Na18F PET/CT用于恶性肿瘤骨转移诊断的Meta分析

目的Na^18F是一种主要用于诊断成骨反应活性程度增加的骨疾病的正电子计算机断层显像药物,肿瘤骨转移的诊断是其重要的适应症之一。本研究旨在对Na18FPET/CT用于肿瘤骨转移诊断的诊断效果进行系统评价。方法对2000年1月1日至2018年12月31日公开发表的Na^18F PET/CT诊断骨转移的文献用计算机检索中英文数据库,根据纳入与排除标准筛选出符合要求的文献,进行数据提取和质量评价,采用Stata 12.00软件进行Meta分析。结果共35篇文献纳入本研究,中文文献9篇,英文文献26篇。Meta分析结果显示:①Na^18F PET/CT诊断骨转移的灵敏度、特异性、阳性似然比、阴性似然比、曲线下面积,以患者为计算基础时分别为0.97、0.93、14.5、0.03和0.99;以病灶为计算基础时分别为0.96、0.88、8.3、0.05和0.98;②对不同原发灶(肺癌、乳腺癌及前列腺癌)的ROC曲线比较可知:三种不同的原发灶之间均无显著性差异;③所有纳入本研究的文献未见有使用Na18F后出现不良反应的报道。结论无论以患者还是以病灶为基础,Na^18F PET/CT诊断骨转移的效能均很好,Na^18F PET/CT对肺癌、乳腺癌和前列腺癌骨转移的诊断效能无明显差异,未见使用Na18F后出现不良反应的报道。     

The effectiveness of respiratory protection worn by communities to protect from volcanic ash inhalation. Part II: Total inward leakage tests

Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of respiratory protection (RP), most commonly surgical masks. However, there is currently no evidence on how effective such masks are in protecting wearers from volcanic ash. In Part I of this study (Mueller et al., 2018), we assessed the filtration efficiency (FE) of 17 materials from different forms of RP against volcanic ash and a surrogate, low-toxicity dust, Aloxite. Based on those results, we now present the findings from a volunteer simulation study to test the effect of facial fit through assessment of Total Inward Leakage (TIL).Four different disposable RP types that demonstrated very high median FE (≥96% for Aloxite; ≥89% for volcanic ash) were tested without provision of training on fit. These were an industry-certified mask (N95-equiv.); a surgical mask from Japan designed to filter PM_2.5; a flat-fold basic mask from Indonesia; and a standard surgical mask from Mexico, which was also tested with an added medical bandage on top, as an additional intervention to improve fit.Ten volunteers (6 female, 4 male) were recruited. Each RP type was worn by volunteers under two different conditions simulating cleaning-up activities during/after volcanic ashfall. Each activity lasted 10?min and two repeats were completed for each RP type per activity. Dust (as PM_2.5) concentration inside and outside the mask was measured with two TSI SidePak aerosol monitors (Models AM510 and AM520, TSI, Minnesota, USA) to calculate TIL. A questionnaire was administered after each test to collect perceptions of fit, comfort, protection and breathability.The best-performing RP type, across both activities, was the industry-certified N95-equiv. mask with 9% mean TIL. The standard surgical mask and the basic flat-fold mask both performed worst (35% TIL). With the additional bandage intervention, the surgical mask mean TIL improved to 24%. The PM_2.5 surgical mask performed similarly, with 22% TIL. The N95-equiv. mask was perceived to provide the best protection, but was also perceived as being uncomfortable and more difficult to breathe through.This study provides a first objective evidence base for the effectiveness of a selection of RP types typically worn around the world during volcanic crises. The findings will help agencies to make informed decisions on the procurement and distribution of RP in future eruptions.     

HAB/DBP 复合物修复骨缺损的实验研究

目的：研究羟基磷灰石人工骨（HAB）/异体脱矿骨粉（DBP）复合物修复骨缺损的效果，以期获得一种既具有传导性又具有骨诱导性的复合材料。方法：将HAB/DBP复合物、HAB、异体脱矿骨(DMB)植入兔桡骨中段骨缺损处，设置空白对照，在2、4、8、12周分别取材，观察新骨形成及骨缺损修复情况。结果：HAB/DBP组、DMB组2周时可见骨断端附近有大量软骨细胞聚集，并有少量基质形成。4周时，大量软骨细胞及少量骨小架。8周时，见大量骨小梁和层板状骨形成。12周见层板成熟骨组织和哈佛系统形成。其成骨能力及新骨生成量明显高于HAB组及空白组。结论：HAB/DBP复合物为一种既具有骨传导性又具有骨诱导性的骨缺损修复材料，具有与DMB同样的诱导骨生成的能力，可能成为一种具有临床应用前景的骨缺损及修复材料。     

鼠哺乳期二(噁)英暴露对子代牙槽骨生长发育的影响

目的 研究鼠哺乳期二(噁)英类物质2,3,7,8-四氯二苯对二(噁)英暴露对大鼠仔鼠牙槽骨生长发育的影响.方法 60天龄2,3,7,8-四氯二苯对二(噁)英暴露组和对照组仔大鼠被处死,将其带有磨牙的上颌骨行树脂包埋,制备硬组织磨片并在荧光显微镜下观察,对两实验组牙槽骨的组织形态、荧光标记情况及组织形态计量学参数进行比较.结果 与对照组相比,二(噁)英暴露组牙槽骨骨小梁结构较为疏松,荧光标记较紊乱.实验组与对照组骨小梁宽度分别为(52.5±5.2)μm及(59.4±6.6)μm,二者差异有统计学意义(P<0.05);骨小梁数目分别为(3.27±0.23)mm-1及(3.75±0.29)mm-1,差异有统计学意义(P<0.01);骨小梁分离度分别为(217.3±37.6)μm及(177.6±33.8)μm,差异有统计学意义(P<0.05);矿化沉积率分别为(0.68±0.08)μm/d及(0.95±0.12)μm/d,差异亦有统计学意义(P<0.05).结论 二(噁)英类物质哺乳期暴露显著降低了大鼠仔鼠牙槽骨的质、量,并影响其空间构型.     

Correlation of mandibular bone quality with neurosensory disturbance after sagittal split ramus osteotomy

Our aim was to find out whether the quality of bone around the inferior alveolar nerve is correlated with neurosensory disturbance to the nerve after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Computed tomograms (CT) were taken of 35 patients with mandibular prognathism and 35 without. To assess the density of bone around the inferior alveolar nerve, the width of the buccal cortical bone in the mandibular second molar regions was measured on CT. The Hounsfield units (HU) in the same regions were also measured. The number of HU in the mandible around the second molar regions was significantly higher (p < 0.01) in those with neurosensory disturbance (p < 0.01). The quality of bone measured by HU is associated with an increased risk of neurosensory disturbance, but the width of buccal bone is not.     

玻璃离子水门汀与银汞粘接的剪切力测试

探讨了玻璃离子水门汀增强银汞充填体与牙体之间的粘结作用。取新鲜离体人磨牙制成3mm厚的牙块,在其中央制备直径3mm的圆柱形洞,分别以玻璃离子、银汞粘结剂涂于洞壁,再充填银汞合金,另设空白对照组。两周后测各组的剪切力并作统计学分析。结果表明:玻璃离子与银汞粘结剂组的剪切力比空白对照组大,并有显著差异;说明玻璃离子与银汞粘结剂均有相似的增强银汞修复体与牙体之间粘结力的作用。     

Replacement of a fixed partial denture secondary to abutment fracture

BACKGROUND: The authors present a case that demonstrates the efficient replacement of a fixed prosthesis after a patient's abutment tooth fractured and required extraction. The fractured tooth had a local infection, and the maxillary bone was low-density and limited in height. CASE DESCRIPTION: The authors removed the tooth and grafted the site with particulate bone, while concurrently placing two implants in the edentulous region. After four months, they placed one additional implant and secured a fixed provisional prosthesis within one week. CLINICAL IMPLICATIONS: The patient wanted to minimize the time that she would have to be without a fixed prosthesis. The authors met her expectations by using an accelerated treatment plan.     

Magnitude and direction of mechanical stress at the osseointegrated interface of the microthread implant

Background: The mechanism by which the microthread implant preserves peri‐implant crestal bone is not known. The objective of this research is to assess the effect of microthreads on the magnitude and direction of the stress at the bone–implant interface using finite element analysis modeling. Methods: Three‐dimensional finite element models representing the microthreaded implant (microthread model) and smooth surface implant (smooth model) installed in the mandibular premolar region were created based on microscopic and computed tomography images. The mesh size was determined based on convergence tests. Average maximum bite force of adults was used with four loading angles on the occlusal surface of the prosthesis. Results: Regardless of the loading angle, principal stresses at the bone–implant interface of the microthread model were always perpendicular to the lower flank of each microthread. In the smooth model, stresses were affected by the loading angle and directed obliquely to the smooth interface, resulting in higher shear stress. The interfacial stresses decreased gradually in the apical direction in both models but with wavy pattern in the microthread model and smooth curve for the smooth model. Although peak principal stress values were higher around the microthread implant, peri‐implant bone volume exhibiting a high strain level >4,000 μ was smaller around the microthread implant compared to the smooth implant. Conclusion: Stress‐transferring mechanism at the bone–implant interface characterized by the direction and profile of interfacial stresses, which leads to more compressive and less shear stress, may clarify the biomechanical aspect of microthread dental implants.     

牙种植修复与骨密度的临床应用研究

目的：探讨颌骨骨密度在牙种植修复中的作用及意义，并分析种植体松动度与颌骨骨密度及牙龈指数的关系。方法：对49例患者，66颗缺牙进行牙体种植修复，修复前后分别进行临床及X线检查。结果：49例患者中有48例骨密度值在150～80范围内，占牙种植数的72％，松动度为0度者占95％．牙龈指数为0度者占93％；骨密度与松动度呈负相关，而牙龈指数与松动度呈正相关。结论：骨密度与种植修复体的成功与否密切相关，以X线定期检查是必要的。     

小鼠骨髓细胞和脾细胞诱导形成破骨细胞潜能的比较

目的在体外破骨细胞分化因子(RANKL)和巨噬细胞集落刺激因子(M-CSF)联合应用的情况下,比较小鼠骨髓细胞和脾细胞形成破骨细胞的能力。方法选用小鼠M-CSF依赖性非附着性骨髓细胞和脾细胞,以不同的细胞密度在含有25ng/mlsM-CSF和30ng/mlsRANKL的(-MEM培养液中培养5、9天后,计数形成的抗酒石酸酸性磷酸酶染色(TRAP)阳性多核细胞的数目和骨吸收面积。结果脾细胞形成的破骨样细胞与骨髓形成的细胞形态与功能均无明显差异,但所需的细胞密度为骨髓细胞的10~20倍。结论在特殊情况下,脾细胞可替代骨髓细胞进行体外破骨细胞实验,但培养条件应适当调整。