Effects of core-to-dentin thickness ratio on the biaxial flexural strength,reliability, and fracture mode of bilayered materials of zirconia core (Y-TZP) and veneer indirect composite resins

Statement of problem

Indirect composite resins (ICR) are promising alternatives as veneering materials for zirconia frameworks. The effects of core-to-dentin thickness ratio (C/Dtr) on the mechanical property of bilayered veneer ICR/yttria-tetragonal zirconia polycrystalline (Y-TZP) core disks have not been previously studied.

Marginal bone loss around dental implants with and without microthreads in the neck: A systematic review and meta-analysis

Statement of problem

Whether microthreads in the crestal portion can reduce the amount of marginal bone loss (MBL) around implants has not yet been determined.

Influence of remaining tooth structure and restorative material type on stress distribution in endodontically treated maxillary premolars: A finite element analysis

Statement of problem

How tooth preparation and material type affect the stress distribution of endodontically treated teeth restored with endocrowns remains unclear.

Rapidly increasing rates of hip fracture in Beijing,China

The age‐specific rates of hip fractures have been declining in most countries in the West but a few studies suggest that the rates might be increasing in areas of Asia that are undergoing urbanization. We previously conducted a population‐based study of hip fracture rates in Beijing, China, in 1990 to 1992 that included validation of hip fracture cases. Using a similar approach to validate cases, we estimated the age‐specific hip fracture rates in Beijing, China, for 2002 to 2006. Specifically, we obtained hospital discharge data for hip fractures that were reported to the Beijing Bureau of Public Health. To confirm the diagnoses, Beijing residence, and find cases missed by the public records we checked individual cases in the public health records against medical records in a random sample of Beijing hospitals. The rates from public health data were adjusted for these under‐ and overestimations. We found that between 1990 and 1992 and 2002 and 2006, the adjusted age‐specific rates of hip fracture over age 50 years increased 2.76‐fold (95% confidence interval [CI], 2.68–2.84) in women and 1.61‐fold (95% CI, 1.56–1.66) in men. Over age 70 years, the age‐specific rates increased 3.37‐fold (95% CI, 3.28–3.47) in women and 2.01‐fold (95% CI, 1.95–2.07) in men. From 2002 to 2006, the rates over age 50 years increased 58% in women and 49% in men. We conclude that the rate of hip fracture has been rising very rapidly in Beijing, China. Therefore, the burden of hip fractures may be shifting rapidly from the West to urbanizing areas of the East. © 2012 American Society for Bone and Mineral Research     

ASSOCIATION BETWEEN PEMPHIGUS VULGARIS AND HUMAN LEUKOCYTE ANTIGEN IN HAN NATION OF NORTHEAST CHINA

Objective To investigate the relationship between pemphigus vulgaris （PV） and human leukocyte antigen （HLA） in Han nation of northeast China. Mothods Standard microcytotoxicity test and polymerase chain reaction-sequence specific primers method were used to detect the HLA class Ⅰ antigens and HLA-DRBI and DQBI alleles in 27 patients with PV and results were compared with control group. Gene and phenotype frequencies of HLA-A3, A26（10）, B60（40）, and B13 （27.99%, 48%; 16.11%, 30%; 23.02%, 41%; 16.11%, 30%, respectively） increased significantly in PV group compared with control （1.01%, 2%; 0.5%, 1%; 4.61%, 9%; 5,13%, 10%, respectively）. After P value correction, the difference of A3, A26 （10）, and B60 （40） between the two groups was still significant. The gene frequencies of HLA-DRB 1^＊ 140x （1401, 1404, 1405, 1407, 1408）, DRBI^＊I20x, and DQBI＊0503 alleles in PV group （42.26%, 25.46%, and 23.02%） were significantly higher than control group （5.09%, 7.74%, and 1.89%）. After P value correction, the difference was still significant between the two groups. Collusion PV significantly relates with HLA in PV patients of Han nation of northeast China.     

夏天无生物碱的药理实验研究

本实验证明夏天无生物碱溶液具有延长小白鼠血凝时间;增加犬冠脉血流量和降低血压的作用。故本品对高血压偏瘫,脑血栓,脑血管痉挛,心肌梗塞可能有益。此外,还证明对大白鼠离体肠及子宫均有兴奋作用;对大心脏迷走神经节及颈交感神经节的兴奋传递无阻断作用。     

坐拏草的原植物探讨与在江西的初步调查

坐孥草是收载于《本草纲目》中的一种著名的麻醉用草药,但其原植物种至今仍不清楚,中外学者,说法不一。本文对坐拏草做了一些文献、实地调查、化学和药理初步探索工作。从现有资料来看,坐拏草的原植物可能是以下二种,一为类鸭趾草凤仙花(Impatienscommelinoides Hand-Mazz);另一种为薯莨 Dioscorea cirrhosa Lour.)。但究竟何种为是,则需要作进一步的探讨。     

An implant impression technique involving abutment transition from interim prostheses to definitive restorations in the esthetic zone

This article presents an impression technique involving transfer of the position of implants and the emergence profile of splinted interim prostheses fabricated on nonindexed interim abutments to definitive single crowns fabricated on indexed abutments.     

The Prevalence of Osteoporosis in China,a Nationwide,Multicenter DXA Survey

A number of studies investigated the distribution of BMD values and the prevalence of osteoporosis in China, but their findings varied. Until now, a BMD reference database based on uniform measurements in a large-scale Chinese population has been lacking. A total of 75,321 Chinese adults aged 20 years and older were recruited from seven centers between 2008 and 2018. BMD values at the lumbar spine (L₁–L₄), femoral neck, and total femur were measured by GE Lunar dual-energy X-ray absorptiometry systems. BMD values measured in each center were cross-calibrated by regression equations that were generated by scanning the same European spine phantom 10 times at every center. Cubic and multivariate linear regression were performed to assess associations between BMD values and demographic variables. Sex-specific prevalence of osteoporosis was age-standardized based on the year 2010 national census data for the Chinese population. The sex-specific BMD values at each site were negatively associated with age, positively associated with body mass index levels, and lower in the participants from southwest China than in those from other geographic regions after multivariate adjustment. Furthermore, BMD values at the femoral neck and total femur decreased with the year of BMD measurement. The peak BMD values at the lumbar spine, femoral neck, and total femur were 1.088 g/cm², 0.966 g/cm², and 0.973 g/cm², respectively, for men, and 1.114 g/cm², 0.843 g/cm², and 0.884 g/cm², respectively, for women. The age-standardized prevalence of osteoporosis at the spine or hip was 6.46% and 29.13% for men and women aged 50 years and older, respectively. Currently a total of 10.9 million men and 49.3 million women in China are estimated to have osteoporosis. In our national examination of BMD, we found that BMD values differed by demographic characteristics. We estimated the age-standardize prevalence of osteoporosis in China to be 6.46% and 29.13% respectively, for men and women aged 50 years and older.