纳米磷酸三钙复合人工骨的Ames致突变试验

目的 从基因角度探讨纳米磷酸三钙／胶原复合人工骨的遗传毒理学特性。以了解此复合人工骨的生物相容性，为其在骨缺损修复领域的临床应用提供依据。方法 将纳米级磷酸三钙（β－TCP）同胶原复合，制成纳米β－TCP／胶原复合人工骨，并制备浸提液，采用Ames致突变试验，以生理盐水为阴性对照，测试其对鼠伤寒沙门菌的致突变比值（MR＝实验组回变菌落数Rt／阴性对照组回变菌落数Rc）。结果 阳性对照组各菌株回变菌落平均数均超过其相应阴性对照组回变菌落平均数的二倍以上（MRp＞2)，此复合人工骨的浸提液各剂量组对鼠伤寒沙门菌的致突变比值MR均小于2。结论 纳米磷酸三钙／胶原复合人工骨不会引起鼠伤寒沙门菌的回复突变数增加，提示此人工骨不会引起基因突变。     

改良人工唾液对鼻咽癌放疗患者唾液pH值和缓冲能力的影响

目的:探讨改良人工唾液对鼻咽癌放疗患者全唾液pH值和缓冲能力的影响。方法:选择8例因鼻咽癌放疗并伴有口干症的患者为受试者,收集唾液时间为上午9点至11点。用改良人工唾液含漱1 m in,收集基线时及含漱后2分钟静止性及刺激性全唾液,对含漱前后静止性唾液的pH值和含漱前后刺激性唾液的缓冲能力进行测定。结果:经改良人工唾液含漱后,患者静止性全唾液pH值较含漱前为高,经统计学检验其差异具有显著性(P<0.05);患者刺激性全唾液缓冲能力大于含漱前,经统计学检验其差异具有高度显著性意义(P<0.01)。结论:改良人工唾液具有改善鼻咽癌放疗患者全唾液pH值和缓冲能力的作用。     

The effect of curing with plasma light on the shrinkage of dental restorative materials

Commercially available light activated dental composites were used in this study to compare the shrinkage following curing with plasma light (Apollo95E, DMDS) and a convention halogen dental curing light (Prismetics Lite II, Dentsply). Polymerization shrinkage was determined by measuring the strain in one dimension by means of a contacting transducer. The percentage linear shrinkage were: Spectrum H = 1.84 + 0.31, P = 1.49 + 0.35*; Ana aesthetic H = 2.04 + 0.38, P = 1.85 + 0.27; Esthet.x H = 1.66 + 0.28, P = 1.69 + 0.25; Dyract AP H = 2.39 + 0.33, P = 2.18 + 0.35*; Apollo Restore H = 1.88 + 0.36, P = 1.42 + 0.33*; Surefil H = 0.88 + 0.28, P = 0.99 + 0.30 where * = significantly different, t-test at P < 0.05. The results suggested that there was less shrinkage when curing some, but not all, materials using the plasma light, although this could be attributed to a reduced level of polymerization.     

氯化镧对人牙釉质人工龋的影响──扫描电镜、电子探针分析

借助体外人工龋方法从形态和内部结构变化上探讨了氯化镧（Ｌａ３＋）对人牙釉质龋的影响。磨片光镜下显示Ｌａ３＋预处理阻抑龋病发展的作用不如氟化钠（Ｆ－），但Ｌａ３＋与Ｆ－先后预处理能明显减轻龋损程度。扫描电镜观察发现Ｌａ３＋及Ｆ－预处理均能在牙面形成覆盖物，但以Ｌａ３＋与Ｆ－先后预处理产生的覆盖物较致密且与牙面结合较紧密。电子探针分析显示Ｌａ３＋处理后釉质表层内钙（Ｃａ２＋）含量明显减少，而Ｌａ３＋显著增加，表明Ｌａ３＋能与Ｃａ２＋发生离子交换反应而进入釉质。这种牙面覆盖物的形成及Ｌａ３＋－Ｃａ２＋交换反应可能是Ｌａ３＋预处理能防龋的关键之一。     

三种品牌人工牙在全口义齿修复中的性能比较

目的 观察三种品牌人工牙制作全口义齿修复7－8年后的磨耗及He关系变化。方法 选择103例全口义齿修复患者，让其自选三种品牌人工牙之一作全口义齿修复，7－8年后复查人工牙He面磨耗程度，颌位和He关系的变化，义齿固位情况及咀嚼效能的自我评价。结果 三种品牌人工牙所作全口义齿7－8年后的He磨耗，义齿固位经秩和统计分析，Ivoclar牌人工牙与ODI和Bayer两种品牌相比差异有显著性（P＜0.05)，ODI与Bayer比较差异无显著性（P＞0.05)。结论 使用 优质的塑脂人工牙作全口义齿修复，能延长全口义齿发挥最佳咀嚼效能时间。     

A Technique for Improved Maxillary Record Base Adaptation Through Controlled Polymerization of Light-Activated Dental Resins

A technique for the fabrication of light-activated maxillary record bases is described. The use of a segmental polymerization process provides improved palatal adaptation by minimizing the effects of polymerization shrinkage. Utilization of this technique results in record bases that are well adapted to the corresponding master casts.     

Effect of desensitising toothpastes on dentinal tubule occlusion: A dentine permeability measurement and SEM in vitro study

Objectives

The purpose of this study was to evaluate the in vitro effectiveness of a new bioglass-containing and two commercial desensitising toothpastes on dentinal tubule occlusion after citric acid challenge or artificial saliva (AS) immersion.

Methods

One hundred dentin discs from human third molars were used. Specimens were randomly divided into five groups (n = 20), Group 1: EDTA-treated dentin; Group 2: brushing with distilled water; Group 3: brushing with Novamin; Group 4: brushing with Sensodyne Freshmint; Group 5: brushing with Colgate Sensitive. In each group, samples were then equally split into two subgroups (n = 10) to test two post-treatments: 6% citric acid challenge or 24 h immersion in artificial saliva. Dentine permeability of each specimen was measured before and after each treatment using a hydrostatic device working at 20 cm H₂O pressure. Data were analysed by two-way repeated measures ANOVA to determine if there were any significant differences within or between groups. Dentine morphology and surface deposits were observed by SEM.

Results

All three desensitising toothpastes significantly reduced dentine permeability and created precipitates on the treated dentine surfaces. Moreover, the reductions in dentine permeability showed partial recovery after a citric acid and artificial saliva immersion. Sensodyne showed significant resistant to acid attack and Novamin exhibited the lowest permeability after artificial saliva immersion for 24 h.

Conclusions

The application of the three toothpastes resulted in effective dentinal tubule occlusion. However, the new bioglass-containing toothpaste (Novamin) represented excellent occlusion effects after brushing treatment and AS immersion, while Sensodyne demonstrated more reduction in permeability when citric acid challenged.     

聚氨酯凝胶预聚物对传统树脂基质体积收缩的影响及对其综合性能的改善作用

合成一种光反应性聚氨酯（PU）凝胶预聚物IBGBMA,并探讨其对传统树脂基质体积收缩和机械性能的影响。     

人工智能对基层影像医生筛查肺结节的辅助价值

目的探讨基层影像医生结合人工智能辅助诊断系统对厚层CT中4 mm以上结节检出效能的差异。方法前瞻性收集2019年1月1日至1月31日在我院接受常规胸部CT检查的118例患者并进行层厚5 mm骨算法重建,由两位十年以上诊断经验的主治医师和一位十五年以上诊断经验的副主任医师借助人工智能软件(InferRead CT_Lung 6.0,Infervision,Beijing,推想科技)确定肺结节金标准。由基层医院两位主治医师对CT图像进行独立阅片,记录结节的数量、位置、长径和标记时间,两周后再次借助AI对同一批图像进行阅片,计算医生独立阅片(A组)及借助AI(B组)两种情况下的结节检测敏感度、假阳性率,同时比较两种情况标记时间。结果A组和B组对于4 mm以上肺结节检出总数分别为172和293个,其中真阳性结节数分别为112和171个,假阳性结节数分别为60和122个。B组肺结节的检测敏感度显著高于A组(P0.01)。A、B两组医生肺结节平均检测时间比较,差异有统计学意义(P0.05)。结论 AI对于肺结节检出具有较好的辅助能力,借助AI辅助诊断系统的基层影像医生对厚层图像4 mm以上肺结节的标记时间更短,结节诊断敏感度更高。     

罕见病智能知识服务平台的设计

随着信息技术的发展和信息传播方式的日益便捷,借助智能知识服务平台增加患者及其家属、基层医生和专科医生等对罕见病的熟悉程度并提高罕见病识别能力和知识水平成为切实可行的措施。本研究在分析罕见病患者及其家属、医务人员和医药科研人员等罕见病智能知识服务平台主要用户知识需求的基础上,设计了罕见病智能知识服务平台的技术架构,展现了数据集成层、知识层、功能层、表现层和用户层的主要内容;明确了罕见病智能知识服务系统的主要功能,包括综合资讯、知识地图、信息查询、智能服务、辅助登记、交流互动和健康管理等,并设计了相应的功能模块,可为有效满足信息时代下不同用户多样化的知识需求、提高公众对罕见病的认知、促进罕见病智能服务体系的建设、减少罕见病研究信息孤岛和数据盲点、充分发挥信息化整体效应和规模效应奠定良好基础。