不同浓度单宁酸在不同酸蚀模式下对通用型粘接剂粘接强度的影响

目的研究不同浓度单宁酸在全酸蚀与自酸蚀条件对通用型粘接剂在牙本质表面粘接强度的影响。 方法将60颗无龋离体人磨牙置于存储盒中随机盲取分成2组（全酸蚀A组与自酸蚀B组,n = 30）,再将每组随机分为5个亚组（n = 6）。在使用通用型粘接剂Single Bond Universal（SBU）前,在牙本质面分别涂抹浓度为0%（对照组）、25%、50%、75%和100%的单宁酸3 min并冲洗吹干。实验试件在37 ℃水中保存24 h后进行微拉伸强度测试（μTBSt）。使用Two-Way ANOVA与Games-Howell对数据进行统计学分析。用体式显微镜观察断裂面模式并在扫描电镜（SEM）下观察微拉伸试件的牙本质断端。 结果在全酸蚀模式下,75%单宁酸组粘接强度[（34.51 ± 8.43）MPa]与100%单宁酸组粘接强度[（36.16 ± 5.20）MPa]显著高于其他各组（F = 32.301,P<0.001）;在自酸蚀模式下,25%单宁酸[（31.06 ± 3.41）MPa]可显著提升SBU与牙本质粘接强度（F = 23.570,P<0.001）。双因素分析结果证实,单宁酸浓度（F = 23.134,P<0.001）与酸蚀模式（F = 4.465,P = 0.036）对粘接强度具有显著影响且两要素间显著相关（F = 28.231,P<0.001）。断裂模式分析与电镜观察结果表明,在牙本质表面不同酸蚀模式与不同浓度单宁酸所形成的界面形态差异显著。 结论在不同酸蚀模式下,不同浓度的单宁酸均可显著改善SBU与牙本质的粘接强度。     

NBG-GMA与人牙本质表面的结合机理研究

本文报道自制新化合物NBG-GMA与牙体本质表面钙的结合机理。用单变法和pH滴定法得到NBG-GMA与Ca~( )络合比为2:1,lgk稳为8.9。牙体表面与NBG-GMA溶液湿润接触角为13.65°,比空白试验和NPG-CGE、NBG-CGE的湿润接触角小得多。粘结抗张强度比空白试验大8～9倍。说明NBG-GMA与牙体表面有明显的化学作用。     

Dimensional changes and ultimate tensile strengths of wet decalcified dentin applied with one-bottle adhesives

OBJECTIVES: The objectives of this study were to test the null hypothesis that no dimensional changes in wet decalcified dentin matrices will occur during the application of one-bottle adhesives, and to evaluate the ultimate tensile strengths (UTS) of resin-infiltrated dentin matrices using the microtensile test. METHODS: Dentin disks 0.2 mm thick were prepared from mid-coronal dentin of human unerupted third molars. They were completely decalcified in 0.5 M EDTA (pH 7.4) for 5 days at 25 degrees C and then placed in the bottom of an aluminum well to permit use of the LVDT portion of a thermal mechanical analyzer. Changes in matrix height in response to the application of Single Bond, One-Step or Prime & Bond NT were measured along with the UTS of resin-infiltrated specimens that were compared using a one-way ANOVA and Fisher's PLSD test. RESULTS: All one-bottle adhesives produced a gradual, progressive shrinkage of the decalcified matrix of 26-33%. The shrinkage produced by Single Bond was significantly greater (p<0.05) than that produced by the other adhesives. The UTS of One-Step was significantly higher (<0.05) than that of Prime & Bond NT (42.0+/-13.6 vs 29.7+/-1.9 MPa, respectively), with Single Bond producing intermediate UTS (34.3+/-7.4 MPa). SIGNIFICANCE: If the durability of resin-dentin bonds depends upon the size of interfibrillar spaces for both diffusion channels and resin uptake, then adhesive formulations should be designed to minimize matrix shrinkage during resin infiltration.     

人发缝线的基础研究及临床应用

为寻找理想的缝合材料，以健康人发为原料，经特殊加工，精制成一种针线一体的、无菌、无损伤、无瘢痕的新型医用缝合线。经动物实验及临床应用８１７例，无一例感染，均取得了满意的效果。发现人发缝线有如下特点：表面光洁，粗细适中，抗拉力强，富有弹韧性，结构致密，性质极稳定，生物相容性很好，无毒、无刺激，１８０度返折千次不断裂，遇水、血无膨胀性，埋入兔体内１５０天无明显组织反应，缝合皮肤不引起小灶性感染。效果明显优于丝线和尼龙线。因来源广泛，取材方便，便于普及应用。     

金属表面阳极氧化提高粘接剂与金属粘接性能的研究

作者用PE粘接剂与分别经抛光、喷砂、阳极氧化或复合处理的Durabond、GH_(30)和软质Co-Cr三种合金进行粘接的研究,以考察表面处理对粘接性能的影响。结果表明,经表面复合处理后的上述三种合金与PE粘接剂的抗张粘接强度分别为214.65±51.68、372.88±21.88和349.21±48.32kg/cm~2,显示了较好的粘接性能和耐水稳定性。作者并比较了PE、EB和Panavia-EX树脂等的粘接效果展果:除PE和Panavia-EX与Durabond粘接TBS值无显著性差异外(P>0.05),PE与另外两种合金粘接的TBS值均高于Panavia-EX和EB复合树脂(P<0.01)。PE与Durabond粘接的TBS值亦高于EB复合树脂。     

不同处理方法对同种带瓣主动脉组织结构及机械抗张强度的影响

对同种带瓣主动脉的取材，处理，保存进行了研究，建立了梯度降温的计算机程序，通过组织及超微结构观察，组织机械抗张强度测试，证实抗生素灭菌，深低温保存方法可以较好地保持同种移植物的生理特性，保持纤维组织及成纤维细胞的结构完整，保持组织机械抗张强度。     

纤维蛋白胶粘合修复周围神经抗牵拉强度动态变化的实验研究

目的　了解用纤维蛋白胶粘合修复周围神经后早期的抗牵拉强度及其动态变化。方法　Wistar大鼠 96只 ,按手术先后随机分为神经缝合组 (n =48)和粘合组 (n =48)。切断大鼠左侧坐骨神经 ,缝合组用 11 0无创尼龙缝线作端端缝合 ,粘合组用纤维蛋白胶粘合两断端。于术后 0、3、7、14、2 1和2 8d 6个时间组 (每组n =8)取材 ,测量神经断裂时的最大负荷、功耗 ,并描绘出神经应力 -应变曲线。结果　神经抗牵拉强度曲线表现出粘弹性特性。缝合组与粘合组的最大抗牵拉强度及功耗 ,在术后 0、14、2 1和 2 8d时差异无显著意义 (P >0 .0 5 ) ;但在术后 3、7d时差异有显著意义 (P <0 .0 1,P <0 .0 5 )。结论　纤维蛋白胶有足够的抗牵拉强度 ,可以满足大鼠神经修复的需要。     

脉冲Nd:YAG激光照射对牙釉质粘结性能的影响

目的 :探讨脉冲Nd :YAG激光作为牙体表面处理技术对牙釉质粘结性能的影响。方法 :分别用 1W、2 0Hz,1W、15Hz,1.5W、2 0Hz,1.5W、15Hz,2W、15Hz共 5个能量输出组照射离体牙釉质表面 ,测定其与复合树脂的抗张粘结强度 ,并与未处理组、35 %磷酸酸蚀组进行对照。结果 :激光照射组中输出能量为 1W、15Hz时抗张粘结强度最高 (3.87± 1.91MPa) ,其次是 1W、2 0Hz(3.4 3± 1.4 8MPa) ,两组间无显著差异 (P >0 .0 5 ) ,但都显著高于其它三个激光照射组及未处理组 (P <0 .0 5 )。酸蚀组的抗张粘结强度最高 (8.5 0± 3.0 2MPa) ,显著高于其它 6个实验组(P <0 .0 5 )。结论 :脉冲Nd :YAG激光处理牙釉质表面可改善粘结性能 ,抗张粘结强度受激光输出能量的影响 ,当激光输出能量为 1W、15Hz时抗张粘结强度最高 ,但低于酸蚀组。脉冲Nd :YAG激光能否作为一种牙釉质表面处理技术应用于临床尚需进一步研究     

Optimized thrombin dilution protocol for a slowly setting fibrin sealant in surgery

Summary BACKGROUND: Fibrin sealants find applications in many surgical fields (e.g., plastic and reconstructive surgery) where a slower setting time of about 30 to 60 s is beneficial. This can be achieved by diluting the thrombin component of the fibrin sealant to a concentration of about 5 IU/ml. This work was carried out to define an optimal dilution medium for thrombin which maintains all relevant functional parameters of the fibrin sealant and which is easy to prepare with components available in most operating theaters. METHODS: Different performance criteria of a fibrin sealant were tested in vitro by the following methods: adhesive strength in a rat skin adhesion model, turbidimetry and scanning electron microscopy to determine the fibrin clots structure, tensile strength of the fibrin clots by measuring the force at break. The cross-linking of the fibrin sealant by factor XIII (FXIII) as a function of the calcium concentration was assessed by quantitative electrophoresis. RESULTS: A dilution medium containing only calcium chloride in a concentration of about 20 mM performed best in most of the applied test systems. Dilution media with high ionic strength resulted in clots with low adhesive and tensile strength, thin fibrin fibers, and low clot elasticity. Dilution media without calcium prevented proper cross-linking of the resulting fibrin clots and led to clots with low tensile and adhesive strength. CONCLUSIONS: We present an optimized simple dilution protocol for the dilution of the thrombin component for a slowly setting fibrin sealant.