三种正畸粘结剂粘结性能的体外研究

为比较3种正畸粘接剂在5min和15min的粘接强度,评价去除托槽后的粘接剂残留指数,选取90颗因正畸原因拔除的健康双尖牙,分为6组;第Ⅰ、Ⅳ组用京津釉质粘合剂粘结;第Ⅱ、Ⅴ组用光固化树脂加强型玻璃离子水门汀（RMGICs）粘结,第Ⅲ、Ⅵ组用self-etching primer自酸蚀粘接剂和Transbond XT粘接托槽。第Ⅰ、Ⅱ、Ⅲ组粘结后5min去除托槽。第Ⅳ、Ⅴ、Ⅵ组粘结后15min去除托槽,测量剪切强度并计算粘结剂残留指数（ARI）。结果表明,RMGICs组抗剪切强度最低,京津釉质粘合剂组与自酸蚀粘接剂组抗剪切强度相似。RMGICs组的粘结剂残留指数均值最高,自酸蚀粘接剂组最低。结论：3种正畸粘接剂在粘接5min和15min后均能达到满意的粘接强度。RMGICs抗剪切强度虽稍低,但具有减少釉质脱矿、对环境要求低、去除托槽后牙面更易清洁的优点。     

三种正畸粘结剂与不同材质托槽粘结强度的体外对比研究

目的 对比研究3种正畸粘结剂粘结不同托槽时的抗剪切强度.方法 将60颗因正畸原因拔出的健康双尖牙分为6组,分别用3种不同正畸粘结剂:京津釉质粘合剂、西湖巴尔光固化粘合剂、Transbond XT光敏树脂粘合剂粘结金属托槽和陶瓷托槽,测试其抗剪切强度,并在显微镜下观察各组牙齿表面的粘结剂残留指数(ARI),进行统计学分析.结果 各组间剪切强度有差异(P<0.05),不同粘结剂托槽组合ARI指数有差别(P<0.05).结论 3种粘结剂粘结不同托槽的剪切强度存在差异,但粘结强度均能达到正畸临床需要,西湖巴尔光固化粘结剂与金属托槽粘结强度最高,粘结剂残留较少.     

不同粘接剂对陶瓷托槽与光固化复合树脂修复体粘接效果的实验研究

目的:对四种粘接剂粘接陶瓷托槽与光固化复合树脂修复体的研究,为临床上一定的表面处理方法结合哪种粘接剂系统最理想提供理论依据.方法:将40个树脂面按每组10个随机分为A、B、C、D四组,分别用京津釉质粘接剂、光固化复合树脂粘接剂、3M ESPE粘接剂和BISCO正畸单组分粘接剂粘接,树脂面均喷砂后涂硅烷偶联剂.结果:BISCO粘接剂效果好于3M ESPE粘接剂,而京津釉质和光固化复合树脂粘接剂不能获得正畸有效粘接强度,各组去粘接后破裂率没有显著性差异.结论:BISCO正畸单组分粘接剂和3M ESPE粘接剂可用于陶瓷托槽与光固化复合树脂修复体的粘接.     

不同托槽连接方案在中重度氟斑牙正畸患者中应用效果的对比

目的：探讨不同托槽连接方案在中重度氟斑牙正畸患者中的应用效果。方法收集120例中重度氟斑牙需要正畸的患者,按患者就诊的顺序随机分为4组,4组患者分别采用京津釉质黏合剂、光固化复合树脂直接黏接、釉质局部磨除光固化复合树脂黏接及牙齿表面复合树脂贴面4种不同托槽连接方案,然后比较4种不同托槽连接方案的正畸效果。结果采用京津釉质黏合剂、光固化复合树脂直接黏接、釉质局部磨除光固化复合树脂黏接及牙齿表面复合树脂贴面的4中托槽技术的总托槽脱落率分别为54．13％、17．29％、2．83％、1．42％。牙釉质脱矿程度釉质局部磨除光固化复合树脂黏接组与牙齿表面复合树脂贴面组优于其余两组。结论托槽连接方案光固化复合树脂优于京津釉质黏合剂,而釉质局部磨除光固化复合树脂黏接方案及牙齿表面贴面方案的正畸疗效更明显。     

临床常用粘结剂对铸造纯钛粘结效果的比较

目的：探讨临床常用粘结剂对铸造纯钛的粘结性能,并以Ｎｉ－Ｃｒ合金材料做对照。方法：分别用国产磷酸锌水门汀、京津釉质粘合剂及日本ＦｕｊｉⅠ型玻璃离子粘结剂与两种金属试件粘结并行抗拉及剪切强度测试。结果：铸造纯钛与三种粘结剂的抗拉粘结强度明显高于镍铬合金（Ｐ〈０．０１）,铸造纯钛与镍铬合金对磷酸锌水门汀及釉质粘合剂的剪切粘结强度相差无几（Ｐ〉０．０５）,镍铬合金对ＦｕｊｉⅠ型玻璃离子粘固剂的剪切粘结强     

含氟树脂封闭剂用于预防正畸治疗釉质脱矿临床观察

目的:研究正畸治疗中使用含氟树脂封闭剂预防釉质脱矿的临床效果.方法:将我院牙科近年行正畸治疗60例均分为实验组和对照组,对照组用托槽粘结树脂粘结托槽,实验组先用含氟树脂封闭剂封闭,再用托槽粘结树脂粘结托槽,比较两组治疗1年内托槽脱落率及釉质脱矿程度.结果:实验组和对照组托槽脱落率分别为6.16%及6.39%,组间无显著差异(P>0.05),实验组正畸1年内,釉质脱矿程度评分中(分值越大,釉质脱矿程度越严重),0分及1分均明显高于对照组(P<0.05),2分及3分显著低于对照组(P<0.01).结论:正畸治疗中应用含氟树脂封闭剂封闭牙面,具有理想的预防釉质脱矿的效果,且该种操作方便简单,值得临床推广.     

四种牙本质粘结剂粘结强度的比较研究

目的 比较四种牙本质粘结剂(I-Bond、G-Bond、Xeno V和Clearfil S3 Bond)的粘接强度,为临床上正确选择、合理使用粘接剂提供实验依据.方法 60颗离体前磨牙,随机分为4组,每组15颗.将四种粘结剂分别用于暴露的牙本质表面,修复树脂“冠”,光照固化.用CMT7104型万能材料测试仪测试试件微拉伸和剪切粘结强度,比较四种牙本质粘结剂的粘结强度.结果 四种粘结剂的粘结强度均值依次为Xeno V＞Clearfil S3 Bond＞G-Bond＞I-Bond.其中,I-Bond与G-Bond的粘结强度差异无显著性(P＞0.05)；Xeno V和Clearfil S3 Bond的粘结强度差异亦无显著性(P＞0.05)；而I-Bond和G-Bond的粘结强度明显低于XenoV和Clearfil S3 Bond (P＜0.05).结论 四种牙本质粘结剂中,Xeno V和Clearfil S3 Bond的粘结强度明显高于I-Bond和G-Bond的粘结强度.     

烤瓷贴面的微漏观察

烤瓷贴面具有颜色稳定、美观、抗着色和耐磨损等优点 ,用于前牙美容修复较为广泛。但其固位及对粘固剂的选择值得进一步探讨 [1 ]。本实验的目的是想通过烤瓷贴面修复模型 ,采用几种粘固剂粘结 ,对其边缘微漏进行实验观察 ,以达到对烤瓷贴面修复的进一步了解。1　材料与方法1.1　材料 :将新拔除的无龋坏 30颗上中切牙洁治洗干净 ,分成 3组 ,每组 10个标本。第 1组用 L am lna Bond Set;第 2组用 Cerec Dual粘结 ;第 3组用京津釉质粘固剂粘结。1.2　标本制作 :按临床牙体预备的要求 ,将唇面釉质磨除约 0 .5 m m,边缘呈凹形斜面 ,颈部边缘距…     

两种正畸釉质粘合剂粘接强度的对比研究

目的比较京津牌釉质粘合剂和3M公司的Unite非混合型自凝托槽粘合剂的粘接强度。方法选择因正畸拔除的双尖牙60颗,按粘合剂使用说明书的要求粘接托槽,在粘接5分钟、30分钟和24小时后分别测量两种粘合剂的抗剪切强度和抗张强度,并进行统计分析。结果京津粘合剂5分钟抗剪切强度为4.89±0.31MPa,抗张强度为0.46±0.02MPa;京津粘合剂30分钟抗剪切强度为6.73±0.31MPa,抗张强度为1.42±0.10MPa;京津粘合剂24小时抗剪切强度为12.95±0.31MPa,抗张强度为2.61±0.22MPa;3M粘合剂5分钟抗剪切强度为4.71±0.22MPa,抗张强度为0.48±0.03MPa;3M粘合剂30分钟抗剪切强度为6.86±0.31MPa,抗张强度为1.44±0.16MPa;3M粘合剂24小时抗剪切强度为12.99±0.24MPa,抗张强度为2.56±0.24MPa。结论京津牌釉质粘合剂和3M公司的Unite非混合型自凝托槽粘合剂的粘接强度无不同。     

磷酸预处理釉质对自酸蚀粘接剂粘接力的影响

目的本研究的目的是评估磷酸预酸蚀对自酸蚀粘接系统与釉质粘接剪切力强度的影响。方法根据自酸蚀粘接前是否进行磷酸预酸蚀,将牛牙随机分成2组：①PA组：磷酸预处理（PA）,然后自酸蚀粘接。②SE组：不进行磷酸预处理,直接进行自酸蚀粘接。然后用帕娜碧亚F将合金金属棒粘固在釉质表面上,在试验机上以1mm/min的速度加载,直到脱粘接,记录粘接剪切强度。用独立样本t检验分析数据,取α=0.05。结果联合应用磷酸预酸蚀处理釉质与单独使用自酸蚀粘接系统在粘接剪切强度上的差异有显著不同（P=0.040）。结论结合磷酸预酸蚀比单独应用自酸蚀粘接系统会获得更高的粘接剪切强度。     

三种烤瓷常用粘接材料边缘微渗漏的试验研究

目的比较烤瓷常用粘接材料玻璃离子、聚羧酸锌、EB树脂的边缘渗漏性。方法在30颗健康后牙的釉质和牙本质边缘制备V类洞,随机分为三组,每组10颗。1组使用玻璃离子充填,2组使用聚羧酸锌充填,3组使用EB树脂充填。在100%湿度环境下24h后,分别浸入50%的硝酸银溶液中24h,再用显影液处理10min。样本沿垂直向和颊舌向切开,评价微渗漏情况。结果1组与2组无明显差别,3组与1组、2组差别明显。结论本试验中,EB树脂边缘微渗漏最少,玻璃离子、聚羧酸锌稍大。     

不同类型粘接剂对牙本质粘接强度及耐久性影响的比较研究

目的:比较不同类型粘接剂对牙本质粘接强度及耐久性的影响,从而为临床上选择粘接剂提供参考。方法:选取2019年1月至2020年6月在暨南大学附属深圳市宝安区妇幼保健院口腔科就诊患者50例,其中男25例、女25例,年龄（42.21±8.27）岁。患者因治疗需要拔除50颗完整无龋人离体第三磨牙,采用随机数字表法将其分A、B、...     

The Effect of Composition on the Tableting Indices of Binary Powder Mixtures

ABSTRACT

The purpose of this study was to investigate the effect of the composition of a binary powder mixture on the bonding index, the brittle fracture index, and the strain index, as defined by Hiestand. The studies involved tensile strength and dynamic indentation hardness determinations of square compacts, the solid fractions of which were 0.83. The mixtures were such that both components consolidated by plastic deformation, both components consolidated by brittle fracture, or one component was brittle while the other was plastic. The measured quantities were then used to compute the bonding index, the brittle fracture index, and the strain index. The bonding indices and tensile strengths of the individual plastic materials were greater than those of the individual brittle materials. It was concluded that the bonding indices were linearly related to composition when both materials consolidated by the same mechanism. It was further concluded that the bonding indices were related to compact composition by a second-degree polynomial equation for mixtures with one brittle and one plastic component. This latter relationship was consistent for four pairs of components.     

The Role of Emotional Distress in Drug Use Among Latino Adolescents

The Latino population is one of the fastest growing populations in the country and, relative to other groups, it is a population which must cope with a number of immigration-related stressors. As a result, Latino adolescents may be at special risk for emotional distress and drug use in Latino adolescents. Comorbidity of emotional distress and drug use, the question of whether emotional distress is an antecedent or consequence of drug use, assessment issues, and the relationship between emotional distress, drug use, and high risk behaviors are among the issues addressed. In a survey of primarily 9th and 10th grade immigrant Mexican students, emotional distress was assessed using three abbreviated scales of depression, hostility, and anxiety based on the Hopkins Symptom checklist, a history of suicide attempts was also assessed. Frequency and quantity of ten substances including alcohol, cigarettes, and hard drugs also were assessed. Most types of drug use were significantly correlated with emotional distress and positive history of suicide attempt. A high frequency of alcohol use and inhalant use were associated with emotional distress and a positive history of suicide attempts. Hostility was most strongly correlated with drug use. It is suggested that hostility as well as moderate to high depression symptom levels be considered risk factors for drug use and suicidality in Latino adolescents. It is also recommended that emotional distress be explicitly addressed in the treatment of drug abuse and other problem behaviors in Latino adolescents.     

Bonding mechanisms in tabletting

An investigation has been undertaken to ascertain the role of Van der Waals forces in the formation of tablets. Hamaker constants have been estimated from surface free energy measurements on polymers and materials of pharmaceutical interest. The relationship betwen the Hamaker constants in media of different dielectric constant and the tensile strength of tablets determined by diametral compression in these media has been examined. It was found that the change in Hamaker constant in the different media paralleled the change in tablet tensile strength. It is considered that the bonding of these tablets can be largely accounted for by Van der Waals attractive forces.     

The effect of milling and addition of dry binder on the interparticulate bonding mechanisms in sodium chloride tablets

In sodium chloride compacts, it has been reported that particles within the tablet are held together both by weak distance forces and solid bridges. It was found that milling of the particles or addition of a dry binder appears to reduce the importance of bonding by solid bridges while increasing that of the weak distance forces. Such changes in the surface properties of the particles induced either by milling or addition of a dry binder will not only increase the surface area available for bonding but also increase the number of interparticulate contact points in the compact and, consequently, reduce the stress at each contact point. It is suggested that this reduction in the concentration of stress makes rearrangement of material at the particle surfaces, and thus the development of solid bridges, more difficult. Similarly, it is suggested that milling will increase the surface deformability of asperities on the sodium chloride particles which will also disperse the concentration of stress within the compacts. The changes in the properties of the particle surface also affect fracture propagation during the diametral compression test. If it is assumed that cracks mainly occur between particles, milling will probably increase the distance the fractures will run.     

Indices of tableting performance and application of percolation theory to powder compaction

The mechanical properties, tensile strength and identation hardness of compacts of different excipients with brittle or plastic characteristics are discussed, using two approaches on powder compaction. The first one, Leuenberger's exponential model extended later by percolation theory, is used to determine the compactibility, the compressibility and the characteristic relative density () of the compacts. Characteristic relative density is the point when the first stable pharmaceutical compact is obtained. The second approach characterises the compact properties by using dimensionless indices, Hiestand's indices, which give insight about relative tableting performance of materials. This study showed that the two approaches are complementary. In fact, when the relative density of excipients with plastic behaviour is increased, the bonding index increases. This evolution may be interpreted by the percolation theory for the region of dense compacts by the assumption of a difference in the percolation thresholds , and obserbed from indentation hardness and tensile strength measurements respectively. The appearance of these transitions by ‘out-of-die’ measurements of the compaction properties of the studied excipients is similar to that observed earlier by the application of percolation theory to ‘in process’ compaction measurements.     

Effect of particle size and compaction load on interparticulate bonding structure for some pharmaceutical materials studied by compaction and strength characterisation in butanol

The remaining tensile strength (the strength of tablets in 1-butanol divided by the strength in air) was used as a simplified measure of bonding by solid bridges and/or mechanical interlocking. The remaining tensile strength is believed to provide information about interparticulate bonding structure. Weak distance forces appeared to play an important role in the bonding of all compacts. Bonding by mechanical interlocking has been suggested as a possible bonding mechanism for dicalcium phosphate dihydrate and microcrystalline cellulose. Solid bridges develop during compaction of sodium chloride tablets. Sodium bicarbonate and sodium chloride have similar chemical structures and volume reduction behaviour. However, due to the more complex intraparticulate chemical structure, solid bridges probably do not develop to a large extent in sodium bicarbonate compacts. Weak distance forces are probably the most important bonding mechanism for lactose and sucrose. Decreasing particle size and increasing compaction load appear to decrease bonding by mechanical interlocking in materials where this type of bond is possible. Increasing particle size and compaction load in sodium chloride compacts facilitates the development of solid bridges. However, the compaction load and particle size do not seem to have any major effect on the bonding structure in lactose and sucrose compacts.     

The impact of early parenting bonding on young adults' Internet addiction,through the mediation effects of negative relating to others and sadness

The aim of the present study is the investigation of the potential role of negative relating to others, perceived loneliness, sadness, and anxiety, as mediators of the association between early parental bonding and adult Internet Addiction (IA). The factorial structure of the Internet Addiction Test (IAT) and the prevalence rates of it in a Greek sample will also be investigated. A total of 774 participants were recruited from a Technological Education Institute (mean age = 20.2, SD = 2.8) and from high school technical schools (mean age = 19.9, SD = 7.4). The IAT was used to measure the degree of problematic Internet use behaviors; the Parental Bonding Instrument was used to assess one's recalled parenting experiences during the first 16 years of life; the shortened Person's Relating to Others Questionnaire was used to assess one's negative (i.e. maladaptive) relating to others (NRO). Both exploratory and confirmatory factor analyses confirmed the three-factor structure of the IAT. Only 1.0% of the sample was severely addicted to the Internet. The mediated effects of only the NRO and sadness were confirmed. Negative relating to others was found to fully mediate the effect of both the father's optimal parenting and affectionless control on IA, whereas sadness was found to fully mediate the effect of the mother's optimal parenting on IA. Overall, the results suggest that parenting style has an indirect impact on IA, through the mediating role of negative relating to others or sadness in later life. Both family-based and individual-based prevention and intervention efforts may reduce the incidence of IA.     

人体脚长、脚掌宽与身高相关关系的研究

对489名男女青年进行了脚长、脚掌宽与身高的测量,并记录相关数据,将测量数据输入计算机中进行回归分析,得出脚长、脚掌宽推测身高的直线回归方程,利用脚长推测身高:男性:y=93.55+3.26x,女性:y=130.53+1.41x;利用脚掌宽推测身高:男性:y=130.79+4.18x,女性:y=137.99+2.72x。结果表明,人体脚长、脚掌宽与身高存在一定的线性关系。