Use of heat-pressed, leucite-reinforced ceramic on anterior and posterior onlays: a clinical report

The introduction of new techniques and materials in all-ceramic systems, together with improvements in resin bonding agents, has enabled the use of resin cements to directly bond ceramic crowns, veneers, and inlays/onlays to conservative tooth preparations. Directly bonded ceramic onlays can eliminate the need for conventional means of retention and allow the restoration of lost tooth structure with minimal tooth preparation. This article presents the use and short-term clinical performance of directly bonded, heat-pressed, leucite-reinforced ceramic onlays in both anterior and posterior areas of the mouth.     

前牙全瓷冠的循环疲劳特性及寿命分析

目的 分析全瓷冠(IPS Empres2)循环疲劳特性及寿命,为全瓷冠的临床设计、制作以及使用寿命的评估提供依据.方法 建立上中切牙及其全瓷冠的有限元模型,模拟牙尖交错(牙合)时前牙正常骀关系,在90～130 N静态载荷加载下,分析全瓷冠受力状况.根据有限元获得的应力、应变结果,使用MSC Fatigue疲劳分析软件在90～130 N循环载荷下研究全瓷冠的循环疲劳特性及寿命.结果全瓷冠唇舌侧颈部肩台为疲劳寿命最短的区域,可承受的疲劳循环次数为2 506 109～6 950 243次.前牙承担的载荷逐渐增加时,全瓷冠疲劳寿命明显降低.前牙咬合接触时间增加时,全瓷冠疲劳寿命也逐渐降低.结论全瓷冠修复对全瓷材料循环疲劳性能有较高的要求,(牙合)力对全瓷冠疲劳寿命的影响大于咬合接触时间的影响,临床应注意合理调整全瓷冠所承担的(牙合)力.     

All-ceramic crowns: bonding or cementing?

Despite the wide variety of all-ceramic systems available today, the majority of dental practitioners hesitate to recommend and insert all-ceramic crowns. This article regards the nature of the ceramic materials, the principles of bonding and adhesion, and the clinical problems of the acid-etch technique for crowns. Advantages and disadvantages are discussed, and the influences of different factors on the strength of all-ceramic crowns are presented. Finally, the conclusion is drawn that conventional cementing of all-ceramic crowns is possible when the specific properties of the ceramics are taken into consideration.     

The influence of design parameters on the FEA-determined stress distribution in CAD-CAM produced all-ceramic dental crowns.

INTRODUCTION: Knowledge of factors, which influence stress and its distribution is of key importance to the successful production of durable all-ceramic restorations. The objective of this study was to evaluate, by finite element analysis (FEA), the influence of the shape of the preparation and the cement layer on the stress distribution in CAD-CAM produced all-ceramic crowns and in their cement layer. MATERIAL AND METHODS: The CAD models of multi-layer all-ceramic crowns for posterior tooth 46 of three patients produced with CAD-CAM-technology were translated into a three-dimensional FEA program. The stress distribution due to the combined influences of bite forces, residual stresses caused by the difference in expansion coefficient of the two ceramic layers, and the influence of shrinkage of the cement was investigated. RESULTS: The tensile stresses in the crown for the chamfer knife-edge preparation might put the integrity of the currently available ceramic materials at risk, while a non-uniform cement layer might result in stresses exceeding the bond strength. It was concluded that for long lasting restorations in the posterior region it is advisable to make a chamfer with collar preparation, the cement layer as uniform, and the difference in thermal expansion for the two ceramics as small as possible. SIGNIFICANCE: This study indicates that for full ceramic crowns in the posterior region, specific design rules should be followed, and that FEA utilizing CAD-CAM data can be a successful tool to develop design guidelines for all-ceramic restorations.     

Retrospective assessment of 546 all-ceramic anterior and posterior crowns in a general practice

STATEMENT OF PROBLEM: There is need to determine whether following a consistent procedural protocol in a private dental practice will result in high success rates for all-ceramic anterior and posterior crowns fabricated from aluminous porcelain veneered to high-alumina content-supporting cores. Aluminous porcelain is known to have poor tensile strength and fracture resistance when subjected to shear forces. PURPOSE: This study examined the long-term survivability of alumina core, all-ceramic crowns in both anterior and posterior locations. MATERIAL AND METHODS: Following a consistent protocol over 6 years, 546 all-ceramic, In-Ceram crowns (32.4% anterior [n = 177] and 67.6% posterior [n = 369]) were consecutively luted with glass ionomer resin hybrid cement and periodically observed by the same dentist who prepared and cemented them. RESULTS: The overall success rate was 99.1% (n = 541) with a 0.9% (n = 5) failure rate. The success-to-failure ratio for anterior all-ceramic crowns was 98.9% to 1.1% (n = 175:2); the posterior crown ratio was 99.2% to 0.8% (n = 366:3). CONCLUSION: Following a consistent protocol of careful tooth preparation and crown cementation resulted in high success rates for anterior and posterior all-ceramic crowns. Glass ionomer resin hybrid cement appeared to be a reliable luting agent. All-ceramic alumina core crowns are durable and provide optimum esthetic choices for anterior and posterior locations.     

Design of preparations for all-ceramic inlay materials

Because of the developments in the field of all-ceramic materials, which have quite different material properties compared with traditional materials for prosthetic treatment, it was also important to adapt the preparation to the new circumstances. Practiced design guidelines for the restorative treatment of teeth for all-ceramic restoration are illustrated in this article. Based on traditional retentive preparation shapes, modifications of these geometries "designed for ceramics" were developed and postulated. Despite excellent 15-year long-term results, it is important to draw the appropriate conclusions from failures that have occurred. The geometry of the cavities for all-ceramic inlays must be matched much more to the material-specific properties of hard and brittle restoration materials. Cavities designed for ceramics must therefore have the simplest possible basic geometry. Because of adhesive bonding, a retentive shape of the preparation is not necessary. Previous ceramic inlay designs must be redefined to achieve an increase in the fracture resistance of the ceramic.     

Fracture strength of all-ceramic crowns luted using two bonding methods

STATEMENT OF THE PROBLEM: Excellent esthetic quality is one of the major advantages of all-ceramic restorations; however, catastrophic fracture of such restorations is still a disadvantage. Ceramic bonding systems using ceramic primers without the use of hydrofluoric acid have been introduced, but data about the efficiency of these systems are lacking. PURPOSE: This study investigated the influence of 2 bonding procedures on the fracture resistance of low-fusing ceramic and computer aided design-computer aided manufacturing (CAD-CAM) all-ceramic crowns. MATERIAL AND METHODS: Forty-two standardized all-ceramic crowns were fabricated on human maxillary premolars. Seven unprepared maxillary premolars were used as control. Three all-ceramic crown systems were used: 1 low-fusing ceramic (Duceram) and 2 machineable ceramics (Vita Mark II and ProCAD) using the Cerec 3 CAD-CAM system. The intaglio surfaces of fabricated crowns (n=7) were subjected to 2 different conditioning techniques: etching, using 4.9% hydrofluoric acid followed by application of Mirage ABC silane, or cleaning, using 65% phosphoric acid and application of primer (Porcelain Liner-M). The crowns were luted to the teeth using Superbond C&B luting agent. After 24 hours storage in water, specimens were loaded in a universal testing machine with the compressive load applied along the long axis of the specimen at a crosshead speed 1 mm/min until fracture. Fracture loads (N) were recorded. One-way analysis of variance (ANOVA) and the Tukey HSD test (alpha=.05) were used for statistical analysis of the data. RESULTS: The mean fracture load of control specimens (738.3+/-195.3 N) was not significantly different from that of the 2 CAD-CAM crowns (667.7+/-72.3 N, 715.9+/-105.2 N). However, fracture load of natural teeth and the 2 CAD-CAM crowns was significantly higher than the fracture load of the low-fusing ceramic crowns treated with HF acid and silane (465.5+/-101.1 N) and, when cleaned, using phosphoric acid and an application of primer (447.5+/-63.4 N) (P<.05). There was no significant difference in the mean fracture load of each ceramic material when bonded using the 2 different procedures, either treated with HF acid and silane or cleaned using phosphoric acid and application of primer (P>.05). CONCLUSION: The application of a primer (Procelain Liner-M) was an effective method for treating the intaglio surface of all-ceramic crowns before cementation.     

Predictable aesthetic replacement of a metal-ceramic crown using CAD/CAM technology: a case report

The currently available CAD/CAM technologies present clinicians with various clinical benefits that include durability, marginal adaptation, and precision aesthetics. The clinical and laboratory procedures associated with these CAD/CAM systems differ from one another, and practitioners must understand the indications for each. Office-based systems, as demonstrated in the following case presentation, allow excellent results to be achieved in a single patient visit and provide a viable alternative for today's practice. This case report describes the associated sequences for a posterior CAD/CAM restoration. Learning Objectives This article discusses a protocol for the use of CAD/CAM restorations in the aesthetic replacement of defective posterior crowns. Upon reading this article, the reader should have: * Greater understanding of the in-office CAD/CAM procedures used to fabricate single-visit crowns. * Improved awareness of the bonding protocol used for these all-ceramic crowns.     

Bonding all-ceramic restorations with two resins cement techniques: a clinical report of three-year follow-up

Ceramics have been widely used for esthetic and functional improvements. The resin cement is the material of choice for bonding ceramics to dental substrate and it can also dictate the final esthetic appearance and strength of the restoration. The correct use of the wide spectrum of resin luting agents available depends on the dental tooth substrate. This article presents three-year clinical results of a 41 years old female patient B.H.C complaining about her unattractive smile. Two all-ceramic crowns and two laminates veneers were placed in the maxillary incisors and cemented with a self-adhesive resin luting cement and conventional resin luting cement, respectively. After a three-year follow-up, the restorations and cement/teeth interface were clinically perfect with no chipping, fractures or discoloration. Proper use of different resin luting cements shows clinical appropriate behavior after a three-year follow-up. Self-adhesive resin luting cement may be used for cementing all-ceramic crowns with high predictability of success, mainly if there is a large dentin surface available for bonding and no enamel at the finish line. Otherwise, conventional resin luting agent should be used for achieving an adequate bonding strength to enamel.     

CAD/CAM氧化锆全瓷冠修复临床疗效评价

目的：探讨CAD／CAM氧化锆全瓷冠的修复效果。方法：选择82例（192颗患牙）,分别在CAD／CAM氧化锆全瓷冠粘接后1、3、6、12个月进行随访观察。采用美国公共健康协会的修订标准对修复体的临床效果进行评价。结果：观察期间失访4例,随访78例共181件修复体,结果显示CAD／CAM全瓷冠颜色达到好以上91．2％,CAD／CAM氧化锆全瓷冠的崩瓷率2．76％,与修复体部位有明显相关性（P〈0．01）,在粘接12个月后有1个修复体的边缘密合度欠佳,所有复诊患者在12个月的临床观察中均未见边缘着色,继发龋和基牙松动。结论：氧化锆全瓷修复体具有良好的稳定性和生物相容性,近期临床效果满意。     

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。     

The 7/8 Crown: A Lost Art

SUMMARY Historically, the longevity of teeth restored with gold inlays, onlays, crowns, and partial veneer restorations is excellent. However, in-office computer-aided design and computer-aided manufacturing restorations, laboratory-constructed all-ceramic bonded restorations, and conventional ceramo-metal restorations are more common. The high price of gold, the difficulty of the preparation, and the fact that most dental schools are de-emphasizing the teaching of partial veneer restorations has created a situation whereby the 7/8 crown is rarely viewed as the treatment of choice. Time and experience will determine if the new ceramic materials, along with the all-important bonding agents, can achieve the success of a well-done, all-gold restoration.     

Analysis of internal defects in all-ceramic crowns using micro-focus X-ray computed tomography

The purpose of this study was to examine all-ceramic crowns for internal defects using micro-focus X-ray computed tomography (microCT). Mono-ceramic CAD/CAM crowns, ceramic-core CAD/CAM crowns, and heat-pressed ceramic crowns were used as specimens. The microCT images of the specimens were obtained and analyzed using a 3D volume rendering software. Mono-ceramic CAD/CAM crowns contained almost no pores, while ceramic-core CAD/CAM crowns contained pores only in the porcelain veneer area. Heat-pressed ceramic crowns had lots of pores in the cusps and the area around them. Results of this study indicated that internal pores in all-ceramic crowns could be observed non-destructively using microCT, and that CAD/CAM all-ceramic crowns contained fewer pores than crowns fabricated using manual techniques.     

All-ceramic primary telescopic crowns with Cerec inLab

On the one hand, all-ceramic primary telescopic dentures serve to satisfy the growing esthetic needs of older patients, and on the other hand guarantee good adhesive stability. With the aid of the Cerec inLab system, primary telescopic crowns made of Vita In-Ceram infiltration ceramic can be designed and milled after previous conventional determination of the over all insertion direction. The raw crowns gained in this way then require only minor improvement. The secondary parts are produced with the aid of electroforming. These are adhesively bonded to the tertiary structure. The special feature of adhesive bonding of the primary telescopic crowns requires uncompromisingly good cooperation between dentist and laboratory.     

Compressive strength of two modern all-ceramic crowns.

This study investigated the compressive strength of all-ceramic crowns manufactured using two recently introduced systems. The mean forces of fracture were 964 N for In-Ceram crowns, 814 N for paint-on IPS Empress crowns, and 750 N for layered IPS Empress crowns, compared with 1,494 N for metal ceramic crowns veneered on a nickel-chromium coping. The results indicate that clinical testing of these all-ceramic crowns is reasonable. Controlled, clinical, long-term evaluation is necessary to assess the safe application of these new crown systems.     

一步法同期设计制作玻璃纤维桩核和全瓷冠修复体的边缘微渗漏研究

目的 研究一步法同期设计制作纤维桩核和全瓷冠修复体的边缘微渗漏,为该方法的临床应用提供理论依据.方法 收集20颗离体牙,将其随机分为实验组和对照组,实验组同期进行桩道预备和全瓷冠基牙预备,数字化软件同期设计并切削制作玻璃纤维桩核+全瓷冠;对照组进行全瓷冠基牙预备,切削制作全瓷冠.所有样本进行温度循环试验和亚甲基蓝染色,...     

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目的寻找个性化全瓷修复体的制作方法及其相对于传统方法和标准CAD／CAM一体化制作的全瓷修复体的形态学优势。方法本实验于2012年11月至2013年1月在山西医科大学口腔医院以及山西联袂义齿加工中心完成（制作个性化全瓷冠）。选择标准树脂上下颌牙列模型,分别采用模拟标准左侧上颌第一磨牙形态进行CAD／CAM制作,CAD／CAM制作内冠后人工堆瓷外冠,以及标准化CAD／CAM3种方法制作左侧上颌第一磨牙全瓷冠,测试牙冠外形凸度以及牙尖斜面斜度并进行比较。结果个性化全瓷冠与标准左侧上颌第一磨牙相比其外形凸度及牙尖斜面斜度差异均无统计学意义（P〉0．05）,其他两种方法制作的全瓷冠与原始冠相比,外形凸度及牙尖斜面斜度差异均有统计学意义（P〈0．05）。结论采用模拟标准左侧上颌第一磨牙形态CAD／CAM制作的个性化全锆冠的全冠外形凸度和牙尖斜面斜度与标准左侧上颌第一磨牙更接近。     

Clinical complications in fixed prosthodontics

The purpose of this article is to identify the incidence of complications and the most common complications associated with single crowns, fixed partial dentures, all-ceramic crowns, resin-bonded prostheses, and posts and cores. A Medline and an extensive hand search were performed on English-language publications covering the last 50 years. The searches focused on publications that contained clinical data regarding success/failure/complications. Within each type of prosthesis, raw data were combined from multiple studies and mean values calculated to determine what trends were noted in the studies. The lowest incidence of clinical complications was associated with all-ceramic crowns (8%). Posts and cores (10%) and conventional single crowns (11%) had comparable clinical complications incidences. Resin-bonded prostheses (26%) and conventional fixed partial dentures (27%) were found to have comparable clinical complications incidences. The 3 most common complications encountered with all-ceramic crowns were crown fracture (7%), loss of retention (2%), and need for endodontic treatment (1%). The 3 most common complications associated with posts and cores were post loosening (5%), root fracture (3%), and caries (2%). With single crowns, the 3 most common complications were need for endodontic treatment (3%), porcelain veneer fracture (3%), and loss of retention (2%). When fixed partial denture studies were reviewed, the 3 most commonly reported complications were caries (18% of abutments), need for endodontic treatment (11% of abutments), and loss of retention (7% of prostheses). The 3 most common complications associated with resin-bonded prostheses were prosthesis debonding (21%), tooth discoloration (18%), and caries (7%).     

Cervical margin design with contemporary esthetic restorations

The contemporary dentist has a wide variety of options to use in the restoration of extensively damaged or previously restored teeth. Metal-ceramic and all-ceramic crowns are frequently used to restore esthetics and function. One of the essentials for success with either option is proper tooth preparation, which includes proper selection and preparation of the cervical margin of the preparation.     

冠修复材料导热性对基牙牙髓健康影响的研究

目的　研究金合金、金合金烤瓷、氧化锆全瓷等修复材料的导热性对牙髓健康的影响。方法　①实验室测量金合金、金合金烤瓷、氧化锆全瓷、自体牙、树脂粘接剂的导热系数;②随访金合金烤瓷冠、金合金铸造冠（颊侧烤瓷）和氧化锆全瓷冠修复的158颗活髓牙2年;对比158颗自体邻牙,统计出现牙髓炎、根尖周炎的牙数,并与几种材料的导热系数对照。结果　树脂粘接后,86%金合金导热系数37.89W/(m?K),21颗活髓基牙出现3例牙髓炎;86%金合金烤瓷导热系数0.85W/(m?K),58颗活髓基牙出现1例牙髓炎;氧化锆全瓷导热系数0.82W/(m?K),79颗活髓基牙无牙髓炎、根尖周炎发生;天然牙导热系数0.66W/(m?K),158颗活髓基牙无牙髓炎、根尖周炎发生;86%金合金铸造冠修复的基牙牙髓炎、根尖周炎阳性率远远高于其他几种低导热系数冠修复材料基牙（P＜0.01）。结论　冠修复材料的自身导热性能够影响基牙牙髓健康,如过高会对基牙牙髓健康不利。建议把导热系数最接近天然牙的氧化锆全瓷+树脂粘接剂组合作为冠修复材料的首选。