Adhesion of different brands of glass ionomer cements to a ceramometal alloy

Aims

The aim of the study was to assess, compare and evaluate the adhesive strength and compressive strength of different brands of glass ionomer cements to a ceramometal alloy.

Materials

(A) Glass ionomer cements: GC Fuji II - GC Corporation, Tokyo; Chem Flex — Dentsply DeTrey, Germany; Glass ionomer FX — Shofu-11, Japan; MR dental — MR Dental Suppliers Pvt. Ltd., England; (B) ceramometal alloy — Ugirex III; (C) cold cure acrylic resin; (E) temperature cum humidity control chamber; and (F) Instron universal testing machine.

Methods

Four different types of glass ionomer cements were used in the study. From each type of the glass ionomer cements, 15 specimens were made to evaluate the compressive strength and adhesive strength, respectively. Fifteen specimens were further divided into 3 subgroups each having 5 specimens. For compressive strength, specimens were tested at 2, 4 and 12 hours by using Instron universal testing machine. To evaluate the adhesive strength, specimens were surface treated with diamond bur, silicone carbide bur and sandblasting, and tested under Instron universal testing machine.

Results and conclusions

It was concluded from the study that the compressive strength as well as the adhesive bond strength of MR dental glass ionomer cement with a ceramometal alloy was found to be maximum compare to other glass ionomer cements. Sandblasting surface treatment of ceramometal alloy was found to be comparatively more effective for adhesive bond strength between alloy and glass ionomer cement.     

制样方法对玻璃离子水门汀与牙釉质间剪切粘接强度的影响

目的:本文主要研究制样方法对玻璃离子水门汀与牙釉质间的剪切粘接强度的影响。方法:将充填好玻璃离子水门汀的模具在制样环境中自然放置10min、20min、30min后移入37℃±1℃恒温恒湿箱中,1h后取出试样,然后放入37℃±1℃去离子水中,24h后分别测试不同制样方法所制备试样的剪切粘接强度。比较不同制样方法对剪切粘接强度的影响。结果:试验结果表明不同的制样方法对剪切强度有显著影响,在制样环境中放置10min所制备的试样,其剪切粘接强度最大,在制样环境中暴露20min后,其强度则显著下降,暴露时间越长,强度下降的越多。结论:不同制样方法对玻璃离子水门汀与牙釉质间的剪切粘接强度极限具有重要的影响,在比较不同文献中玻璃离子水门汀的剪切粘接强度时应注意其试样的制备方法。     

树脂粘结剂和树脂改良玻璃离子粘结托槽后对釉质颜色的影响

目的:比较在粘结托槽前后,树脂粘结剂和树脂改良玻璃离子粘结剂对牙面颜色的影响。方法:60颗新鲜离体前磨牙随机分为空白对照组、树脂粘结剂组和树脂改良玻璃离子组。在粘结托槽前、去托槽后和茶溶液着色后3个时间点,采用松风电脑比色仪测取牙面的L^*、a^*和b^*值,计算牙面粘结托槽前后和着色处理前后的△E*值以评估牙面颜色的变化。结果:托槽粘结前后的△E^*值,树脂粘结剂组(3.18±0.27)与玻璃离子组(3.17±0.64)显著高于对照组(1.89±0.16)(P<0.05);着色处理前后对比的△E^*值,树脂组和玻璃离子组发生临床可识别的颜色变化,△E^*分别为(4.25±0.51)和(4.60±0.52),显著大于对照组(2.43±0.24)(P<0.05);两种粘结剂之间在托槽粘结前后和着色处理前后均未见显著差异。结论:光固化复合树脂粘结系统与树脂加强型玻璃离子粘结系统均会影响牙面颜色,导致牙面易着色,但二者对牙面颜色影响无显著差异。     

玻璃离子粘固剂在夹层修复中的微漏实验研究

目的：测试GIC与牙本质及光固化复合树脂之间的密合性.方法：将56颗颊面制备好牙本质窝洞的成人磨牙随机分为数目相同的A、B两组,用不同方法处理牙本质窝洞后分别充填GIC;用GIC制成的窝洞56个分为C、D两组,分别经酸蚀和未经酸蚀处理后充填复合树脂,所有标本经2%亚甲兰液染色24h后颊舌向剖开,立体显微镜下观测颜料渗入深度.结果：不同处理方法其微漏深度不同,GIC与牙本质的密合性优于与复合树脂的密合（P＜0.01）.结论：夹层技术能增强边缘密合性,酸蚀及EDTA处理后微漏深度变浅（P＜0.01）.     

树脂修饰化玻璃离子托槽粘结剂粘结强度的体外研究

目的：评估一种树脂修饰化的玻璃离子托槽粘结剂在牙面不同处理方式和环境下的两次粘结后的剪切强度情况。方法：将新近拔除的105颗上颌第一前磨牙随机均分成7组,按照说明书的要求完成托槽的粘结。对照组牙面用37%的磷酸处理后,用光固化复合树脂粘结剂（3M,Transbond XT）粘结。其它6组牙面分别在37%的磷酸、GC处理剂（GC Self-Conditioner）、和不做任何处理的条件下,分别在干燥和湿润的环境下用树脂修饰化的玻璃离子（RMGIC;Fuji ORTHO LC,GC Corporation,Tokyo,Japan）粘结,所有牙齿均选用同种托槽。托槽粘结24 h后,在万能测力机下以1 mm/min的速度卸载,并记录下数值。除去牙面和托槽底面多余粘结剂后,重复上述过程。每次卸载后检查牙釉质损坏情况。结果：对照组两次剪切强度有较小的差异,其它GC玻璃离子粘结剂组两次剪切强度没有统计学意义。GC粘结剂不做任何处理组在干燥和湿润的环境下其剪切强度存在明显的差异。干燥环境下,37%的磷酸和GC处理剂处理后,GC粘结剂组两次卸载后的牙釉质均出现不同程度的釉裂或釉质脱落。结论：这种树脂修饰化的玻璃离子粘结剂可以在多种条件下用于托槽的粘结。     

固化玻璃离子水门汀的DSC/TG研究

目的：研究玻璃组成中磷含量对玻璃离子水门汀固化过程的影响。方法：基于SiO2-1／2Al2O3-1／2CaF2-1／2zP2O5,（z=0,1／12．5,1／6．25,1／3．125）组成,制备了不同磷含量的玻璃粉剂,采用DSC／TG热分析技术研究4种不同磷含量玻璃组成、2种市售玻璃离子水门汀和1种聚羧酸锌水门汀对照样品的热分解特点。结果：固化玻璃离子水门汀的基体分解放热峰的温度和形态随磷含量变化而变化,当磷含量增加时,由一个变为两个,且明显变宽。结论：在玻璃离子水门汀固化过程中有磷进入基体中,当磷含量较高时,可以直观地观察到它们对聚合物基体热行为的影响。     

光固化型玻璃离子粘固剂与粉剂型玻璃离子粘固剂粘结正畸带环的牢固性能比较

目的：总结40名固定矫治患者的60颗磨牙分别采用光固化型玻璃离子粘固剂和粉剂型玻璃离子粘固剂粘结正畸带环的牢固性能比较。方法：将60颗上颌第一磨牙随机分为光固化型组和粉剂型组进行间隔粘结,产生两组样本,每组30颗牙,以时间为标准,对每组带环的脱落进行统计学分析。结果：粘入4周后两组带环的脱落计数均为零;粘入8周后粉剂型组的带环脱落计数大于光固化型组;粘入12周后粉剂型组的带环脱落计数明显大于光固化型组。结论：光固化型玻璃离子粘固剂粘结带环的牢固性优于粉剂型玻璃离子粘固剂,可以作为正畸带环粘结的首选材料。     

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。     

Evaluation of Compressive Strength of Hydraulic Silicate-based Root-end Filling Materials

Introduction

Hydraulic silicate cements such as mineral trioxide aggregate (MTA) have many clinical advantages. Newer hydraulic silicate materials have been developed that improve on the limitations of mineral trioxide aggregate such as the long setting time and difficult handling characteristics. The purpose of this study was to examine the effect of saline and fetal bovine serum (FBS) on the setting and compressive strength of the following hydraulic silicate cements: ProRoot MTA (white WMTA; Dentsply International, Tulsa Dental Specialties, Johnson City, TN), EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), MTA Plus (MTAP; Avalon Biomed Inc, Bradenton, FL), and QuickSet (QS; Avalon Biomed Inc, Bradenton, FL).

Methods

Samples of root-end filling materials were compacted into polyethylene molds. Samples were exposed to FBS or saline for 7 days. A universal testing machine was used to determine the compressive strengths.

Results

QS had significantly lower compressive strength than all other materials (P < .001). White MTA and MTAP mixed with liquid had lower compressive strengths after exposure to FBS compared with saline (P = .003). ERRM, MTAP mixed with gel, and QS were not affected by the exposure to FBS.

Conclusions

New silicate-based root-end filling materials, other than QS, have compressive strength similar to MTA. Within the limits of this study, premixed materials and those mixed with antiwashout gel maintain their compressive strength when exposed to biological fluids.     

Bond Strength of Resin Cements to Co‐Cr and Ni‐Cr Metal Alloys Using Adhesive Primers

Purpose: The aim of this study was to evaluate the effectiveness of adhesive primers (APs) applied to Co‐Cr and Ni‐Cr metal alloys on the bond strength of resin cements to alloys. Materials and Methods: Eight cementing systems were evaluated, consisting of four resin cements (Bistite II DC, LinkMax, Panavia F 2.0, RelyX Unicem) with or without their respective APs (Metaltite, Metal Primer II, Alloy Primer, Ceramic Primer). The two types of dental alloys (Co‐Cr, Ni‐Cr) were cast in plate specimens (10 × 5 × 1 mm³) from resin patterns. After casting, the plates were sandblasted with aluminum oxide (100 μm) and randomly divided into eight groups (n = 6). Each surface to be bonded was treated with one of eight cementing systems. Three resin cement cylinders (0.5 mm high, 0.75 mm diameter) were built on each bonded metal alloy surface, using a Tygon tubing mold. After water storage for 24 hours, specimens were subjected to micro‐shear testing. Data were statistically analyzed by two‐way ANOVA and Tukey's studentized range test. Results: The application of Metal Primer II resulted in a significantly higher bond strength for LinkMax resin cement when applied in both metal alloys. In general, the cementing systems had higher bond strengths in Co‐Cr alloy than in Ni‐Cr. Conclusions: The use of AP between alloy metal surfaces and resin cements did not increase the bond strength for most cementing systems evaluated.     

铸造纯钛与树脂水门汀粘结界面疲劳强度的研究

目的：本实验通过体外循环加载模拟口内受力,研究不同的树脂水门汀与铸造纯钛之间粘结界面疲劳强度,以及冷热循环对疲劳强度的影响,为临床应用提供实验依据。方法：用φ5mm×5mm的圆柱形小钛段与φ4mm×2mm小钛片48对分别用Super-Bond C＆B和Panavia F粘接,粘接前粘接面用Alloy Primer预处理,将以上每组中的一半样品置于37℃水浴箱内24h,另一半样品水储24h后再进行5000次冷热循环（5℃←→55℃,浸渍时间为30s）。将样本固定于振动动态测试系统上进行疲劳测试,试验波形为正弦波,应力比R=0,频率为4Hz,测定参照升降法,将疲劳试验结果与之前静载剪切强度测试结果进行对比分析。结果：疲劳极限远小于静载剪切强度值,冷热循环对疲劳强度没有明显影响。疲劳极限值与剪切强度值呈正相关（P〈0.01）。结论：铸造纯钛表面经Alloy Primer处理后与2种树脂水门汀粘固后能耐受106次循环加载的疲劳极限约为静载剪切强度的15%。     

两种托槽粘接剂的比较实验和研究

目的：测定树脂和化学固化型玻璃离子托槽粘接剂的抗剪切粘接强度。方法：100颗离体双尖牙被随机分成两组，每组又按照测试时间的不同分成3个亚组。组1、组2分别用京津釉质粘合剂(树脂)、Ketac—Bond(化学固化型玻璃离子粘接结剂)粘接托槽，对所有实验样本进行了抗剪切粘接强度的测试。结果：①树脂和化学固化型玻璃离子的抗剪切粘接强度随时间的增加而增强。②树脂粘接剂的断裂主要发生在釉质—树脂界面，而化学固化型玻璃离子粘接剂的断裂则主要发生在自身内部。结论：树脂型托槽粘接剂固化后24h以内达到临床应用标准，而化学固化型玻璃离子粘接剂在固化后24h以内达不到该标准，不适合于临床应用。     

Evaluation of Fluoride Release in Chitosan-Modified Glass Ionomer Cements

ObjectiveThis study assessed the influence of chitosan nanoparticles on the fluoride-releasing ability of 4 glass ionomer cement (GIC) through an in vitro analysis.MethodsFour types of GIC (type II light cure universal restorative, type II universal restorative, GC Fuji VII, and type IX) were modified with nanochitosan particles; 10% chitosan was added to the glass ionomer liquid. Six specimens for each of the 4 groups were created, using expendable Teflon moulds. Discs of each type of GIC (n = 6) were immersed in deionised water at various time intervals. Electrodes selective for fluoride ions were employed to analyse the amount of released fluoride at 1, 7, 14, 21, and 28 days.ResultsChitosan-modified GICs showed greater fluoride release than conventional GICs at all time points. All samples showed an initial high release of fluoride that tapered off with time. The total amount of fluoride released increased from the 1st day to the 28th day on adding chitosan to all the 4 types of GIC. Amongst those, type IX high-strength posterior extra with chitosan released a considerably higher quantity of fluoride at all time intervals.ConclusionsIn all the experimental groups, adding chitosan to the glass ionomer liquid had an accelerating effect on its fluoride-releasing property.     

INFLUENCE OF HEMA CONTENT ON THE MECHANICAL AND BONDING PROPERTIES OF EXPERIMENTAL HEMA-ADDED GLASS IONOMER CEMENTS

The purpose of this study was to determine the influence of incrementally added uncured HEMA in experimental HEMA-added glass ionomer cement (HAGICs) on the mechanical and shear bond strength (SBS) of these materials. Increasing contents of uncured HEMA (10-50 wt.%) were added to a commercial glass ionomer cement liquid (Fuji II, GC, Japan), and the compressive and diametral tensile strengths of the resulting HAGICs were measured. The SBS to non-precious alloy, precious alloy, enamel and dentin was also determined after these surfaces were subjected to either airborne-particle abrasion (Aa) or SiC abrasive paper grinding (Sp). Both strength properties of the HAGICs first increased and then decreased as the HEMA content increased, with a maximum value obtained when the HEMA content was 20% for the compressive strength and 40% for the tensile strength. The SBS was influenced by the HEMA content, the surface treatment, and the type of bonding surface (p<0.05). These results suggest that addition of an appropriate amount of HEMA to glass ionomer cement would increase diametral tensile strength as well as bond strength to alloys and teeth. These results also confirm that the optimal HEMA content ranged from 20 to 40% within the limitations of this experimental condition.     

Effect of mixing method on the porosity of encapsulated glass ionomer cement

OBJECTIVE: To observe cement specimens mixed by various methods non-destructively using microfocus computerized tomography (micro-CT) and to evaluate the effect of mixing method on porosity. METHOD: Five glass ionomer cements were used: two were hand-mixed and three were encapsulated. The latter were mixed either by shaking or rotating. Fifteen cylindrical specimens were prepared for each material by each mixing method and stored in distilled water at 37 degrees C until testing. The specimens were observed and analyzed using micro-CT. 201 sliced images were obtained horizontally along the length of the specimens. Three-dimensional reconstructions were made and the sizes, numbers and total volume ratio of bubbles in the specimens were calculated. RESULTS: Mixing method had a significant effect on porosity (P<0.05). For the luting/lining cement, mechanical mixing produced a significantly higher porosity (P<0.05). For the restorative cement, there were only small differences in porosity between specimens mixed by the two methods. More large bubbles were detected in specimens mixed mechanically than by hand for the fluid material. This suggested that for low-viscosity materials bubbles may combine until a certain viscosity is reached during setting. SIGNIFICANCE: The strength of glass ionomer cement is affected by incorporated porosity and this depends on the mixing method. For low-viscosity cements, hand-mixing is favored in order to reduce porosity and increase strength, but this is not generally applicable to high-viscosity cements.     

玻璃离子水门汀加入银合金粉后对其抗压强度和表面硬度的影响

目的：观察玻璃离子水门汀（ＧＩＣ）中直接加入不同比例银合金粉后的机械性能。方法：测试实验材料的抗压强度和表面硬度。结果：加入银合金粉后ＧＩＣ抗压强度和表面硬度明显下降，并且加入量越大，下降越明显。结论：ＧＩＣ中直接加入银合金粉不能改善ＧＩＣ的机械性能。     

Shear Bond Strength of Conventional Glass Ionomer Cements Bound to Mineral Trioxide Aggregate

IntroductionThis study measured the shear bond strength of conventional glass ionomer cements (GICs; Ketac Molar Easymix and Fuji IX) bonded to white mineral trioxide aggregate (WMTA) that had been allowed to set for 2 different time intervals.MethodsForty-eight WMTA specimens were prepared; half were stored for 45 minutes, and the remaining 24 specimens were stored for 72 hours at 37 °C and 100% humidity. Then each group was divided into 2 subgroups of 12 specimens, and each GIC was layered on each of the 2 WMTA preparations. The GIC-WMTA shear bond strengths were measured and were compared by using one-way analysis of variance.ResultsThe shear bond strengths with the 45-minute and 72-hour WMTAs were 8.85 and 9.16 MPa, respectively, for Ketac Molar Easymix and 9.34 and 9.96 MPa, respectively, for Fuji IX. The GIC-WMTA bond strength was not different between GIC applications to WMTA that had set for 45 minutes versus 72 hours (P >.05).ConclusionsGICs might be used over MTA after the MTA has set for 45 minutes to allow single-visit procedures.     

无创伤修复技术治疗乳牙龋齿的临床效果评价

本文报告了应用无创伤修复技术治疗乳牙龋齿６个月后的临床观察结果。方法“选取没有牙髓问题的乳齿患儿、随机分为五组,应用两种充填材料和不同充填技术进行治疗。     

Comparison of the Flexural Strength of Five Adhesive Resin Cements

Statement of Problem : The increased use of adhesive resin cements in bonded prosthetic restorations has led to restorations debonding under function. Purpose : This investigation evaluated the differences in the flexural strength of new adhesive resin cements as a function of specimen age and storage condition. Materials and Methods : Four new dual‐cure cements were compared to C/B Metabond. Twenty specimens of each of the five cements were prepared in a rectangular glass mold (25 × 2 × 2 mm). The new cements were light‐activated with a 550 mW/cm² lamp for 80 seconds on both the top and bottom surfaces. The auto‐cured cement was allowed to set according to manufacturer's directions. Half the specimens were tested immediately after curing while the other half were stored in distilled water at 37°C for 30 days. A three‐point bending test was performed using an Instron at a crosshead speed of 1 mm/min. The results were analyzed by analysis of variance and Scheffé tests ( p < 0.05) to examine the effect of specimen age and storage condition. Results : RelyX ARC exhibited a significantly higher flexural strength compared with Calibra and Panavia F when tested immediately. The standard cement, C/B Metabond, deformed and did not fracture at the immediate test time. After storage, the flexural strength had significantly improved from the immediate test time for Calibra, Cement‐It, Panavia F, and C/B Metabond. However, there were no significant differences in the flexural strength among the cements when tested after 30 days in water at 37°C. Conclusion : Immediately after curing, these new adhesive resin cements are not equivalent, as evidenced by the significant variability in the measured flexural strength. The distinctions among the cements diminish after aging in water, which may be due to residual polymerization or a plasticizing effect from water absorption. Clinical Significance : When light‐cured, all the new adhesive resin cements have greater early strengths than the auto‐cured cement; however, the wide variation in immediate bending strength suggests that some cements may be more appropriate for use in high‐stress clinical situations such as resin‐bonded fixed partial dentures.