Nd:YAG激光对自黏结树脂水门汀与牙本质黏结强度的影响

目的:采用剪切强度实验和扫描电镜,评价脉冲Nd:YAG激光对自黏结树脂水门汀与牙本质之间黏结强度的影响。方法:选择新鲜、无龋、无裂纹的人离体前磨牙10颗,分为颊、舌2部分,暴露牙本质黏结面,形成20个测试试件,随机分为激光组和对照组(n=10)。激光组以0.8W、10Hz脉冲Nd:YAG激光作用于涂墨汁的牙本质表面25s,联合自黏结树脂水门汀RelyX Unicem充填;对照组直接使用自黏结树脂水门汀RelyX Unicem充填于牙本质表面,放置在37℃生理盐水中24h后,测试剪切强度,在牙科显微镜下观察断裂模式并分类。采用SPSS 17.0软件包对数据进行统计学处理。最后,扫描电镜下观察试件的树脂水门汀-牙本质的纵剖面。结果:对照组和激光组的剪切强度分别为(9.48±1.80)MPa和(11.15±1.71)MPa,有显著差异(P<0.05)。牙科显微镜下观察,2组试件断裂大部分发生在树脂水门汀-牙本质界面。扫描电镜观察,2组自黏结树脂水门汀RelyX Unicem与牙本质之间结合较紧密,但均未见树脂突。结论:Nd:YAG激光(0.8W、10Hz)处理牙本质,能提高自黏结树脂水门汀RelyX Unicem与牙本质之间的黏结强度。     

自制纳米羟磷灰石复合树脂与牙体之间微渗漏的实验研究

目的 检测自制纳米羟磷灰石（NHA）复合树脂与牙体组织之间的边缘密合性。方法 健康离体前磨牙30颗制备Ⅰ类洞型,随机分成3组,分别用NHA复合树脂（A组）、卡瑞斯玛复合树脂（B组）、玻璃离子水门汀（C组）充填修复,经冷热循环实验后,采用2%亚甲基蓝染料渗入法观察充填材料与牙体洞壁间边缘微渗漏的情况。结果 A、B、C组染料的渗漏深度分别为（1.20±0.81）、（1.94±0.70）、（1.73±0.54） mm,3组之间的差异无统计学意义（P>0.05）;3组间渗漏程度的差异也无统计学意义（P>0.05）。结论 作为一种新型牙体修复材料,NHA复合树脂与牙体组织之间具有良好的黏结性能。     

2种牙本质黏结系统对不同深度牙本质微拉伸黏结强度的比较

目的:比较2种不同类型的牙本质黏结系统对深层牙本质和浅层牙本质的微拉伸黏结强度的影响.方法:20颗因正畸拔除的第一前磨牙,在釉牙本质界附近去除冠向牙体组织,暴露牙本质平面.按产品说明书要求,分别黏结全酸蚀黏结剂Prime ＆ Bond NT (PB)和自酸蚀黏结剂FL-Bond(FB),蓝色光固化复合树脂修复.黏结好的标本储于37±10℃的蒸馏水中24h后,将样本片切为0.9 mm±0.9 mm的柱状形态.测量样奉黏结界面与髓腔顶部之间的剩余牙本质的厚度(remaining dentin thickness,RDT),RDT≥3mm者为浅层牙本质组,RDT≤2mm者为深层牙本质组,进行微拉伸黏结强度测试,加载速度1mm/min.体视显微镜下观察断裂类型.采用SPSS11.5软件包对结果进行统计学分析.结果:各实验组的微拉伸黏结强度分别为浅层/FB组(22.63±5.43)MPa、浅层/PB组(28.13±7.80)MPa、深层/FB组(18.65.63±5.44)MPa、深层/PB组(26.82±4.85)MPa,全酸蚀黏结剂PB的黏结强度显著高于自酸蚀黏结剂FB(P<0.05).牙本质深度不同,对微拉伸黏结强度的影响无显著差异(P>0.05).各组的断裂类型多为黏结界面断裂.结论:在离体牙上进行微拉伸黏结强度测试时,牙本质深度不同.对全酸蚀黏结剂和自酸蚀黏结剂的黏结强度无显著影响.     

上前牙薄弱根管重塑材料与根管内壁黏结界面的显微分析研究

目的:探索Bis-Core复合树脂、水调玻璃离子重塑根管后与根管内壁的黏结界面的显微结构。方法:选择新鲜拔除的人上前牙,根管治疗后去冠,将牙根从中一剖为二,分别用复合树脂、水调玻璃离子对根管壁进行黏结。硬组织切片机制备样本,光学显微镜和原子力显微镜观察根管重塑后材料与牙体界面的微细结构特征。结果:树脂与牙本质的黏结界面上有5μm厚度的玷污层,牙本质小管内的树脂长度约为20μm,而玻璃离子与牙齿界面结合紧密,但无渗透现象。结论:在与根管内壁的黏结方面,Bis-Core树脂优于水调玻璃离子,树脂渗透是其与牙体牢固黏结成整体的重要因素。     

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目的评价Er,Cr:YSGG激光照射对牙本质与玻璃离子水门汀间抗剪切黏结强度的影响。方法于2008年7月至12月,在中国医科大学口腔医院收集15颗因正畸拔除的无龋坏、无隐裂的完整离体前磨牙。将标本牙的颊侧与舌侧牙本质表面分别用Er,Cr:YSGG激光照射处理(实验组)和涡轮手机处理(对照组),经FX-Ⅱ玻璃离子水门汀充填及冷热循环后进行剪切力实验,计算标本牙的抗剪切黏结强度,体视显微镜下观察牙体组织的剪切断面。结果剪切力实验结果显示:实验组牙本质与充填材料间的抗剪切黏结强度显著高于对照组(P<0.05)。体视显微镜观察:实验组牙体组织的剪切断面凹凸不平,充填物残留更多;对照组则较光滑、平坦。结论Er,Cr:YSGG激光照射会增强牙本质与玻璃离子水门汀间的抗剪切黏结强度。     

脉冲Nd:YAG激光对非龋性硬化牙本质自酸蚀黏结强度的影响

目的:采用微拉伸黏结强度实验,比较脉冲Nd:YAG激光作用于硬化牙本质对复合树脂-硬化牙本质之间自酸蚀黏结强度的影响。方法:选择10颗硬化牙本质视觉分级均为3级以上的面磨损后牙,将磨损面硬化牙本质分为面积近似相等的两部分(约12mm2),随机分为实验组和对照组。实验组以1W、10Hz脉冲Nd:YAG激光作用于硬化牙本质表面,联合自酸蚀黏结剂Adper Prompt L-Pop处理和Z350复合树脂充填;对照组直接使用自酸蚀黏结剂Adper Prompt L-Pop处理硬化牙本质表面,并用Z350复合树脂充填。24h后制作微拉伸试件,测试微拉伸黏结强度,在体视显微镜下观察断裂模式并分类。采用SPSS13.0软件包对试件微拉伸黏结强度值做配对t检验。结果:实验组和对照组的微拉伸黏结强度分别为(18.94±6.81)MPa和(15.76±5.61)MPa。实验组复合树脂与硬化牙本质黏结强度高于对照组,差别有统计学意义(P0.05)。体视显微镜下观察,断裂多发生在黏结树脂-牙本质界面。结论:脉冲Nd:YAG激光处理硬化牙本质,能够提高复合树脂与硬化牙本质之间的自酸蚀黏结强度。     

三种分层充填方法对牙本质黏结强度的影响

目的:对比研究3种分层充填方法对牙本质黏结的微拉伸强度的影响。方法:选取因正畸需要拔除的前磨牙15个,随机分为3组。去除面釉质,暴露平的牙本质表面,在其中央制备3.5mm×3.5mm×3mm的盒形洞。使用Single Bond黏结剂,按使用说明进行牙本质黏结,用Z100复合树脂充填窝洞:A组:分3层水平充填;B组:分3层斜向充填(第一层水平充填,第二、三层近远中向斜向充填);C组:分3层斜向充填(第一、二层近远中向斜向充填,;第三层水平充填)。用硬组织切片机将实验牙切成黏结面积约0.9mm×0.9mm的正方形小条作为试件,用以测试牙本质微拉伸黏结强度。在体视显微镜和扫描电镜下观察样本的断裂界面。结果:C组的微拉伸黏结强度测试值(31.99±5.27)高于A组(24.56±4.90)和B组(31.19±3.90),3种分层充填方法对牙本质微拉伸黏结强度的影响有统计学意义(P<0.05)。体视显微镜和扫描电镜下观察测试样本的断裂多数为黏结界面破坏。结论:3种分层充填方法对牙本质黏结的微拉伸强度存在影响,其中C组的分层充填方法略优于另外两组。因此,在修复较深的牙体缺损时,采用合适的分层充填方法有利于获得良好的黏结效果。     

3种树脂水门汀对CAD/CAM全瓷-牙本质剪切强度的比较

目的:评价3种树脂水门汀对CAD/CAM全瓷-牙本质剪切强度的影响。方法:选取新鲜拔除的人磨牙30颗,制备牙本质黏结面,随机分为3组(n=10),分别选用全酸蚀树脂水门汀RelyX ARC、自酸蚀树脂水门汀Clearfil DCBond和自黏结树脂水门汀RelyX Unicem对CAD/CAM硅酸锂玻璃全瓷进行黏结,测试3种树脂水门汀对CAD/CAM全瓷-牙本质的剪切强度,并通过立体显微镜观察牙本质的黏结界面。采用SPSS11.0软件包对数据进行统计学分析。结果:RelyX ARC组的剪切强度为(15.90±6.15)MPa,Clearfil DC Bond组的剪切强度为(14.41±5.07)MPa,而RelyXUnicem组的剪切强度为(23.29±7.39)MPa,与前2组相比有显著性差异(P<0.05)。立体显微镜观察显示,3组黏结断面均位于牙本质与树脂水门汀之间。结论:自酸蚀树脂水门汀及自黏结树脂水门汀与CAD/CAM硅酸锂玻璃陶瓷修复体的黏结强度不低于传统全酸蚀树脂水门汀,且临床操作简便,为临床全瓷黏结提供了更多便利与选择。     

4种牙色充填材料与乳牙粘结强度的比较研究

目的：比较4种牙色充填材料与乳磨牙的剪切粘结强度,为临床应用提供理论依据。方法：选用滞留乳磨牙80颗,随机分成8组,分别用复合树脂、多聚酸改良复合树脂、树脂改良玻璃离子、玻璃离子及相对应的酸蚀粘结剂或齿面处理剂按使用说明制作牙釉质和牙本质粘结试件,测定其剪切强度,并在体视显微镜下观察试件断面界面破坏情况。结果：4种牙色材料的剪切强度牙釉质组均明显高于牙本质组,复合树脂与多聚酸改良复合树脂组牙质剪切粘结强度无统计学差异,其它任意两组之间均有高度统计学差异。结论：复合树脂与多聚酸改良复合树脂牙质粘结强度无明显差别,均高于玻璃离子和树脂改良玻璃离子,以玻璃离子粘结强度最低。     

牙本质黏结界面的微渗漏与纳米渗漏

目的：观察牙本质黏结界面微渗漏与纳米渗漏,探讨两者的关系。方法：在离体人磨牙的颊、舌侧颈部制备盒形单面洞（直径3mm,洞深2mm）,将牙分为2组,每组5个牙。对2组牙的窝洞分别应用黏结剂Single Bond、Clearfil SE Bond,然后充填复合树脂并光照固化。所有牙齿进行冷热循环5000次,之后在牙齿表面涂指甲油。将牙齿浸泡于500g/L氨化硝酸银液（pH8.0）中,24h后再浸泡于显影液中8h。随后将牙纵向剖开,暴露充填物剖面,在体视显微、扫描电镜下观察剖面充填物龈缘渗漏情况。结果：所有牙剖面修复体龈缘均存在程度不同的微渗漏,有微渗漏的黏结界面处并未发现因黏结原因所造成的裂缝或微裂隙,但在混合层内观察到纳米渗漏。结论：牙本质黏结界面的微渗漏染色不一定因界面裂缝所致,界面无裂缝的纳米渗漏同样可造成微渗漏染色。     

树脂加强型玻璃离子粘固剂粘结强度的研究

目的 检测树脂加强型玻璃离子粘固剂的粘结强度,探讨影响粘结性能的相关因素.方法 30颗健康离体前磨牙分成两组,分别用京津釉质粘合剂和树脂加强型玻璃离子粘固剂初次、二次粘接托槽,测剪切强度及粘结剂残余指数.结果 树脂加强型玻璃离子粘固荆的粘结强度与临床普遍使用的京津釉质粘合剂的粘结强度相近,差异无显著性(P>O.05).结论 树脂加强型玻璃离子粘固剂可以替代复合树脂粘结剂.能够满足临床需要.     

In vitro shear bond strength of resin-based luting cements to dentin

The aim of this study was to determine how resin cement, self-adhesive resin cement, and resin-modified glass ionomer cement affected shear bond strength to dentin. Sixty composite resin disks (3 mm in diameter x 3 mm in length) were prepared and divided into four groups (n = 15): Group 1, composite disk bonded to dentin with composite resin and a bonding agent; Group 2, composite disk bonded to dentin with a self-adhesive resin cement; Group 3, composite disk bonded to dentin with a different self-adhesive resin cement; and Group 4, composite disk bonded to dentin with a resin-modified glass ionomer cement. The composite resin was loaded into a syringe (internal diameter 3 mm), photocured in an oven, and cut into 3 mm slices with a low-speed saw. The samples were bonded to dentin per the manufacturer's instructions. All specimens were stored in distilled water (at 37 degrees C) for 24 hours. The shear bond strength test was conducted using a universal testing machine at a crosshead speed of 0.5 mm/min until failure. Conventional resin cement and a bonding agent exhibited significantly higher shear bond strength values than all other materials tested.     

Suitability of a shear punch test for dental restorative materials.

OBJECTIVE: The aim of the study was to evaluate the suitability of a shear punch test for determining the mechanical properties of dental restorative materials. The method was evaluated by measuring and comparing the shear punch strength of seven different restorative materials, that is amalgam, composite resin, compomer, composite containing pre-reacted glass ionomer filler, resin modified glass ionomer, glass ionomer and polycarboxylate cement. METHOD: The effects of specimen restraining conditions, specimen thickness and test speed on the shear punch strength were evaluated using polycarboxylate cement and two different equipment set-ups. Using the preferred testing regime as determined in the preliminary experiments, the shear punch strength of seven different materials were measured and compared. Twenty disc specimens, 0.5mm thick and 10mm diameter, were prepared for each material, restrained within the test equipment and tested at a speed of 1.0mm/min. RESULTS: The shear punch strength increased as the torque used for restraining a specimen was increased. There was no difference in shear punch strength for specimens of different thickness. The greatest shear punch strength was obtained at the test speed of 1.0mm/min. The shear punch strength values decreased in the order composite>composite containing pre-reacted glass ionomer filler>amalgam>compomer>resin-modified glass ionomer>glass ionomer>polycarboxylate. A difference in the shear punch strength for seven different kinds of restorative materials clearly emerged. Specimen fracture occurred by circumferential cracking for the shear-punch test. However, for some glass ionomer and amalgam specimens radial cracking was also observed. SIGNIFICANCE: This study suggests that the simple test described is suitable for standardization purposes.     

A fluoride-containing composite resin--an in vitro study of a new material for orthodontic bonding

The shear/peel bond strength of a new material, a 'hybrid' of a composite resin and a glass ionomer cement, was compared in vitro with the bond strengths of a composite resin and of a glass ionomer cement. The new material had a significantly greater bond strength than the other materials tested and its properties were very similar to the composite resin. Unlike the glass ionomer cement, etching of the enamel before applying the adhesive is required. The clinical indications for using this new cement are discussed.     

The effect of delayed light exposure on bond strength: light-cured resin-reinforced glass ionomer cement vs light-cured resin.

Under clinical situations, the intervals between material mixing and light exposure during bracket bonding using light-cured resin-reinforced glass ionomer cement may vary for each individual bracket. This study evaluates the bond strength of light-cured resin-reinforced glass ionomer cement subjected to various time intervals between material mixing and subsequent light exposure. This investigation was conducted in two parts. The first part consisted of measuring the enamel surface temperature to define the conditions under which the second part of the study was carried out. One hundred fifteen subjects, 63 males and 52 females, participated in this study. The over-all mean temperature as measured with a noncontact infrared thermometer was 31.9 degrees C. The second part of this study assessed tensile and shear bond strengths of light-cured resin-reinforced glass ionomer cement subjected to immediate light exposure (time interval, 5 minutes) and bond strengths subjected to light exposure at 10, 20, and 40 minutes after material mixing. Light-cured resin-reinforced glass ionomer cement was then compared with light-cured composite resin. Mean tensile and shear bond strengths of light-cured resin-reinforced glass ionomer cement exposed after 40 minutes were 4.5 MPa and 20.5 MPa, respectively. This represented a reduction of approximately 20% when compared with the 5-minute group. Scheffé test showed no statistically significant differences between any two time intervals. Mean bond strengths of the light-cured resin decreased with time. Tensile and shear bond strengths of light-cured resin indicated high statistical significance within groups across time. It could therefore be concluded that the bond strength of light-cured resin-reinforced glass ionomer cement was not affected by the timing of visible light exposure; whereas, the bond strength of light-cured resin decreased as time intervals increased. Light-cured resin-reinforced glass ionomer cement may thus serve as an advantageous alternative to composite resin for bracket bonding.     

Effect of using self-etching primer for bonding orthodontic brackets

Questions over the use of self-etching primers with composite resin adhesives in the bonding of orthodontic brackets remain unsolved. In addition, there are no previous reports on the efficacy of self-etching primers with resin-modified glass ionomer cements for bonding orthodontic brackets in orthodontic dentistry. The purpose of this study was to determine the shear bond strengths of orthodontic brackets bonded with one of four protocols: (1) a composite resin adhesive used with 40% phosphoric acid, (2) the same composite resin used with Megabond self-etching primer, (3) a resin-modified glass ionomer cement adhesive used with 10% polyacrylic acid enamel conditioner, and (4) the same resin-modified glass ionomer cement used with Megabond self-etching primer. The appearance of the tooth surfaces after acid etching or priming was observed with a field-emission scanning electron microscope (FE-SEM). When used with resin-modified glass ionomer cement, Megabond self-etching primer gave no significantly different shear bond strength compared with polyacrylic acid etching. But when used with composite resin adhesive, Megabond self-etching primer gave significantly lower shear bond strength than phosphoric acid etching. However, the shear bond strength of orthodontic brackets bonded with composite resin adhesive after Megabond priming was almost the same as that of brackets bonded with resin-modified glass ionomer cement after polyacrylic acid etching. FE-SEM observation revealed that Megabond self-etching primer produced less dissolution of enamel surface than did phosphoric acid and polyacrylic acid etching. Megabond self-etching primer may be a candidate for bonding orthodontic brackets using the resin-modified glass ionomer cement for minimizing the amount of enamel loss.     

An in vitro study of the bond strength of a glass ionomer cement in the direct bonding of orthodontic brackets

The shear/peel bond strength of a 'no-mix' composite orthodontic bonding resin was compared in vitro with that of a glass ionomer cement. The effect of pre-treatment of the enamel, with either phosphoric acid or polyacrylic acid, prior to using the glass ionomer cement was also assessed. The composite resin had a significantly higher bond strength than the glass ionomer cement. Simple prophylaxis and drying of the enamel achieved the best results when using the glass ionomer cement, whilst etching the tooth surface with phosphoric acid produced a significantly poorer bond to the enamel. Investigation of the site of failure showed the composite resin bonded very well to the tooth and less well to the bracket, whilst the glass ionomer adhered significantly better to the bracket base than to the tooth surface.     

Effect of surface condition of dental zirconia ceramic (Denzir) on bonding

Yttria partially stabilized zirconia (YPSZ) ceramics are suitable for dental and medical use because of their high fracture toughness and chemical durability. The purpose of this study was to examine the bonding behavior of a dental YPSZ ceramic, Denzir. After being subjected to various surface treatments, Denzir specimens were bonded to each other using an adhesive resin composite, glass ionomer, or zinc phosphate cement. Bonding strength was then determined by the shearing test. No significant differences (p>0.05) were observed between SiC- and Al2O3-blasted specimens. In all surface treatments, the shear bond strength significantly (p<0.05) increased in the order of adhesive resin composite cement > glass ionomer cement > zinc phosphate cement. Moreover, silanization with methacryloxy propyl trimethoxysilane slightly increased the bonding strength of the adhesive resin composite cement.     

Bond strength for orthodontic brackets contaminated by blood: composite versus resin-modified glass ionomer cements.

PURPOSE: The purpose of this study was to evaluate and compare the shear bond strengths of a self-cured glass ionomer versus composite cement for bonding of stainless steel buttons with various enamel surface and setting conditions. MATERIALS AND METHODS: Stainless steel orthodontic buttons were bonded using composite material under 3 different enamel and setting conditions: 1) conditioned and dry enamel surface, 2) conditioned and precontamination of the enamel surface with blood before bonding, 3) conditioned and immediate blood contamination postbonding and were compared with 3 different enamel conditions and setting for bonding with the glass ionomer cement: 1) nonconditioned and wet enamel surfaces, 2) nonconditioned and blood contamination of enamel before bonding, and 3) nonconditioned and immediate blood contamination postbonding. The brackets were bonded to 109 recently extracted teeth and allowed to set in a moist plastic container for 24 hours. They were subsequently tested in shear mode with a universal testing machine. The maximum bond strength and the site of bond failure were recorded. In addition, the location of the bond failure was studied. RESULTS: Composite was capable of sustaining greater forces than the resin-modified glass ionomer materials. Hence, it took more force to debond a bracket cemented with composite than with resin-modified glass ionomer. The effect of contamination was similar in both of the materials, and the magnitude of the decrease in bond strength was nearly of the same proportion. The postcontamination values were not significantly different from the uncontaminated bond strength for either material. The type of bond failure was significantly different for the different materials, and there were significant differences among the treatment conditions. CONCLUSION: Composite resin had significantly greater shear strength than resin-reinforced glass ionomer cement. Both materials showed a significant decrease in bond strength when precontaminated with blood. The postcontamination values were not significantly different from the uncontaminated bond strength for either material.