拔除阻生智齿中涡轮机法与凿骨劈冠法的比较研究

目的比较涡轮机去骨拔除法(试验组)与凿骨劈冠法(对照组)在拔除中位和低位阻生智齿时的优劣.方法100例(200颗中/低位阻生智齿)均采用自体左右对照,通过掷硬币随机抽样决定试验组和对照组.试验组采用涡轮机拔除法,对照组采用凿骨劈冠拔除法.对手术时间,以及术后疼痛、术后肿胀进行对比观察.结果对于低位阻生齿,涡轮机去骨拔除法手术时间短、术后疼痛及术后肿胀轻.对中位阻生智齿,涡轮机去骨拔除法的手术时间和术后疼痛及肿胀程度大于凿骨劈冠法.结论涡轮机去骨拔除法较凿骨劈冠法在拔除低位阻生齿时具有优势,凿骨劈冠法较涡轮机去骨拔除法在拔除中位阻生智齿时有优势.     

牙科畏惧症发病因素的初步探讨

1988年对920名大学生进行了牙科畏惧症发病因素的流行病学研究,同时采用Corah’s 问卷(CDAS)测量了525人的牙科畏惧水平,结果显示我国大学生的牙科畏惧水平高于国外同类报导。女性的 DAS 均值比男性高,差别有显著性(P<0.001)。随着近20年来我国龋齿发病率的上升,儿童时期的创伤性牙科经历相应增加。因此,这种直接的创伤性经历,牙科环境的影响,来自于家庭或同龄人对牙科的间接经验,以及居民对口腔保健的认识等,是牙科畏惧症的多种发病因素。     

锥面麻花钻横刃廓形及其几何角度分析

横刃对麻花钻的切削性能具有十分显著的影响,这种影响与横刃的廓形及其几何角度分布有关。而横刃的廓形及其几何角度分布又是由钻尖的几何参数决定的.本文在建立起精确的横刃数学模型的基础上,给出了根据任意选定的钻尖几何参数精确、迅速地求解横刃廓形及其几何角度分布的计算方法和公式.通过计算机分析,揭示了横刃廓形及其几何角度分布随钻尖几何参数的变化而变化的规律。     

齿科合金熔炼用钛酸铝坩埚的研制

根据齿科坩埚的工作条件，进行了热震过程分析。试制的钛酸铝坩埚应用于齿科合金熔炼，其抗热震性和抗侵蚀性优于国外进口产品。使用结果表明：钛酸铝是齿科坩埚的最适宜材质。     

基于微立体光刻技术的组织支架的制备

介绍了基于微立体光刻技术制造的三维支架初步模型.由微立体光刻设备制备出了μm级的圆柱阵列式支架和三角孔式支架,整体结构很微小,结构上端为原生代细胞附着区域,下端是细胞培养液的贮液池.支架结构精度较高,可以达到传统快速成型技术不能具备的等级,其微孔之间的孔隙结构达到200μm左右,同时,微孔的数量、大小、分布及形状可人工影响或控制.姜姜     

The dental amalgam issue. A review

Summary Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included.New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included.It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology.     

Synthesis of dental resins using diatomite and nano-sized SiO2 and TiO2

The mechanical properties of dental composites were improved by porous diatomite and nano-sized silica (OX-50) used as co-fillers.The resin composites,filled with silanized OX-50 and silanized diatomit...     

钻削温度测量的试验研究

本文在分析比较国际上有代表性的几种钻削测温方法的基础上,研究了一种新的测温方法,它既能测量钻头切削刃上各点的瞬时温度,又能同时测量工件表面上各点的瞬时温度.通过实验得出了沿切削刃的切削温度分布和切削温度随切削速度、进给量的变化曲线.以及一些有意义的发现。     

诱导大鼠下切牙氟斑牙模型所需饮水氟浓度及时间的筛选

目的通过观察不同浓度加氟饮水对大鼠下切牙釉质表面颜色变化及釉质发育的影响,筛选建立氟斑牙模型的合适实验时间及饮水氟浓度,为进一步研究氟斑牙的发病机理奠定实验基础。方法105只体重为210 g左右的SD雄性大鼠被随机分为4组,对照组15只用去离子水喂养,另外3组分别用含氟25mg/L5、0 mg/L及100 mg/L的氟化钠水喂养6周。分别在51、0、20、304、2 d等不同的时间点对每个大鼠下前牙唇侧面照相,然后每组分别处死一部分大鼠,分离下颌切牙、固定、脱钙并进行HE切片制作。结果正常鼠切牙颜色为橘黄色染色。在50 mg/L和100 mg/L氟化钠组成功地建立了下颌切牙氟斑牙模型,切牙釉质颜色呈现逐渐退变过程,由橘黄色变为浅黄色,白垩色,釉质的成釉细胞成多层排列。100 mg/L氟化钠组比50 mg/L组氟斑牙出现较早且更严重。而对照组和25 mg/L氟化钠组釉质表面颜色正常,成釉细胞排列整齐。结论50 mg/L和100 mg/L氟化钠水能成功的诱导不断生长的鼠切牙氟斑牙的产生。其釉质表面呈现白棕色条纹、白垩色等各种程度的颜色改变。25 mg/L氟化钠水喂养组在为期6周的实验中不产生明显的氟斑牙。     

An in vitro evaluation of novel NHA/zircon plasma coating on 316L stainless steel dental implant

The surface characteristics of an implant that influence the speed and strength of osseointegration include crystal structure and bioactivity. The aim of this study was to evaluate the bioactivity of a novel natural hydroxyapatite/zircon(NHA/zircon) nanobiocomposite coating on 316L stainless steel(SS) dental implants soaking in simulated body fluid. A novel NHA/zircon nanobiocomposite was fabricated with 0(control),5, 10, and 15 wt% of zircon in NHA using ball mill for 1 h. The composite mixture was coated on SS implants using a plasma spray method.Scanning electron microscopy(SEM) was used to evaluate surface morphology, and X-ray diffraction(XRD) was used to analyze phase composition and crystallinity(Xc). Further, calcium ion release was measured to evaluate the coated nanobiocomposite samples. The prepared NHA/zircon coating had a nanoscale morphological structure with a mean crystallite size of 30–40 nm in diameter and a bone-like composition,which is similar to that of the biological apatite of a bone. For the prepared NHA powder, high bioactivity was observed owing to the formation of apatite crystals on its surface. Both minimum crystallinity(Xc=41.1%) and maximum bioactivity occurred in the sample containing 10 wt% of zircon because of minimum Xcand maximum biodegradation of the coating sample.