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.

Growing energy consumption has become a key consideration for hospital infrastructure,while densely-placed data centers in the hospital make things worse.In view of energy saving and environment protection,the authors briefed the inevitable trend and requirements for the hospitals to build environment-friendly data centers,with key details and outcomes covered.

Objective:To evaluate bone formation in human extraction sockets with absorbed surrounding walls augmented with Bio-Oss(R) and Bio-Gide(R) after a 6-month healing period by histologic and histomorphometric analyses.Methods:Six fresh molar tooth extraction sockets in 6 patients who required periodontally compromised moral tooth extraction were included in this study.The six fresh extraction sockets were grafted with Bio-Oss(R) particle covered with Bio-Gide(R).The 2.8 mm × 6.0 mm cylindric bone specimens were taken from the graft sites with aid of stent 6 months after the surgery.Histologic and histomorphometric analyses were performed.Results:The histological results showed Bio-0ss(R) particles were easily distinguished from the newly formed bone,small amounts of new bone were formed among the Bio-Oss(R) particles,large amounts of connective tissue were found.Intimate contact between the newly formed bone and the small part of Bio-Oss(R) particles was present.All the biopsy cylinders measurement demonstrated a high inter-individual variability in the percentage of the bone,connective tissues and BioOss(R) particles.The new bone occupied 11.54％ (0-28.40％) of the total area;the connective tissues were 53.42％ (34.08％-74.59％) and the Bio-Oss(R) particles were 35.04％ (13.92％-50.87％).The percentage of the particles,which were in contact with bone tissues,amounted to 20.13％ (0-48.50％).Conclusion:Sites grafted with Bio-Oss(R) particles covered with Bio-Gide(R) were comprised of connective tissues and small amounts of newly formed bone surrounding the graft particles.

Objective To investigate the mechanism by which hydrogen(H2) helps prevent acute lung injury induced by hyperoxia (HALI) in rats.Methods Thirty male Sprague-Dawley rats were randomly divided into three groups: control group, HALI group and H2 group, with 10 rats in each group.The control group was exposed to air at atmospheric pressure.Rats in HALI and H2 groups were exposed continuously to pure oxygen (100%O2) for 60 hours and during this period, 10 ml/kg of normal saline or H2-saturated normal saline was given every 12 hours by intraperitoneal injection to the HALI and H2 groups, respectively.After treatment, the arterial partial pressure of oxygen was examined and histopathological examination was conducted in each group.Then,RT-qPCR and Western blotting were performed to measure the transcriptional level and protein expression of heme oxygenase 1 (human heme oxygenase 1, HO-1) in rat lung tissue.Results Compared with the HALI group, H2 group showed significantly decreased severity of lung injury and a marked increase in the arterial oxygen saturation.Besides, H2 treatment induced up-regulation of HO-1 mRNA and protein levels.Conclusion The findings suggest that HO-1 may play an important role in the protection against HALI by H2.

SUMMARY In this article , different methods to deal with teeth fractures were discussed by presenting a case of traumatic crown-root fracture in the anterior esthetic zone .The traumatic crown-root fracture is a common problem in clinic .When a fracture line locates in close proximity to or below the alveolar bone crest , the fracture most likely involve the junctional epithelium and the connective tissue attachment .This type of fracture becomes a challenge for restorative dentists because it involves biologic , functional , and es-thetic considerations , especially when the fracture occurs in an esthetic area .In this case , a young patient presented with two fractured upper anterior teeth to the Department of Periodontics , Peking University School and Hospital of Stomatology .After the comprehensive clinical evaluation , the right central incisor was decided to extract for implant therapy and the right lateral incisor was decided to retain by one modified crown lengthening surgery .The most common technique applied to save a retained root is a clinical crown lengthening procedure .However , the aggressive alveolar bone resection of both target and adjacent teeth to reestablish the bone width and periodontal health may compromise functional and esthetic outcomes .To re-duce loss of excessive osseous tissue during osteotomy procedure , the modified crown lengthening of the right lateral incisor was performed , including minor bone resection and root reshaping .Regarding the right central incisor , the retained root was all located below the alveolar bone crest .The extraction and implant procedure , combined with guided bone graft were performed to avoid the damage to neighbor teeth during traditional restorative therapy and to reshape a preferable buccal contour .At the last visit , the patient was recalled with healthy periodontium , normal tooth function and favorable esthetic results .

BACKGROUND:Low back pain in patients with hip osteoarthritis can be relieved to some extent after total hip arthroplasty, indicating the changes in limb line of force have obvious effects on low back pain. OBJECTIVE:To review and analysis the pathological base and biomechanics mechanism of hip-spine syndrome. METHODS: We retrieved PubMed database and China National Knowledge Infrastructure for related articles published from January 1976 to March 2015. The key words were “low back pain, hip-spine syndrome, hip osteoarthritis, total hip replacement, biomechanics, balance parameters” in English and Chinese, respectively. Repeated studies and unrelated articles were excluded. RESULTS AND CONCLUSION:A total of 145 articles were retrieved, and finaly 62 articles were enroled in result analysis. In the pathophysiology, tumor necrosis factor-α, interleukin-1β and matrix metaloproteinases play a significant role in the occurrence and development of hip-spine syndrome. As for the biological biomechanics, the spine-pelvic-lower limb balance compensatory process can be the main mechanical mechanism of hip-spine syndrome, and the balance parameters can provide a basis for the diagnosis, treatment and postoperative evaluation of hip-spine syndrome.

Objective:To compare the bone dimensional changes following tooth extraction alone with extraction plus ridge preservation ( using deproteinized boving bone mineral Bio-Oss? and bioresorbable collagen mambrane Bio-Gide?) in periodontal compromised extraction sockets .Methods: Eighteen molars of sixteen subjects requiring tooth extraction because of periodontal destruction were enrolled in this study .The subjects were assigned to the control group ( extraction alone , EXT) or to the test group ( ridge-preservation procedure with Bio-Oss? and Bio-Gide?, RP) .Parallel periapical X-rays and cone-beam computed tomography ( CBCT ) scans were taken immediately after tooth extraction alone or plus ridge-preservation ( baseline ) and 6 months later .The changes of horizontal ridge width and vertical ridge height were assessed .Results:At the central buccal aspect , the ridge height increased 2 .9 mm in RP group, and reduced 1.0 mm in EXT group.At the distal buccal aspect , the ridge height increased 1.45 mm in RP group, and reduced 1.45 mm in EXT group.The differences between the groups reached statistical significance (P<0.05).The mean ridge width increased at the 1 mm below the crest (the horizontal ridge width was measured with grafting material at three levels at 1 mm below the most coronal aspect of the crest,HW1), which amounted to 3.40 to 5.80 mm in RP group, and 1.45 to 2.90 mm in EXT group.The mean ridge increased at the 4 mm below the crest ( the horizontal ridge width was measured with grafting material at three levels at 4 mm below the most coronal aspect of the crest ,HW4 ) , which amounted to 0.40 to 3.50 mm in RP group, and reduced 0.10 to increased 0.15 mm in EXT group.The test group and the control group were not significantly different (P>0.05).Conclusion:The ridge-preservation approach using Bio-Oss? in combination with Bio-Gide? can significantly increase vertical ridge height and horizontal ridge width after tooth extraction compared with extraction alone in periodontal compromised molars .

Objective To investiGate the distribution of clinical infectious pathoGens and druG resistance status of common bacteria in the Ninth Peopleˊs Hospital Affiliated to medicine School of ShanGhai Jiao TonG University in 20l2. Methods Clinical isolated bacterial strains were collected from the Ninth Peopleˊs Hospital Affiliated to medicine School of ShanGhai Jiao TonG University durinG 20l2. The identification of bacteria and antimicrobial susceptibility were determined by VITEK 2 COMPACT automatic microbioloGy analyzer. The data were analyzed by WHONET 5. 4 software. Results A total of 3456 pathoGenic strains were collected. Of them,Gram positive cocci,Gram neGative bacilli and funGus accounted for 20. 3%,76. 8% and 2. 9% respectively. Methicillin resistant strains in S. aureus( MRSA ) and coaGulase neGative Staphylococcus ( MRCNS)accounted for averaGe of 44. 4% and 85. 5% respectively. No vancomycin and linezolid resistant strains were found. Extended spectrumβ-lactamases strains accounted for 66. 4% and 30. 6% in Escherichia coli ( E. coli)and Klebsiella spp respectively. Strains of E. coli and Klebsiella spp were still hiGhly susceptible to imipenem. Resistance rates of P. aeruGinosa and A. baumannii sppstrains to imipenem were 8. 3% and 58. 4%respectively. Conclusion The major clinical pathoGenic microorGanisms in the Ninth Peopleˊs Hospital Affiliated to medicine School of ShanGhai Jiao TonG University are still Gram neGative bacilli. Baterial resistance is serious. It is important to strenGthen the detection of resistant bacteria in routine work,which is useful for rational use of antimicrobial aGents.

Objective To measure osteoporosis knowledge,belief and self-efficacy of elderly patients with vertebral fracture,and to provide the basis for reducing the incidence of refracture.Methods Totally 72 patients were recruited from an upper first-class hospital in suzhou by using the convenience sampling method.They were measured with the self-designed general information questionnaire,Osteoporosis Knowledge Tests (OKT),Osteopomsis Health Belief scale (OHBS) and Osteoporosis Self-Efficacy Scale (OSES).Results The total score of knowledge was (1 1.06±6.71),the factor scores of risk factors,exercise and calcium intake were(4.13±2.82),(2.90±2.54),(4.04±2.54).The average score of OHBS was (141.82± 13.00).The total score of self-efficacy was (79.49±35.15).Conclusions Health education for elderly patients with vertebral fractures needs to be improved,and to reduce the occurrence of refracture according to different groups of targeted education.

BACKGROUND:Whether the knee is a risk factor for hip fracture is controversial. OBJECTIVE:To investigate the effect and mechanism of knee osteoarthritis in the development of low-energy hip fracture. METHODS:Total y 116 patients with mild traumatic femoral neck fractures and intertrochanteric fractures admitted from October 2014 to January 2015 were enrol ed and retrospectively analyzed. There were 38 males and 78 females. The mean age of onset was (69.2±14.5) years, and al the patients were diagnosed as have simple hip fractures. Anterioposterior and lateral X-ray examination for the hip and knee was performed for each patient. General information, Kel gren-Lawrence grading, scores on Hospital for Special Surgery (HSS), and Western Ontario and McMaster Universities Index of Osteoarthritis were recorded and analyzed. RESULTS AND CONCLUSION:Among the 116 cases, there were 66 cases of femoral neck fractures, 48 of intertrochanteric fractures and 2 of subtrochanteric femoral fractures. According to the Kel gren-Lawrence grading, there were 0 case of grade 0, 21 of grade I, 51 of grade II, 44 of grade III, and 0 of grade IV. Average Kel gren-Lawrence grading was 2.19±0.72 in fractured side and 1.51±0.52 in non-fractured side, and there was a significant difference between the fractured side and non-fractured side (P<0.05). Average score of HSS was 78.4±8.09 in fractured side and 80.2±8.1 in non-fractured side, with statistical difference (P<0.05). These findings indicate that knee osteoarthritis may have some adverse effects in the development of low-energy hip fracture, which can increase the incidence of femoral neck fracture and intertrochanteric fracture.