氧化锆表面不同处理方式对锆瓷与饰瓷结合强度的影响

目的：探讨不同方式处理对氧化锆陶瓷与饰瓷结合强度的影响。方法：制作40个氧化锆瓷块、10个镍铬合金片，并按照表面处理方法分为5组，即喷砂组(A组)、结合瓷组(B组)、热酸蚀组(C组)、氧化锆空白对照组(D组)、镍铬烤瓷对照组(E组)。5组试件处理完成后，采用粉浆涂塑法烧结大小为4 mm×4 mm×2 mm的饰瓷。通过万能试验机对所有试件进行剪切强度测试，每组随机抽取一个样本在电子显微镜下进行界面破坏形貌分析。结果：剪切强度结果显示：与D组相比，A组和B组剪切强度差异均无统计学意义(均P>0.05)，且二者均显著小于E组(均P<0.05)；C组剪切强度值显著高于D组、A组和B组(均P<0.05)，但与E组相比差异无统计学意义(P>0.05)。结论：喷砂及烧结的结合瓷层对于增强锆瓷与饰瓷的结合强度无显著作用，热酸蚀可以显著增强锆瓷与饰瓷的结合强度。     

Effect of Dietary Simulating Solvents on the Mechanical Properties of Provisional Restorative Materials-An In Vitro Study

Conservation of natural tooth structure precipitated the emergence of resin-retained fixed partial dentures. The weakest link in this modality is the bond between resin cement and alloy of the retainer. Various alloy surface treatment have been recommended to improve alloy–resin bond. This in vitro study was carried out to observe changes in the Nickel–Chromium alloy (Wiron 99, Bego) surface following sandblasting or electrolytic etching treatment by scanning electron microscope (SEM) and to evaluate the shear bond strength of a resin luting cement bonded to the surface treated alloy. 80 alloy blocks were cast and divided into four groups of 20 each. In groups-A & B, the test surfaces were treated by sandblasting with 50 and 250 μm sized aluminium oxide particles respectively. In groups-C & D, the test surfaces were first treated by sandblasting with 50 and 250 μm sized aluminium oxide particles respectively followed by electrolytic etching. Test surfaces were observed under SEM at 1,000× magnification. Two alloy blocks of each group were luted together by a resin luting cement (Rely X, 3M) and their shear bond strength was tested. The mean shear bond strength in MPa of groups-A to D were 6.44 (±0.74), 8.18 (±0.51), 14.45 (±0.59) and 17.43 (±1.20) respectively. Group-D showed bond strength that is more than clinically acceptable bond strength. It is recommended that before luting resin-retained fixed partial dentures, the fitting surface of the retainer should be electrolytically etched to achieve adequate micromechanical retention.     

胶束毛细管电泳法检测IL-12的含量

目的 建立胶束毛细管电泳法鉴定白介素-12（IL-12）、检测其含量并分析IL-12去折叠的过程。方法 以50 ?m i.d.×48.5 cm未涂层毛细管为色谱分离柱，分析影响IL-12分离效果的因素并建立IL-12标准曲线；将IL-12与抗IL-12抗体混匀液在38 ℃水浴槽中孵育，40 min后在相同条件下进行毛细管电泳，将其与IL-12、抗IL-12抗体的电泳结果比较以鉴定IL-12；将IL-12与DTT在60 ℃水浴槽中孵育不同时间，并研究IL-12在不同状态下的电泳结果分析IL-12去折叠的过程。结果 建立了以含30 mmol/L十二烷基硫酸钠（SDS）的硼酸盐（pH=9.3，80 mmol/L）为缓冲液的胶束毛细管电泳在线扫集法；IL-12的峰面积与质量浓度具有良好的线性关系，线性相关系数为0.9991，线性范围为2~120 ng/L；随着IL-12与DTT孵育时间的延长，IL-12的二硫键逐渐被打开，图谱中可显示蛋白峰随之发生的变化。结论 毛细管电泳法操作简单、灵敏度高，这为今后在肿瘤等疾病中快速检测IL-12的含量以及分析其含量变化的原因提供理论依据。     

镍铬钛烤瓷金瓷剪切结合强度的测试

目的通过对自制镍铬钛（Ni-Cr-Ti）烤瓷合金与Vita常用瓷的剪切结合强度的测试,探讨镍铬烤瓷合金添加钛、混合稀土金属以及不含铍（Be）对金瓷结合性能的影响。方法使用中国科学院金属研究所研制的镍铬钛烤瓷合金,共分3个试验组,各组成分略有差异,以HI BOND非贵金属烤瓷合金为对照组,所有试件在万能试验机上采用剪切力试验测试金瓷分离时的载荷。结果3个实验组剪切强度值依次为R1组（28.1864±2.80702）MPa,R2组（26.1585±3.38148）MPa,R3组（25.1663±3.12508）MPa,对照组为（29.1436±3.28302）MPa。通过单向方差分析和SNK检验,各组之间差异均无显著性意义（P〉0.05）。结论自制镍铬钛烤瓷合金的金瓷结合良好,剪切结合强度可以达到临床应用的要求。     

Bond strength test: role of operator skill

BACKGROUND: Test method, substrate material and operator variability are factors known to affect bond strength test outcomes. The aim of this study was to determine if, with increasing experience, individual operator skill in material handling influenced microshear bond strength outcomes. METHODS: This retrospective study used data collected from six preliminary tests carried out successively on enamel microshear bond strength for two adhesives: Clearfil SE Bond (Kuraray) and Adper Single Bond 2 (3M ESPE) by one operator. Mean and median microshear bond strength values, standard deviations and coefficients of variation for each adhesive test group were calculated and assessed. RESULTS: A gradual increase in mean microshear bond strengths, a decrease in standard deviations and coefficients of variation over time for both adhesives and a progressively more uniform distribution of microshear bond strength results recorded in individual test sets was observed. The results suggest an improvement in bonding reliability as experience is gained. CONCLUSIONS: Operator skill in material handling appears to play a critical role in determining the outcome of bond strength testing. This same skill is probably relevant when using an adhesive for the first time clinically. It is important that clinicians become familiar with new adhesives in order to achieve optimal outcomes.     

脱敏剂处理后牙本质粘结界面形态及粘结强度研究

目的 探讨3种脱敏剂对牙本质粘结剂粘结强度和微观形态的影响。方法 12颗完整无龋的人第三磨牙,去除咬合面釉质,随机分为4组(n=3):A组(空白)、B组(Oravive)、C组(GC护牙素)、D组(氟化钠甘油)。A组不做处理,B、C、D组分别使用相应脱敏剂在牙本质表面处理,全部样本Prime&Bond NT树脂粘结剂粘结,复合树脂修复厚约4~5 mm,慢速切割机制成1.0 mm×1.0 mm×8.0 mm长方体试样,微拉伸测试仪测试粘结强度并进行统计学分析。体视显微镜下观察断裂模式,每组随机选取3个断裂前样本扫描电镜观察。结果 粘结强度A组最高[(24.45±4.57)Mpa],与其它三组有统计学差异(P0.05);断裂模式多为粘结剂断裂的混合破坏,各组断裂模式间无统计学差异(P>0.05);扫描电镜观察A组混合层薄而致密,树脂突长而粗,其余三组混合层不均一,树脂突短而细。结论 3种脱敏剂可显著降低牙本质全酸蚀粘结剂的粘结强度。