粘接银汞修复后牙体的抗折力研究

目的:评价不同的银汞粘接剂应用于粘接银汞修复时,修复后牙体的抗折力差异.方法:选50个健康的上颌前磨牙,除10个作空白对照外,其余40颗在(牙合)面制备近远中邻(牙合)洞,分为4组(直接银汞充填组;树脂加强型玻璃离子水门汀组;玻璃离子水门汀组;树脂型银汞粘接剂组).样品37℃水浴72 h,5℃到55℃水浴循环2 500次,然后用振动动态测试系统进行抗折实验,直至破裂,记录时间.结果:对照组在5组中显示出最高的抗折力,用ANOVA和t检验显示其与各组间均有显著差异;树脂加强型玻璃离子组较其他实验组有更高的牙齿抗折力.结论:粘接银汞修复是一项有效的技术,用树脂加强型玻璃离子作粘接剂能更有效地提高牙体的抗折力,值得在临床推广应用.     

三种银汞合金黏结修复方法修复缺损后牙冠抗裂强度的比较

目的 评价三种不同的银汞黏接剂应用于黏接银汞修复时,修复后牙冠的抗裂强度的差异.方法 选40颗因正畸需要拔除的新鲜上颌第一前磨牙,在牙合面制备近远中三面洞形,分为4组(直接银汞充填组;树脂加强型玻璃离子水门汀组;玻璃离子水门汀组;树脂型银汞黏接剂组).样品在37℃水浴72h,5℃到55℃水浴循环2500次,然后用振动动态测试系统进行抗折实验,记录时间.结果 ANOVA和T检验显示直接银汞合金充填组与其余各组间均有显著差异,树脂加强型玻璃离子组与树脂型银汞黏接剂组较其他实验组有更高的牙冠抗折力.结论 黏接银汞修复是一项有效的技术,并且用树脂加强型玻璃离子作黏接剂能更有效地提高牙冠的抗折力,值得在临床推广应用.     

Microleakage and SEM interfacial micromorphology of amalgam restorations using three adhesive systems

OBJECTIVE: This study evaluated the microleakage and interfacial micromorphology of Class V cervical amalgam restorations lined with OptiBond, AElitebond, or Panavia 21. METHODS: Unlined amalgams served as control. Cavities were treated with each dentin bonding system according to the manufacturers' instructions and restored with Tytin non-gamma 2 spherical amalgam. After one week of storage in tap water at 37 degrees C, the specimens were thermocycled (1000 cycles, 6-60 degrees C, 30s dwell time). Microleakage was assessed by means of basic fuchsin dye penetration and recorded according to an ordinal scale. RESULTS: None of the systems tested in this study completely eliminated microleakage. Kruskal-Wallis one-way ANOVA and Mann-Whitney U test found that on the occlusal wall, Panavia 21 and the control group had the least leakage (P<0.05). No statistically significant differences were found at dentin margins (P>0.05). Wilcoxon matched pairs signed rank test found that Panavia 21 and the control group had less leakage at the occlusal than at the dentin margins (P<0.05); when AElitebond and OptiBond groups were evaluated, microleakage at the enamel and at the dentin margins was similar for each group. With the adhesive systems, perhaps the hydrophilic bonding agents incorporated the dye during specimen immersion and/or sectioning. CONCLUSIONS: The use of adhesives may not be as worthy as resin cements for sealing and bonding amalgam restorations to enamel and dentin.     

Microleakage of bonded amalgam restorations: effect of thermal cycling

This study examined the effect of thermal cycling on the microleakage of bonded amalgam restorations. Three dental amalgam alloys and a gallium alloy were tested with two adhesive resin systems and copal varnish as a control. Class V cavity preparations were prepared on 168 freshly extracted premolars or molars. The preparations were placed parallel to and 1.0 mm occlusal to the cementoenamel junction (CEJ). Four groups of 42 teeth each were treated with one of the following adhesive dentin systems: Bond-It, All-Bond 2/Resinomer or a copal varnish (Copalite). The four groups of 42 teeth each were then restored with one of three dental amalgams: Orosphere Plus, Indiloy, Oralloy or a Gallium alloy (Galloy), resulting in 12 test groups of 14 teeth each. The specimens were stored in double distilled water at 37 degrees C for 24 hours. Final contouring and polishing of the restorations were performed under water spray. Half of the restorations in each group were thermocycled for 3000 cycles (5 degrees C-37 degrees C-55 degrees C-37 degrees C) with a dwell time of 15 sec at each temperature. The other half were stored in double distilled water at 37 degrees C for 24 hours. Then all 168 restorations were stained with dye, sectioned and scored for microleakage. Results showed that the adhesive dentin systems reduced microleakage in amalgam restorations compared to copal varnish only in non-thermocycled specimens. Statistical analysis of the results showed that there was an extremely significant difference (p < 0.001) in microleakage between the non-thermocycled and the thermocycled specimens in all test groups, whereas, there was no significant difference (p > 0.05) among thermocycled specimens. The reduction of microleakage was not significantly different between Bond-It and All-Bond 2/Resinomer in non-thermocycled specimens. Oralloy showed the most microleakage in the non-thermocycled groups when compared to the other alloys using the same adhesive liner.     

Microleakage in conventional and bonded amalgam restorations: influence of cavity volume

This study verified the relationship between the volume and microleakage of conventional and bonded amalgam restorations. Also, the microleakage influence of intermediate materials, substrates and the direction of sectioning was investigated. Fifty-six bovine incisors were selected. Standard Class V cavities were prepared in buccal and lingual surfaces. For each tooth, two cavity sizes were prepared, corresponding to two cavity volumes: one larger (A) and the other smaller (B). The cervical wall was located in cementum/dentin and the incisal wall in enamel. The teeth were distributed in four groups (n=28) according to the intermediate material employed (glass-ionomer cement, resin cement, adhesive system and copal varnish-control). The materials were applied following manufacturers' directions. After restoration, the teeth were submitted to thermal cycling. They were then immersed in a dye solution and sectioned in two directions inciso-cervical (IC) and mesio-distal (MD) sections to evaluate the microleakage. Data were subjected to non-parametric statistical analysis (Wilcoxon's paired test and Kruskal-Wallis test). No significant difference was found between the two cavity sizes. Leakage in enamel was statistically lower than in the cementum/dentin interface (p < 0.05). In some situations, glass-ionomer or resin cement lined amalgam restorations presented less dye leakage than copal varnish lined restorations (p < 0.05). No significant difference was observed in microleakage between IC or MD sectioning. Within the limitations of this study, it was concluded that cavity size and direction of section were not significant factors for microleakage, while substrate and intermediate materials had a significant effect on the sealing ability in amalgam restorations.     

不同粘接系统联合银汞充填窝洞后牙体抗力的实验研究

目的 比较研究不同的粘接系统应用于银汞合金充填后,对牙体折裂强度的影响.方法 48颗完整上颌第一前磨牙,随机分为4组,A组为完整牙齿,B、C、D组经制备MOD标准洞型后,分别采用银求合金直接充填、全酸蚀粘接剂联合银汞合金充填和自酸蚀粘接剂联合银汞合金充填.所有试件充填完成后,在电子万能试验机上.以横梁位移速率1.0 mm/min垂直于(牙合)面加载,记录牙齿折裂的最大折裂强度并行统计学分析.结果 4组试件的折裂强度(N)依次为1064.9±202.8、549.1±70.2、928.7±135.2和858.9±133.2.与银汞合金直接充填相比,采用粘接剂的两组试件折裂强度显著增强(P＜0.01);但不同粘接剂组间比较未见明显差异(P＞0.05).结论 在使用银汞合金充填窝洞前,辅助使用全酸蚀或自酸蚀粘接剂,均可显著提高牙体的折裂强度.     

银汞合金粘结修复的临床应用研究

目的 :探讨银汞合金粘结修复的临床疗效。方法 :将 12 0例 2 0 4个后牙邻面龋或邻牙合面龋患牙随机分为两组 ,分别采用银汞合金粘结修复和常规银汞充填修复。结果 :银汞合金粘结修复组和常规银汞充填组 1年后复查 ,临床修复效果无显著性差异 ,2～ 3年后复查 ,两组间疗效有显著性差异 (P <0 .0 5 )。结论 :银汞合金粘结修复可明显提高修复体的固位力 ,是一种极具临床应用前景的修复方法     

Effect of adhesive volume on the bond strength of bonded complex amalgam restorations

PURPOSE: To evaluate in vitro the effect of adhesive volume on the bond strength of bonded complex amalgam restorations using Amalgambond Plus with HPA powder. METHODS: Standardized 6 mm-diameter dentin cylinders were prepared from 30 extracted human molar teeth. Specimens were divided into two groups (n=15). Group 1 received a minimal volume (5 microl) of Amalgambond Plus with HPA powder and Group 2 received a surplus volume (10 microl) of Amalgambond Plus with HPA powder. Amalgam restorations were placed, and loaded at 45 degrees to the long axis of the tooth using an Instron testing machine. RESULTS: Group 1: 14.71 (+/- 3.41) MPa, Group 2: 15.67 (+/- 3.72) MPa. A Student's t-test indicated no significant difference between the groups (P> 0.05).     

Microleakage evaluation in amalgam restorations used with bases.

Marginal leakage in amalgam restorations often precedes the development of secondary caries. One potential way to improve the marginal seal of such restorations, and thus minimize the risk of caries development, is to apply a glass-ionomer base prior to amalgam placement. This study compared microleakage resistance among amalgam restorations placed with and without light-cured glass-ionomer base materials. Preparations were made in extracted human molar teeth. Four groups were studied, including copal varnish, which was used as a control. All specimens were restored with amalgam. Results indicated significantly greater leakage at the cavity wall/base interface for restorations with a copal varnish cavity liner than for those with a glass-ionomer base. Leakage differences among bases were also found at the amalgam/base interface. Best results were obtained with a dual-cure resin-based system. These samples showed minimal leakage at both the cavity wall/base and the base/amalgam interfaces. These findings suggest that light-cured glass-ionomer bases can be effective in the prevention of microleakage in amalgam restorations.     

Microleakage of amalgam restorations with high-copper content.

An in vitro study of microleakage of the margins of Class II restorations of several high-copper-content amalgams found that in general, leakage increased between 24 hours and a month, but decreased below the 24-hour values after six months; there were some differences in leakage among the products at 24 hours, but not aftersix months: the depth of leakage was not correlated with adaptation of the cavosurface margins; and the high-copper-content amalgams were similar to the conventional composition amalgam tested in regard to microleakage.     

Microleakage effect on class V composite restorations with two adhesive systems using different bleaching methods

Abstract

Objective. The main objective of this study was to evaluate the effects of an at-home and two in-office (chemically activated and KTP laser-activated) bleaching methods on the microleakage of composite resin restorations bonded with etch-and-rinse and self-etch adhesive systems. Materials and methods. Class V cavity preparations were performed on 96 premolars and teeth were divided into two groups according to the two adhesive systems (etch-and-rinse and self-etch). After cavities were restored with an adhesive systems and composite resin, they were submitted to thermocycling procedures. Teeth were divided into four sub-groups according to the bleaching systems (control, at-home bleaching, chemically activated office bleaching and KTP laser-activated office bleaching). After the bleaching procedure, teeth were evaluated for marginal leakage. All data were analyzed using the Mann-Whitney U and Kruskal-Wallis tests (p < 0.05). Results. The results of the present study showed that the control group presented lower microleakage values compared with the groups treated with bleaching agents, except for the chemically activated in-office bleaching. When the scores of microleakage at the enamel and gingival margins of the four groups were compared, the differences among the groups were found to be statistically significant (p < 0.05). Comparing the gingival and enamel margins in each group, statistically significant differences were found in the at-home group (p < 0.05) and no significant differences were seen in the other groups (p > 0.05). No significant difference was found between the adhesive systems after treatment with the same bleaching techniques. Conclusion. Under the conditions of this study, microleakage of composite resin restorations differs according to the bleaching methods used and no difference was found between the adhesive systems.     

Microleakage in alloy-glass ionomer lined amalgam restorations after thermocycling

Marginal microleakage was measured around amalgam restorations lined with alloy-glass ionomer cement and coated with a glass ionomer varnish. Preparations were made in 48 human extracted mandibular molar teeth. Alloy-glass ionomer liners and varnishes were placed into selected preparations. Tytin amalgam was inserted into all of the teeth and left unburnished and unpolished. Half of the total samples were thermocycled for 5 days and the remainder were left in deionized water. The teeth were immersed in a 0.5% methylene blue dye and sectioned vertically with a diamond saw. Microleakage was scored visually at x100 magnification, and the data were analysed using the Mann-Whitney U-test (P less than or equal to 0.05). Thermocycling did not have a significant effect on microleakage, except when both an alloy-glass ionomer liner and varnish were used. Overall, the use of an alloy-glass ionomer liner made the most significant difference in reducing microleakage.     

Effect of bonded amalgam restorations on microleakage

The purpose of this study was to evaluate quantitatively the effectiveness of adhesive dentin bonding systems in decreasing microleakage at the tooth-amalgam restoration interface. The results indicated that microleakage was significantly reduced when Amalgambond Plus or All-Bond 2 was used as liners in comparison to either Copalite varnish or no linear under amalgam restorations. No significant difference was found between the two dentin bonding systems at all time periods studied.     

Microleakage of temporary endodontic restorations in teeth restored with amalgam

Microleakage of seven temporary restorative materials was evaluated in endodontic access preparations made in teeth restored with amalgam. Ten teeth were used for each of the seven materials: Cavit, Cavit-G, TERM, zinc phosphate cement, polycarboxylate cement, glass ionomer cement, and IRM. A class I amalgam was placed in the occlusal surface of each experimental tooth and an endodontic access preparation was made entirely within the amalgam. Then the access preparation was restored with one of the temporary restorative materials, and microleakage was evaluated using a fluid filtration technique. The amount of microleakage was quantitated by measuring the fluid flow at 15 min, 1 h, 24 h, 1 wk, and 2 wk after insertion of the temporary restoration. Cavit, Cavit-G, TERM, IRM, and glass ionomer cement all provided excellent seals while zinc phosphate cement and polycarboxylate cement provided less effective seals.