Effect of adhesive systems and bevel on enamel margin integrity in primary and permanent teeth

PURPOSE: This study compared the effectiveness of self-etch and total-etch adhesive systems in bonding to the beveled and nonbeveled margins of primary and permanent teeth. METHODS: This in vitro, factorial-designed study allowed evaluation of 3 factors: (1) tooth type; (2) presence of a bevel; and (3) adhesive type. Two preparations, each including a beveled and nonbeveled margin, were completed on buccal surfaces of 60 extracted molars (30 primary and 30 permanent). Preparations were randomly assigned to self-etch or a total-etch adhesive system and restored with resin composite. After thermocycling, teeth were stained with silver nitrate, sectioned, and measured for microleakage. Statistical analysis used a repeated measures analysis of variance. RESULTS: Beveled margins had less microleakage than nonbeveled margins for primary and permanent teeth (P < .001). Total-etch had less microleakage than self-etch adhesives on primary (53% less, P < .001) and on permanent teeth (22% less, P = .01). Self-etch had considerably more microleakage when enamel margins were not beveled. Comparably less microleakage, however, was found for total-etch and self-etch in restorations with beveled margins. CONCLUSIONS: Total-etch adhesive and beveled margins resulted in the least microleakage. Margin beveling has a greater effect in minimizing microleakage than the type of adhesive used.     

Marginal opening of single and twin platinum foil-bonded aluminous porcelain crowns

The marginal openings of single and twin foil-bonded aluminous porcelain crowns were compared in crowns fabricated indirectly for extracted teeth and directly on typodont teeth. The crowns were cemented with zinc phosphate, embedded in plastic, and sectioned. Marginal opening was measured directly with a traveling microscope. There was no significant difference between the marginal openings of twin- and single-foil crowns fabricated indirectly for extracted teeth. When the crowns were constructed directly on typodont teeth to eliminate the variables of impression-making and die fabrication, the single-foil crowns possessed a significantly smaller marginal opening than the twin-foil crowns. Both the twin- and single-foil complete porcelain crowns resulted in clinically acceptable margins. The single-foil crowns were easier to make.     

Invisible supragingival crown margins: an in vitro study

A method of improving the esthetics and seal of porcelain crown margins using composite resin is described. The procedure includes a circumferential shoulder-type preparation located entirely in enamel. To provide adequate space for a thin layer of composite resin to blend gradually into both tooth enamel and porcelain surfaces, the cervical enamel as well as the opposing porcelain butt joint are subsequently beveled. In this study, microleakage analysis and SEM evaluation of the marginal area indicate that the marginal design described can predictably produce an optimal esthetic appearance and marginal seal, contour, and integrity with supragingival ceramic restorations.     

3种冠边缘肩台设计对龈沟液中IL-1β、AST及其OPN水平的影响

目的：探讨烤瓷熔附金属全冠不同冠边缘设计对龈沟液中自细胞介素117（IL-1B）、天冬氨酸转氨酶（AST）和骨桥蛋白（OPN）水平的影响,为临床修复设计提供合适的边缘修复。方法：选择拟行固定冠修复的病例32例,均为上颌前牙56颗,分别设计不同的冠边缘修复设计,行镍铬合金烤瓷全冠修复。在修复前、修复后1、3、6、12个月分别检测、分析牙周临床指标,及应用ELISA法和全自动生化分析仪测定龈沟液（gingivalcrevicularflu-idGCF）中IL一1口、AST、OPN的含量。结果：3组修复设计修复6个月后牙周临床指标和龈沟液中的细胞因子、酶类的水平变化量明显增加,差异具有统计学意义（P％0．05）,后期随着修复时间的延长变化量趋于平稳。3组之间相比：B组的牙周临床指标和龈沟液中的各项指标表达量明显小于A、C组,差异具有统计学意义（P％0．05）。结论：镍铬合金烤瓷修复全冠无论何种冠边缘修复设计都会对牙周产生不良刺激,但是带斜面的浅凹形肩台组对牙周的刺激由于直角肩台组合刃状边缘组。     

Optical behavior of current ceramic systems

The restoration of anterior teeth is a difficult task, even for an experienced operator. Currently there are many different ceramic systems that can be used to achieve highly esthetic results. These include metal-ceramics with porcelain margins, Dicor, In-Ceram, Cerestore, Hi-Ceram, IPS-Empress, Cerapearl, Optec, and CAD/CAM ceramics. While metal-ceramics have been used for more than four decades, the quest for a material that transmits and refracts light like a natural tooth has inspired research into all-ceramic restorations. The purpose of this paper is to briefly discuss the properties of each of the above-mentioned materials and clinically evaluate the optical behavior of: (1) metal-ceramic crowns with castings 2 mm short of the shoulder preparation and 360-degree porcelain margins; (2) In-Ceram Spinell restorations; and (3) IPS Empress restorations, and to compare these with metal-ceramic crowns with copings to the shoulder preparation and 180-degree porcelain margins. Light transmission characteristics and color matching were subjectively evaluated by five experienced prosthodontists who did not participate in this clinical study.     

Marginal integrity of large compomer Class II restorations with cervical margins in dentine

OBJECTIVES: The aim of the present study was to investigate the marginal integrity of total-bond Dyract AP restorations in large Class II restorations with cervical margins in dentine. The efficacy of a new non-rinse conditioner and the effect of beveling the enamel margins were also studied. METHODS: Large MOD cavities with cervical margins located 1mm below the CEJ were prepared in 48 extracted human molars. Six groups (n=8) were filled using a total-bond technique with Spectrum TPH or Dyract AP or a sandwich technique with Dyract in combination with Spectrum TPH. For Dyract AP total-bond restorations, a new non-rinse conditioner was tested vs. a total-etch with 36% phosphoric acid in beveled and butt-joint cavities. After water storage for 21 days and thermocycling (2000x, 5-55 degrees C), replicas were produced for quantitative marginal analysis in the SEM. Afterwards, teeth were immersed in 0.5% basic fuchsin for 24h and dried. Percent dye penetration over the total margin length was analysed in three layers using a sequential grinding technique. Statistical analysis was performed with non-parametric tests and the Bonferroni correction for multiple comparisons at p<0.05. RESULTS: All restoration types showed microleakage. On cervical margins in dentine, Dyract AP restorations showed better marginal adaptation than Spectrum TPH total-bond restorations (marginal openings (MO), median 33.8 vs. 79.6%), but were inferior to Dyract/Spectrum TPH sandwich restorations (MO: 0. 0%). The non-rinse conditioner improved the marginal adaptation of Dyract AP restorations in dentine (MO: 4.7 vs. 38.4%, p=0.0206 for beveled cavities, 12.2 vs. 33.8%, p=0.0238, for butt-joint cavities) and yielded similar results in enamel margins provided that enamel margins were beveled. Beveling of enamel significantly reduced the occurrence of enamel microcracks. CONCLUSIONS: The use of a non-rinse conditioner in combination with Dyract AP may improve the marginal adaptation of Class II restorations compared to composite restorations. The sandwich technique with Dyract results in better marginal adaptation in cervical dentine compared to all other restorative techniques tested in this study. However, microleakage cannot predictably be prevented with the sandwich technique.     

Microleakage of Porcelain and Composite Machined Crowns Cemented with Self‐Adhesive or Conventional Resin Cement

Purpose: Resistance of machined crowns to microleakage when cemented with new self‐adhesive cements has not been fully investigated. This study evaluated microleakage of machined crowns milled from porcelain and composite blocks and bonded to teeth with self‐adhesive and conventional resin cement. Materials and Methods: Thirty‐two freshly extracted premolars of similar shape and size were sterilized and mounted in resin blocks. Teeth received standard crown preparations with 1‐mm circumferential shoulder finish line, flat occlusal surface reduced by 2 mm, and ideal angle of convergence. Prepared teeth were divided into two equal groups and assigned to either porcelain (Vita Mark II, Vident) or composite (Paradigm MZ100, 3M ESPE) blocks for crown fabrication. Optical impressions were captured for each tooth with the intraoral camera of a CEREC 3D machine. Crowns were designed and milled from both materials. Each group was then subdivided into two subgroups (n = 8) according to cement used (self‐adhesive resin cement, RelyX Unicem, 3M ESPE or resin cement with self‐etching adhesive, Panavia F 2.0, Kuraray). Following seating, a 5‐kg weight was applied on the occlusal surface of the crown for 5 minutes. Specimens were then stored in water at 37°C for 24 hours. Specimens were thermocycled for 3000 cycles between 5°C and 55°C, then coated with nail varnish and immersed in a 2.0% basic red fuchsine dye solution for 24 hours. Teeth were then rinsed and sectioned mesiodistally and assessed under magnification for microleakage. A five‐point scale was used to score degree of microleakage. Data were statistically analyzed with 2‐way ANOVA and Kruskal‐Wallis nonparametric test. Results: Crown material had no significant effect on microleakage (p= 0.67); however, cement type had a significant effect (p < 0.0001), with Panavia F 2.0 resulting in lower microleakage scores than RelyX Unicem. Conclusions: Compared to the self‐adhesive cement, the resin cement with separate primer/bonding agent resulted in significantly lower microleakage scores, irrespective of crown material.     

计算机辅助设计和制造全瓷冠在前牙修复的临床效果

目的比较计算机辅助设计和制造全瓷冠与钴铬合金烤瓷冠在前牙修复的临床效果。方法采用计算机辅助设计和制造技术制作89件前牙二氧化锆全瓷冠,采用钴铬合金烤瓷冠制作67件前牙修复体,修复后1年复查,对边缘着色、龈缘密合度、修复体颜色、修复体周围龋、修复体折裂、牙龈健康情况进行评价。结果在边缘着色、龈缘密合性、修复体颜色、牙龈健康状况方面差异有统计学意义(P<0.05),全瓷冠的临床效果优于钴铬合金烤瓷冠。结论计算机辅助设计和制造全瓷冠的临床修复效果良好,是前牙修复的理想选择。     

Influence of luting agent on the microleakage of all-ceramic crowns

PURPOSE: In this in-vitro study, microleakage of all-ceramic crowns was evaluated at enamel and dentin margins. MATERIALS AND METHODS: Forty maxillary central incisors were randomly divided into 4 groups (n = 10). While buccal and palatal margins were placed on enamel, mesial and distal margins were placed below the cementoenamel junction. In groups 1 to 3, IPS Empress 2 crowns were luted with Variolink 2/Syntac Classic (group 1), Bifix DC/Solobond Plus (group 2) and Calibra/Prime & Bond NT combinations (group 3), respectively. In the control group (group 4), porcelain-fused-to-metal crowns were luted with a zinc-phosphate cement. All specimens were subjected to 5000 thermocycles (at 5 degrees C to 55 degrees C; 30-s dwell time). After immersion in India ink for 48 h at 37 degrees C, the specimens were sectioned both buccolingually and mesiodistally. Each section was evaluated for microleakage under a stereomicroscope at 24X magnification. RESULTS: According to the Krukal-Wallis test, in all groups, there were significant differences in microleakage at the enamel margins (p = 0.001). Nevertheless, the margins finished in dentin showed no significant differences (p = 0.163). According to the Mann-Whitney U-test, statistically significant differences were observed in microleakage between groups 1 and 3 (p = 0.049), groups 1 and 4 (p = 0.001), groups 2 and 4 (p = 0.002), and between groups 3 and 4 (p = 0.045) at the enamel margin. In group 1, significantly greater microleakage was observed at the dentin margin compared to the enamel margin (p = 0.007). CONCLUSION: The adhesive luting technique demonstrated an excellent ability to minimize microleakage of all-ceramic crowns at the enamel margins. Water-based dentin bonding systems showed less microleakage than the water-free acetone-based dentin bonding system at the enamel margin.     

Marginal fidelity and microleakage of porcelain veneers made by two techniques.

This study evaluated the marginal fidelity and microleakage of porcelain veneers made with the platinum foil and refractory die techniques. Maxillary incisors, matched for size and amount of enamel, were prepared with 0.5 mm uniform intraenamel reduction. The indirectly made veneers were etched, treated with silane, and luted with a composite resin, and the margins were finished and polished. The restored teeth were stored in 37 degrees C water, thermocycled 1000 times, stained with silver nitrate, embedded, sectioned buccolingually and mesiodistally, and measured at x250 magnification. The platinum foil veneers had significantly better vertical marginal fidelity but significantly more overcontouring than had the refractory die veneers. Universal microleakage at the tooth-composite resin interface and negligible microleakage at the porcelain-composite resin interface were observed. No relationship was found between the amount of vertical marginal opening and the amount of microleakage.     

疲劳循环对复合树脂微渗漏影响的体外研究

目的:通过体外加载实验观察复合树脂边缘微渗漏变化情况,分析洞缘斜面的必要性。方法:将140颗离体牙按是否制备洞缘斜面、不同疲劳循环加载次数及位点随机分为14小组。所有样本采用复合树脂(3M P60)充填,包埋后经不同疲劳循环次数(0、1×10⁵、1.3×10⁶次)或加载位点(颊尖、颊界面、修复体)进行加载试验,检测修复体界面染料渗透深度。结果:1.3×10⁶次组微渗漏大于1×10⁵次及0次组。0次加载时,不同洞缘组间差异不显著;加载1×10⁵次后,牙体受力时洞缘斜面组的微渗漏比无洞缘斜面组小(P<0.05);加载1.3×10⁶次后,洞缘斜面组微渗漏小于无洞缘斜面组(P<0.05)。结论:体外疲劳循环(模拟咀嚼半年)后,洞缘斜面有利于减少复合树脂的微渗漏。     

Fit of three porcelain-fused-to-metal marginal designs in vivo: a scanning electron microscope study

This study examined the comparative fit in vivo of three types of PFM crown margins. Marginal openings were measured with an SEM on replicas derived from elastomeric impressions. There was no significant difference among beveled metal margins, metal butt margins, or porcelain butt margins either before or after cementation at the 95% confidence level. This study has shown that it is possible under clinical conditions to consistently produce porcelain butt margins with less than 50 micron marginal opening in PFM restorations.     

Marginal adaptation and microleakage of Procera AllCeram crowns with four cements

PURPOSE: This study investigated the effect of different cements on microleakage and marginal adaptation of porcelain crowns. MATERIALS AND METHODS: Eighty extracted molars were divided into two groups. Teeth in one group were prepared to receive Procera AllCeram crowns, whereas the other group was prepared to receive metal-ceramic crowns. Copings were made following standard techniques, and groups were divided for cementation with zinc phosphate, glass-ionomer, resin-modified glassionomer, or resin cement. Specimens were subjected to thermocycling prior to microleakage testing, then sectioned. Microleakage was scored using a five-point scale; marginal adaptation was assessed with a traveling microscope. RESULTS: A significant association was found between cement type and degree of microleakage. With zinc phosphate, 76% of Procera AllCeram and 90% of metal-ceramic copings exhibited extensive microleakage. With glass-ionomer, 49% of Procera AllCeram and 66% of metal-ceramic copings had 0 microleakage scores; with resin-modified glass-ionomer, 10% of Procera AllCeram and 84% of metal-ceramic copings had 0 microleakage scores. With resin cement, 34% of Procera AllCeram and 96% of metal-ceramic copings exhibited 0 microleakage. Procera AllCeram copings had a significantly larger mean marginal gap (54 microm) compared to metal ceramic (29 microm). CONCLUSION: In both types of crowns, the use of resin cement resulted in the highest percentage of 0 microleakage scores, whereas the zinc phosphate cement resulted in the highest percentage of extensive microleakage.     

Microleakage of all-ceramic crowns using self-etching resin luting agents

Self-etching adhesive systems are a new generation of materials that possess acidic methacrylates that can generate self-adhesion. There is limited data reported on the marginal leakage of ceramic restorations bonded with self-etching adhesive materials. This study assessed and compared the amount of microleakage of bonded ceramic crowns using three different types of self-etching adhesive systems with and without a die spacer. Eighteen human molars were prepared for all-ceramic IPS Empress crowns and the teeth were randomly assigned to each experimental group. The buccal side had the preparation finish line 1.5 mm below the CEJ, and the lingual finish line was 1.5 mm above the CEJ, creating margins in enamel and dentin. Two die-spacing techniques were used (three layers or no layer of die spacer). Each crown restoration was cemented with one of three self-etching resin luting agents (Panavia F 2.0, Multilink and RelyX Unicem). The specimens were thermally cycled for 1000 cycles, then immersed in a 5% methylene blue dye solution for 24 hours. The teeth were then rinsed, embedded in clear epoxy resin and sectioned. A total of 60 sections were evaluated for each type of resin luting agent using digital image analysis at 70x magnification. A novel formula, using mean percentage of microleakage, was developed by dividing the extent of dye penetration along the tooth/resin luting cement interphase and the total perimeter of the tooth crown surface. The data were analyzed using three-way analysis of variance at the 0.05 level of significance. Fisher's PLSD intervals were calculated for comparing significant means. Panavia F 2.0 showed a lower degree of microleakage than RelyX Unicem and Multilink at both the enamel and dentin margins. Interactions of the main effects (cement, margin and die spacer technique) were all highly significant (p< or =0.004). The degree of microleakage was higher on the dentin margins than on the enamel margins (p<0.0001). The degree of microleakage for the die spacer group was not significantly different from the group with no die spacer technique (p>0.1). Overall, Panavia F 2.0 showed the least microleakage, followed by RelyX Unicem and Multilink, respectively.     

Porcelain shoulder adaptation using direct refractory dies

Eleven direct refractory dies were made from separate polysulfide rubber impressions of two Dentoform teeth which had been prepared for porcelain-fused-to-gold veneer crowns with labial porcelain shoulders.Porcelain veneer crowns were built and fired directly on the dies, following the manufacturer's instructions and using a common laboratory technique.The finished crowns were seated on the Dentoform teeth, and the porcelain-tooth adaptation was measured with a micrometer eyepiece in a dissecting microscope.In general, the study indicated that by use of a direct refractory die, the porcelain adaptation of an average porcelain shoulder veneer crown could be made to fall within the tolerances of a clinically acceptable gold margin (39 μ).²¹ The crown could likewise be made to adapt closer than the normal thickness of cement film may allow (20 to 40 μ).²² However the adaptation of many crowns was more uneven than the above statements would tend to indicate.The study also showed that with great care and a limited number of firings, margins of a lesser thickness than a piece of 0.001 inch (25.4 μ) platinum foil could be attained.There appears to be promise in the use of a direct refractory die material. However, more studies are needed to overcome some of the problems in the technique described.     

Cement thickness and microleakage under Dicor crowns: an in vivo investigation.

This in vivo study recorded the microleakage and marginal discrepancies of cast glass-ceramic cemented crowns compared to gold onlays and a metal ceramic restoration. Within the limits of the small number of samples and the variables inherent in an in vivo study, it was found that (1) dentin bonding agents are not strong enough to produce a gap-free cementation, (2) the marginal adaptation of beveled metal restorations is better than that of glass-ceramic crowns, and (3) the marginal adaptation of cast glass-ceramic crowns is clinically acceptable.     

高度抛光无釉瓷氧化锆全瓷冠的临床效果研究

目的评估高度抛光无釉瓷氧化锆全瓷冠的临床效果。方法牙体缺损磨牙80颗,分为2组,40例40颗患牙进行高度抛光无釉瓷的氧化锆全瓷冠修复（试验组）,40例40颗患牙常规制作钯金烤瓷牙单冠修复（对照组）。戴固后即刻、3个月、6个月、12个月、24个月、36个月临床观察和评价修复体破损和对袷牙磨耗情况,比较2组修复体的存留率和成功率。结果试验组中有1件修复体出现小面积瓷裂,修复后12个月2件全瓷冠对冶天然牙牙出现I级磨耗。对照组中有3件修复体出现小面积瓷裂,但对殆天然牙均无明显磨耗。试验组和对照组修复体3年存留率分别为100％和97．5％,成功率分别为97．5％和90％,差异均无统计学意义（P〉0．05）。结论高度抛光无釉瓷氧化锆全瓷冠修复磨牙牙体缺损不易破损,对猞天然牙磨耗轻微,成功率高.     

Influence of porcelain material and composite luting resin on microleakage of porcelain laminate veneers

The microleakage beneath porcelain laminate veneers was investigated. The restoration margins were located according to the preparations made below or above CEJ of extracted maxillary central incisors. Vitadur N and Microbond porcelain materials were used to prepare laminate veneers. A light cured composite resin (Porcelite) and a light- and chemical-cured composite resin (Porcelite Dual Cure) were used as luting agents. The bonded specimens were thermocycled and by employing the standard dye penetration technique, the leakage was scored from cervical and incisal margins. Significantly greater microleakage was recorded at the dentine composite resin interfaces than at the enamel/composite interfaces. Statistically insignificant differences were observed with the use of the four cement/porcelain combinations studied.     

颈缘瓷在前牙烤瓷全冠修复中的美学效果

目的评价颈缘瓷在前牙镍铬合金烤瓷全冠修复中的临床美学效果。方法265例患者的527颗牙用金刚砂车针进行常规牙体及颈部肩台制备，用Ivoclar低温瓷粉制作具有颈缘瓷的镍铬合金烤瓷全冠。临床试戴、抛光、粘结。结果修复后随访1～4年，与具有颈缘瓷的镍铬合金烤瓷全冠相接触的牙龈未见龈缘灰线，约3％的患者有轻到中度龈炎。结论鉴于对牙龈组织的保护和牙龈及牙体美学的考虑，笔者认为在制作镍铬合金烤瓷全冠时，添加颈缘瓷是一个非常有效的修复方法。     

Composite restorations: influence of flowable and self-curing resin composite linings on microleakage in vitro

This in vitro study evaluated the microleakage at enamel (occlusal) and dentin (gingival) margins of MOD resin composite restorations made with different incremental insertion techniques. MOD cavities were prepared on 60 extracted human molars with the proximal margins placed 1 mm below the cemento-enamel junction. All teeth were acid-etched and treated with One-Step adhesive, then restored with a hybrid resin composite (Renew) with and without a flowable composite (AEliteflo) or a self-curing composite (Bisfil 2B) as the first increment in the proximal boxes. The time of placement of the second increment in relation to curing of the first increment was also varied. After polishing, the teeth were soaked in 0.5% basic fuchsin for 24 hours, sectioned and evaluated for dye penetration. None of the restorative techniques prevented microleakage at the enamel and dentin margins. However, microleakage at dentin margins were significantly reduced by the use of a flowable composite as the first increment in the proximal boxes. Time of placement in relation to curing had no influence on microleakage. Microleakage was lower at enamel margins than at dentin margins; however, besides microleakage at the enamel-restoration interface, 37 of the 60 restored teeth (62%) displayed at least one white line in enamel adjacent to the composite restoration.