不同粘结材料对VITA Mark Ⅱ粘结强度的研究

目的：比较4种常用粘结材料对VITA MarkⅡ可切削陶瓷的粘结强度。方法：应用4种常用粘结材料（Fuji PLUS、Panavia F、RelyX Unicem和FL—BOND＋Beautifil Flow），将切割好的瓷片、牙片粘结，水浴50h后和冷热循环3000次后测其剪切强度，体视显微镜观察粘结破坏情况。结果：水浴50h组中Panavia F、RelyX Unicem和FLBOND＋Beautifil Flow的剪切强度显著高于Fuji PLUS的剪切强度（p〈0．05）。冷热循环3000次组中Panavia F的剪切强度最高，与另3组的差异有统计学意义（p〈0．05）。结论：Panavia F可用于MarkⅡ瓷的粘结，树脂改良型玻璃离子和自酸蚀粘结剂配合流动树脂的初期粘结强度尚可，但冷热循环后粘绪强度下降明显。     

不同粘接剂对二氧化锆桩固位力的影响

目的探讨不同粘接剂对二氧化锆桩与根管内牙本质粘接强度的影响。方法将60颗完整无龋坏的离体上颌中切牙自釉牙骨质界处截断牙冠,根管桩道预备,制作二氧化锆桩核。60颗牙随机分为6组,分别用磷酸锌水门汀、聚羧酸锌水门汀、玻璃离子水门汀i、Bond加LuxaCore双固化树脂、RelyX Unicem树脂、32%磷酸加ESPE RelyX Unicem树脂粘固二氧化锆桩核。万能力学试验机进行推出测试,记录粘接强度,并对数据行统计学分析。结果 32%磷酸加ESPE RelyX Unicem树脂组、ESPE RelyX Unicem树脂组i、Bond加Luxa Core树脂组、聚羧酸锌水门汀组、玻璃离子水门汀组、磷酸锌水门汀组的二氧化锆桩粘接强度分别为（15.06±1.80）MPa、（11.57±1.33）MPa（、10.42±1.24）MPa（、7.30±1.05）MPa（、6.99±0.87）MPa（、3.97±0.95）MPa,固位力依次降低。其中32%磷酸加ESPE RelyX Unicem树脂组的固位力显著高于其他组,两两比较差异均有统计学意义（P〈0.05）;ESPE RelyX Unicem树脂组与Luxa Core树脂组之间（P=0.590）,聚羧酸锌组和玻璃离子组之间（P=0.490）的差异均无统计学意义;磷酸锌水门汀的粘接强度最低,与其它组比较差异均有统计学意义（P〈0.05）。结论临床粘固二氧化锆桩,树脂类粘接剂固位力较强,自粘接系统加用酸蚀技术可以显著提高二氧化锆桩在根管内的粘接强度。     

树脂粘结剂与瓷表面处理对全瓷粘结微拉伸强度的影响

目的 研究3种树脂粘结剂配合2种瓷表面处理方法对全瓷粘结微拉伸强度的影响.方法 制作60个体积为5mm×6mm×8mm瓷试件(Empress Ⅱ),抛光后分成两组:对照组和HF SIL组(5%氢氟酸酸蚀20秒,硅烷处理1分钟).分别采用3种树脂粘结剂(RelyX Unicem, Variolink或Panavia F)与复合树脂粘结,37℃保存7天,切割成接触面积为1.0mm2的75个柱形体.试件经热循环(5℃～55℃循环3000次)后,测量粘结微拉伸强度(uTBS).结果 表面处理因素有重要意义(HF SIL组>对照组).对照组中Rely X Unicem的uTBS明显高于Variolink和Panavia F.HF SIL组中经RelyX Unicem和Variolink的uTBS明显高于Panavia F.结论 无论使用何种树脂粘结剂,在粘结前进行酸蚀和硅烷处理都是必要的.     

自粘接树脂水门汀与两种粗化处理的二硅酸锂陶瓷的粘接性能评价

摘要］目的：评价自粘接树脂水门汀与喷砂和氢氟酸酸蚀两种方式粗化处理的二硅酸锂陶瓷的粘接强度及耐久性。材料和方法：制作二硅酸锂瓷片183个,烧结后随机分为2组分别进行氢氟酸酸蚀和喷砂,随后根据粘接策略的不同分为RU（RelyX Unicem）、RU200(RelyXTM U200)以及RV(silane+RelyX Veneer) 3个亚组分别制作粘接试件。各组试件一半于37℃下水储24h,另一半进行20000次冷热循环,随后测试剪切粘接强度。氢氟酸酸蚀、喷砂及未进行粗化处理的陶瓷试件采用扫描电镜观察表面形貌。结果：氢氟酸组产生显著高于喷砂组的粘接强度（p<0.05）;单纯应用自粘接树脂水门汀组的粘接效果与传统树脂水门汀结合硅烷预处理组无统计学差别（p=0.057）;所有组的粘接强度在老化后均显著降低（p<0.05）。结论：氢氟酸酸蚀可以获得较氧化铝喷砂处理更佳的粘接效果;自粘接树脂水门汀在无需硅烷预处理的条件下用于二硅酸锂陶瓷的粘接可获得较好的粘接效果。     

3种树脂水门汀对可切削玻璃陶瓷粘接后断裂强度的影响

目的：研究3种树脂水门汀对可切削玻璃陶瓷粘接后断裂强度的影响。方法收集人离体磨牙60颗,垂直牙长轴磨除面釉质;将IPS e.max CAD瓷块加工成片状试件,用体积分数9.5%氢氟酸凝胶处理后,随机分成3组,每组20个,分别使用Multilink? N多功能粘接系统+Monobonds?S（A组）、RelyX?Ultimate树脂水门汀+Scotchbond?通用粘接剂（B组）、RelyX?Unicem 2树脂水门汀（C组）进行粘接;每组瓷片粘接后再分成1、2两个亚组,每组10个,A1、B1、C1组不进行冷热循环,A2、B2、C2组进行冷热循环。在万能试验机上测试所有瓷片的断裂载荷。结果 A1、A2、B1、B2、C1、C2组的试件断裂载荷值分别为：（1763±128）N、（1563±115）N、（1861±135）N、（1676±137）N、（1446±153）N、（1038±95）N。各组试件断裂载荷差异存在统计学意义（F=52.279,P＜0.001）,不同种树脂水门汀（F=94.104,P＜0.001）、冷热循环（F=63.818,P＜0.001）分别对瓷片断裂载荷有显著影响。LSD检验结果显示,A、B、C 3组试件断裂载荷值差异具有统计学意义（P＜0.05）,其中B组的断裂载荷最高,C组最低。结论不同种树脂水门汀对瓷片粘接后断裂强度的影响不同,同时处理瓷片和牙面的树脂水门汀可提高瓷片粘接后的断裂强度。冷热循环降低粘接后瓷片的断裂强度。     

不同酸蚀处理对IPS e．max Press铸瓷与树脂水门汀粘结强度影响的研究

目的研究5％和10％氢氟酸处理IPS e．max Press铸瓷以及处理时间,对瓷与树脂水门汀粘结强度的影响。方法制取标准瓷试件126个,根据酸蚀时间的不同分为7组,每组包括5％和10％浓度两个亚组（n=9）,在表面处理后测定瓷与树脂水门汀的粘结强度;每组取2个试件进行扫描电镜观察。结果5％氢氟酸酸蚀60s和10％氢氟酸酸蚀20s可获得最大粘结强度,分别为33．98&#177;4．78MPa和32．90&#177;4．74MPa,两者间无显著性差异（P〉0．05）。扫描电镜可见酸蚀时间与瓷表面微观形貌有直接关系。结论氢氟酸浓度及处理时间对e．max Press铸瓷与树脂粘结强度有显著影响,合理的控制酸蚀条件是非常必要的。     

四种树脂水门汀黏结牙本质剪切强度的比较

目的:评价4种树脂水门汀与牙本质黏结剪切强度。方法:新鲜拔除的无龋损人第三磨牙48个,随机分为4组(n=12),制备颊侧牙本质黏结面,分别与4种树脂水门汀(Unicem、Panavia F、VariolinkⅡ、Vitique)黏结处理,测试剪切强度,SEM观察牙本质黏结界面。结果:4种树脂水门汀中RelyX Unicem(12.84±2.29)MPa与Panavia F(14.93±3.73)MPa、Vitique(11.03±2.57)MPa之间无显著性差异(P>0.05),而他们均显著高于VariolinkⅡ(5.43±1.25)MPa(P<0.05)。结论:新型自黏结树脂水门汀RelyX Unicem可以取得与牙本质良好的黏结效果,且美观,易于使用,节省操作时间,为黏结修复体提供了一种新的选择。     

三种树脂水门汀抗压强度及成膜厚度的实验研究

目的：对比研究三种临床常用的树脂水门汀的抗压强度及成膜厚度特性。方法：选用Vitique、Variolink II及RelyX Unicem三种树脂水门汀,每种材料各选用20个试样,均分为两组。一组将三种树脂水门汀采用传统调拌硬纸板进行调拌,待其凝固后进行抗压强度的测试;另一组将树脂水门汀试样按照ISO 6876提供的方法进行成膜厚度的测试。用SPSS软件对两种性能的测试数据进行统计分析。结果：三种材料的抗压强度：Vitique为250.5±24.5MPa,Variolink II为315.3±32.1MPa,RelyX Unicem为385.8±37.2MPa。任意两组间的抗压强度均存在显著差异（P〈0.05）,抗压强度按由高至低为RelyX Unicem〉Variolink II〉Vitique。三种材料的成膜厚度：Vitique为22.6±2.5μm,Variolink II为29.6±3.2μm,RelyX Unicem为9.6±0.9μm。任意两组间的成膜厚度均存在显著差异（P〈0.05）,成膜厚度按由大到小为Variolink II〉Vitique〉RelyX Unicem。结论：RelyX Unicem具有较高的抗压强度及较薄的成膜厚度,适用于各种临床修复体的粘接。Vitique较Variolink II更适合用作美学区修复的粘接材料。     

硅烷偶联剂及自酸蚀粘结剂对VitaMarkⅡ与牙本质粘结强度的影响

目的：比较硅烷偶联剂对VITAMarkⅡ可切削陶瓷的粘结强度的影响。方法：将切割好的72个瓷片经打磨酸蚀后随机分为2组：实验组应用硅烷偶联剂,对照组无处理。每组再分4个亚组,与4种粘结材料（RelyXVeneer、PanaviaF、RelyXUnicem和FL-BOND＋Beautifil Flow）粘结,万能材料试验机测其剪切强度,扫描电镜观察粘结界面。结果：对照组中RelyX Veneer、PanaviaF和RelyX Unieem的剪切强度显著高于FL-BOND＋BeautifilFlow的剪切强度（P〈0．05）。实验组中4种粘结材料间的差异无统计学意义（P〉0．05）。硅烷偶联剂的应用提高了4种粘结材料的剪切强度。结论：硅烷偶联剂可提高MarkⅡ瓷的粘结强度。     

不同酸蚀处理对IPS e.max(R) Press铸瓷与树脂水门汀粘结强度影响的研究

目的 研究5%和10%氢氟酸处理IPS e.max(R) Press铸瓷以及处理时间,对瓷与树脂水门汀粘结强度的影响.方法 制取标准瓷试件126个,根据酸蚀时间的不同分为7组,每组包括5%和10%浓度两个亚组(n=9),在表面处理后测定瓷与树脂水门汀的粘结强度;每组取2个试件进行扫描电镜观察.结果 5%氢氟酸酸蚀60s和10%氢氟酸酸蚀20s可获得最大粘结强度,分别为33.98±4.78MPa和32.90±4.74MPa,两者间无显著性差异(P>0.05).扫描电镜可见酸蚀时间与瓷表面微观形貌有直接关系.结论 氢氟酸浓度及处理时间对e.max(R) Press铸瓷与树脂粘结强度有显著影响,合理的控制酸蚀条件是非常必要的.     

不同树脂粘固剂对瓷与牙本质粘接强度的比较研究

目的 评价不同种类树脂粘固剂与瓷-牙本质粘接强度的差异,以期为临床提供参考.方法选取无龋坏青年人前磨牙制备牙本质粘接面,铸造直径为3 mm、高为3 mm的圆柱状瓷块(IPS e.max Press)80个,分为A、B、C、D、E 5组.分别选用树脂粘固剂A(Variolink Ⅱ)、B(MultilinkAutomix)、C(Multilink Sprint)、D(Rely X Unicem)和E(BisCem)将瓷块粘固于牙本质粘接面上,每组制成16个试样.37℃水储24 h后每组8个试样直接测试剪切粘接强度,另8个试样进行5000次冷热循环后测试粘接强度,扫描电镜观察粘接面形态.对同种粘固剂冷热循环前后的粘接强度进行双样本t检验.结果冷热循环前A组粘接强度[(22.3±3.9)MPa]最大,B组[(18.1±3.5)MPa]次之,再次为D组[(14.1±2.3)MPa]和E组[(11.7±4.2)MPa],C组[(11.3±3.6)MPa]最小.冷热循环后A组粘接强度[(17.8±2.3)MPa]仍最大,B组[(14.4±3.5)MPa]和D组[(13.2±2.5)MPa]次之,再次为E组[(8.9±3.2)MPa],C组[(7.0±2.4)MPa]最小.与冷热循环前相比,冷热循环后A、B、C 3组粘接强度均下降,差异有统计学意义(P<0.05);D组和E组粘接强度下降不明显(P>0.05).结论以全酸蚀粘接技术为基础的树脂粘固剂的粘接强度大于以自酸蚀粘接技术为基础的树脂粘固剂和自粘接型树脂粘固剂.     

3种树脂粘接水门汀与铸造纯钛粘接强度研究

目的：研究3种复合树脂粘固剂与铸造纯钛的粘接强度。方法：用牙科铸钛的方法制作直径分别为4mm和5mm的钛棒,切割成长度为4mm的小钛片。2种规格的钛片配对粘接面用400～1200目碳化硅砂纸在流水下打磨抛光,使之呈均匀一致的平面。50μm氧化铝喷砂,另一组表面不喷砂作为对照,分别使用Super-BondC＆B、Panavia F、Rely X Unicem 3种复合树脂粘固剂粘接。扫描电镜观察喷砂前后铸造纯钛的表面形态。复合树脂粘接剂固化后经37℃恒温水浴24h以及5000次5～55℃冷热循环,测试剪切强度。用SAS的ANOVA过程对各组数据进行分析。结果：喷砂前后纯钛与Panavia F的剪切强度最高,分别为（26.62±3.40）MPa、（23.71±5.28）MPa;5000次冷热循环后,喷砂组的铸造纯钛与Panavia F的剪切强度最高（27.12±8.68）MPa;未喷砂的铸造纯钛与Super-Bond C＆B、Rely X Unicem的粘接强度最低,并且有12.5%的脱落率。结论：本实验结果表明喷砂可以提高Super-Bond C＆B、Panavia F、Rely X Unicem的粘结力和粘结耐久力。不喷砂时,Panavia F与铸造纯钛之间能获得较高的粘接强度和良好的粘接耐久性,喷砂以后优势不再明显。     

Influence of ceramic surface conditioning and resin cements on microtensile bond strength to a glass ceramic

STATEMENT OF PROBLEM: It is not clear how different glass ceramic surface pretreatments influence the bonding capacity of various luting agents to these surfaces. PURPOSE: The purpose of this study was to evaluate the microtensile bond strength (microTBS) of 3 resin cements to a lithia disilicate-based ceramic submitted to 2 surface conditioning treatments. MATERIAL AND METHODS: Eighteen 5 x 6 x 8-mm ceramic (IPS Empress 2) blocks were fabricated according to manufacturer's instructions and duplicated in composite resin (Tetric Ceram). Ceramic blocks were polished and divided into 2 groups (n=9/treatment): no conditioning (no-conditioning/control), or 5% hydrofluoric acid etching for 20 seconds and silanization for 1 minute (HF + SIL). Ceramic blocks were cemented to the composite resin blocks with 1 self-adhesive universal resin cement (RelyX Unicem) or 1 of 2 resin-based luting agents (Multilink or Panavia F), according to the manufacturer's instructions. The composite resin-ceramic blocks were stored in humidity at 37 degrees C for 7 days and serially sectioned to produce 25 beam specimens per group with a 1.0-mm(2) cross-sectional area. Specimens were thermal cycled (5000 cycles, 5 degrees C-55 degrees C) and tested in tension at 1 mm/min. Microtensile bond strength data (MPa) were analyzed by 2-way analysis of variance and Tukey multiple comparisons tests (alpha=.05). Fractured specimens were examined with a stereomicroscope (x40) and classified as adhesive, mixed, or cohesive. RESULTS: The surface conditioning factor was significant (HF+SIL > no-conditioning) (P<.0001). Considering the unconditioned groups, the microTBS of RelyX Unicem was significantly higher (9.6 +/- 1.9) than that of Multilink (6.2 +/- 1.2) and Panavia F (7.4 +/- 1.9). Previous etching and silanization yielded statistically higher microTBS values for RelyX Unicem (18.8 +/- 3.5) and Multilink (17.4 +/- 3.0) when compared to Panavia F (15.7 +/- 3.8). Spontaneous debonding after thermal cycling was detected when luting agents were applied to untreated ceramic surfaces. CONCLUSION: Etching and silanization treatments appear to be crucial for resin bonding to a lithia disilicate-based ceramic, regardless of the resin cement used.     

Interfacial fracture toughness of different resin cements bonded to a lithium disilicate glass ceramic

Objectives

To evaluate the effect of HF acid etching and silane treatment on the interfacial fracture toughness of a self-adhesive and two conventional resin-based cements bonded to a lithium disilicate glass ceramic.

Methods

Lithium disilicate glass ceramic discs were prepared with two different surface preparations consisting of gritblasted with aluminium oxide, and gritblasted and etched with hydrofluoric acid. Ceramic surfaces with a chevron shaped circular hole were treated by an optimized silane treatment followed by an unfilled resin and then three different resin cements (Variolink II, Panavia F2, and Multilink Sprint). Specimens were kept in distilled water at 37 °C for 24 h and then subjected to thermocycling. The interfacial fracture toughness was measured and mode of failures was also examined. Data were analysed using analysis of variance followed by T-test analysis.

Results

No statistically significant difference in the mean fracture toughness values between the gritblasted and gritblasted and etched surfaces for Variolink II resin cement was found (P > 0.05). For the gritblasted ceramic surfaces, no significant difference in the mean fracture toughness values between Panavia F2 and Variolink II was observed (P > 0.05). For the gritblasted and etched ceramic surfaces, a significantly higher fracture toughness for Panavia F2 than the other cements was found (P < 0.05).

Conclusions

The interfacial fracture toughness for the lithium disilicate glass ceramic system was affected by the surface treatment and the type of luting agent. Dual-cured resin cements demonstrated a better bonding efficacy to the lithium disilicate glass ceramic compared to the self-adhesive resin cement.

Clinical significance

The lithium disilicate glass ceramic surfaces should be gritblasted and etched to get the best bond when used with Panavia F2 and Multilink Sprint resin cements, whereas for the Variolink II only gritblasting is required. The best bond overall is achieved with Panavia F2.     

偶联剂和不同粘接剂对纤维桩粘接强度的影响

目的:利用薄片推出实验比较硅烷偶联剂和三种树脂粘接剂对纤维桩剪切粘接强度的影响.方法:60颗因牙周病等原因拔除的上颌单根前牙,根管治疗后行纤维桩修复的桩道预备.随机分为5组,每组12颗牙.分别采用下列粘接剂粘接Matchpost纤维桩:A组:Paracore粘接剂+偶联剂;B组:Paracore粘接剂;C组:Panavia F粘接剂+偶联剂;D组:Panavia F粘接剂;E组:Multilink N粘接剂+偶联剂.纤维桩粘接后,在牙根中部横向切割1.0mm层厚切片2个,在Zwick Z100材料试验机上行薄片推出试验(Push-Out Bond Test),记录失败载荷,计算剪切粘接强度,体视显微镜观察粘接失败类型.结果采用SPSS 11.5进行方差分析和χ2检验.结果:五组样本的剪切粘接强度(MPa)分别为A组:14.69±2.76;B组:9.46±3.11;C组:13.12±3.10;D组:10.40±3.30;E组:13.86±3.81,方差分析提示五组间差异有统计学意义(P <0.01).采用偶联剂处理时,Paracore粘接剂和Panavia F粘接剂与纤维桩间的剪切粘接强度均高于未用偶联剂处理者(P <0.05).采用偶联剂处理时,三种树脂粘接剂与纤维桩的剪切粘接强度间差异无统计学意义(P >0.05).五组粘接失败类型间差异有统计学意义(P <0.05),未采用硅烷偶联剂处理纤维桩表面者,出现纤维桩-粘接剂界面失败者增多.结论:在树脂粘接前,玻璃纤维桩表面氢氟酸酸蚀后,采用硅烷偶联剂处理可显著提高纤维桩与树脂粘接剂间的剪切粘接强度.     

Effect of surface treatment on the initial bond strength of different luting cements to zirconium oxide ceramic

The objective of this study was to compare the shear bond strength to zirconium oxide ceramic of adhesive-phosphate-monomer-containing (APM) and non-APM-containing (nAPM) luting cements after different surface treatments. nAPM cements: Bifix QM, Dual Cement, Duo Cement Plus, Multilink Automix, ParaCem Universal DC, PermaCem Smartmix, RelyX ARC, Variolink Ultra, and Variolink II; APM cements: Panavia EX, Panavia F2.0, and RelyX UniCem. Groups of ten test specimens were each prepared by layering luting cement, using cylindrical Teflon molds, onto differently treated zirconium dioxide discs. The surface treatments were airborne-particle abrasion with 110 μm alumina particles, silica coating (SC) using 30 μm alumina particles modified by silica (Rocatec System) or SC and silanization. Bifix QM and Multilink Automix were used in combination with an additional bonding/priming agent recommended by the manufacturers. After 48 h of water storage, each specimen was subjected to a shear test. Combinations involving APM-containing cements (14.41–23.88 MPa) generally exhibited higher shear bond strength than those without APM (4.29–17.34 MPa). Exceptions were Bifix QM (14.20–25.11 MPa) and Multilink Automix (19.14–23.09 MPa) in combination with system-specific silane or priming agent, which were on the upper end of shear bond strength values. With the use of the Rocatec system, a partially significant increase in shear bond strength could be achieved in nAPM cement. Modified surface treatment modalities increased the bond strength to zirconium oxide, although the most important factor in achieving a strong bond was the selection of a suitable cement. System-specific priming or bonding agents lead to further improvement.     

氢氟酸处理时间对玻璃陶瓷与树脂粘接耐久性的影响

目的 评价不同氢氟酸处理时间对玻璃陶瓷表面与树脂粘接耐久性的影响,以期为玻璃陶瓷表面氢氟酸处理时间的正确选择提供临床参考.方法 可切削玻璃陶瓷(PmCAD)表面接受4.8%氢氟酸处理0 s(对照组)、30 s(30 s氢氟酸处理组)和60 s(60 s氢氟酸处理组),每组32个陶瓷片.使用三维激光共聚焦显微镜测量陶瓷片表面粗糙度参数(Ra)和表面积.陶瓷片与4种粘接套装(硅烷偶联剂和树脂粘接剂:A:Monobond S和Variolink Ⅱ;B:Clearfil Ceramic Primer和Clearfil Esthetic Cement;C:GC Ceramic Primer和Linkmax HV;D:Porcelain Liner M和SuperBond)粘接形成粘接试件,每组16个陶瓷片直接测量粘接强度,16个陶瓷片经30 000次冷热循环后测量粘接强度.结果 对照组、30和60 s氢氟酸处理组Ra值[分别为(3.89±1.94)、(12.53±0.80)、(13.58±1.10)μm]及表面积[分别为(7.81±2.96)、(30.18±2.05)、(34.16±1.97)mm2]随着氢氟酸处理时间的延长而显著增加(P<0.05).同种粘接套装相同氢氟酸处理时间下冷热循环后试件的粘接强度均显著低于冷热循环前(P<0.05).冷热循环后粘接套装A、B的粘接强度随着氢氟酸处理时间的延长而显著增加[A:分别为(3.59±3.51)、(16.18±2.62)、(20.33±2.45)Mpa;B:分别为(4.74±2.08)、(7.77±1.55)、(13.45±3.75)Mpa];粘接套装D 30 s氢氟酸处理组的粘接强度[(22.00±1.64)Mpa]显著高于相应对照组[(12.96±4.17)Mpa],但与60 s氢氟酸处理组[(20.42±3.01)Mpa]相比,差异无统计学意义(P>0.05);氢氟酸处理时间未对粘接套装C的粘接强度产生显著影响.结论 氢氟酸处理能提高玻璃陶瓷与树脂的粘接耐久性,氢氟酸处理时间的选择不仅取决于陶瓷表面结构的变化,也取决于所使用的粘接套装.     

Bond strength of selected composite resin-cements to zirconium-oxide ceramic

Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test for more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (α=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-W<0.001). The worst techniques were Lava TM + sandblasting + Silane + Rely X; Lava TM + sandblasting + Silane + Multilink and Lava TM + CoJet + silane + Multilink. Adhesive failure (separation of cement and ceramic) was produced at a lesser force than cohesive failure (fracture of cement) (p-value M-W<0.001). Electron microscopy confirmed that the surface treatments modified the zirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Key words:Shear bond strength, silica coating, surface treatment, zirconia ceramics, phosphate monomer.     

Effect of simulated pulpal pressure on self-adhesive cements bonding to dentin

OBJECTIVES: To evaluate the bonding effectiveness of self-adhesive luting cements to dentin in the presence of simulated hydrostatic intrapulpal pressure (PP). METHODS: Thirty composite overlays (Aelite All Purpose Body) were luted to deep-coronal dentin surfaces using four self-adhesive resin cements (Rely X Unicem, G-Cem, Multilink Sprint, Bis-Cem) and one total-etch system (Calibra). Half of the specimens resin cements were applied under a PP of 15 cm H2O. After storage in a moist condition for 1 month (37 degrees C, 100% relative humidity), specimens were sectioned into microtensile beams (1mm2) and stressed to failure with the microtensile bond strength test (microTBS). Data were statistically analyzed with Kruskal-Wallis ranking (p<0.05) and Mann-Whitney tests (p<0.001). The fracture pattern was evaluated under SEM. RESULTS: Bond strength of Calibra fell significantly when PP was applied during bonding (p<0.05). Rely X Unicem and Bis-Cem performed better under PP. No significant differences for Multilink Sprint and G-Cem bonded specimens were recorded with or without PP. SIGNIFICANCE: Simulated PP influences the adhesive performance of resinous cements. The predominance of acid-base reactions or radical polymerization may explain the different behavior of self-adhesive cements when changing substrate wetness. The application of constant intrapulpal perfusion should be considered when simulating luting procedures in vitro.