analyzed by micro-CT scanning technique,dental impression scanner,Mimics 10.0,Geomagic studio 9.0 and ANSYS 14.0 software.The von Mises stress of dentin,periodontal ligament,alveolar bone,post and core,as well as the periodontal ligament area and threshold limit value were calculated and compared with the findings of traditional crown lengthening models which had been published earlierby our research group.Results The yon Mises stress intensity of modified crown lengthening models were:dentin＞post＞core＞alveolar bone＞periodontal ligament.The maximum von Mises stress of dentin(44.37-80.58 MPa) distributed in lingual central shoulder.The periodontal ligament area of the modified crown lengthening surgery was reduced by 6％ to 28％,under the same crown-root fracture conditions,the periodontal ligament area of modified crown lengthening models was larger than that of the traditional crown lengthening models.In modified crown lengthening surgery models,the yon Mises stress of periodontal ligament of B3L1m,B3L2m,B3L3m models exceeded their limit values,however,the yon Mises stress of periodontal ligament of the B2L2c,B2L3c,B3L1c,B3L2c,B3L3c models exceeded their limit values in traditional crown lengthening surgery models.Conclusions The modified crown lengthening surgery conserves more periodontal supporting tissues,which facilitates the long-term survival of teeth.The indication of modified crown lengthening surgery is wider than traditional method.The maxillary central incisors with labial fracture at gingival margin level and with palatal fracture at or below the alveolar crest level are not the indication of the crown lengthening surgery.

Objective:To construct the finite element models of maxillary central incisor and the simu-lations with crown lengthening surgery and post-core restoration in management of different crown-root fracture types, to investigate the stress intensity and distributions of these models mentioned above, and to analyze the indications of crown lengthening from the point of view of mechanics. Methods:An extrac-ted maxillary central incisor and alveolar bone plaster model were scanned by Micro-CT and dental impression scanner ( 3shape D700 ) respectively. Then the 3D finite element models of the maxillary central incisor and 9 simulations with crown lengthening surgery and post-core restoration were construc-ted by Mimics 10. 0, Geomagic studio 9. 0 and ANSYS 14. 0 software. The oblique static force (100 N) was applied to the palatal surface ( the junctional area of the incisal 1/3 and middle 1/3 ) , at 45 degrees to the longitudinal axis, then the von Mises stress of dentin, periodontal ligament, alveolar bone, post and core, as well as the periodontal ligament area, were calculated. Results:A total of 10 high-precision three-dimensional finite element models of maxillary central incisor were established. The von Mises stress of models: post >dentin >alveolar bone >core >periodontal ligament, and the von Mises stress increased linearly with the augmentation of fracture degree ( besides the core) . The periodontal ligament area of the crown lengthening was reduced by 12% to 33%. The von Mises stress of periodontal ligament of the B2L2c, B2L3c, B3L1c, B3L2c, B3L3c models exceeded their threshold limit value, respective-ly. Conclusion: The maxillary central incisors with the labial fracture greater than three-quarter crown length and the palatal fracture deeper than 1 mm below the alveolar crest are not the ideal indications of the crown lengthening surgery.