Resistance to Fracture of Three All-Ceramic Systems

Abstract: All-ceramic restorations have become an attractive alternative to porcelain-fused-to-metal crowns, but their strength is still an important issue. The purpose of this study was to compare the in vitro fracture resistance of three all-ceramic systems: IPS Empress, In-Ceram, and Procera AllCeram. Thirty dies were replicated from a master die using high filler resin with a modulus of elasticity similar to dentin. Ten cores each of In-Ceram and Procera were fabricated to a thickness of 0.5 mm. The remaining porcelain was applied using a sculpting device to produce a crown with a final thickness of 1.0 mm axially and 2.5 mm occlusally. Ten IPS Empress crowns were waxed to the same dimensions and were pressed by the manufacturer. The internal surfaces of all the crowns were etched and silanated prior to cementation with a resin cement (Panavia 21). The cemented samples were loaded in an Instron machine until fracture. The mean fracture loads were: IPS Empress, 222.45 (±49) kg; In-Ceram, 218.8 (±36) kg; Procera AllCeram, 194.20 (±37) kg. Tukey's test showed no statistically significant differences among the three all-ceramic systems at p < .05.     

In Vitro Evaluation and Comparison of the Translucency of Two Different All-Ceramic Systems

Objectives

The aim of this study was to evaluate and compare the translucency of two different all-ceramic systems using Vita Easyshade digital shade matching device in an in vitro model.

Materials and methods

Translucency of lithium disilicate glass-ceramic (IPS e.max Press) and zirconia all-ceramic system (Ceramill ZI) were evaluated and compared. A total of 5 square-shaped specimens with 0.5 mm thickness were fabricated from each ceramic system in A1 shade according to Vitapan Classical shade tab. Specimens were then veneered and glazed with corresponding veneer ceramics recommended by each system manufacturer and the total thickness was set to 1.5 mm. Translucency was evaluated using VITA Easyshade in two stages: before and after veneering and glazing on black and white background. Translucency parameter (TP) was calculated. A one-way ANOVA and Bonferonni tests were used when appropriate (α=0.05).

Results

Lithium disilicate glass-ceramic was significantly more translucent than the zirconia system in both stages (P<0.05). Translucency of all specimens was significantly decreased after veneering and glazing in both all-ceramic systems (P<0.05).

Conclusion

The translucency of two different dental ceramics was significantly influenced by both material and stages of preparation. Within the limitations of the experiment, these results can be valuable and help the clinician to make appropriate esthetic decisions.Key words: tooth color, dental shade-matching device, translucency, glass-ceramics, zirconia     

A Clinical Report and Overview of Scientific Studies and Clinical Procedures Conducted on the 3M ESPE Lava™ All-Ceramic System

The Lava All-Ceramic System (3M ESPE Dental Products, St. Paul, MN) is a high-strength zirconia system, which can be utilized to create all-ceramic crowns and fixed partial dentures (FPDs) for use in the anterior and posterior regions of the oral cavity. The following study offers an overview of previously conducted scientific studies and clinical procedures that feature the Lava All-Ceramic System as well as a more general overview of zirconia ceramics. A clinical report demonstrates the use of the Lava All-Ceramic System with the restoration of 2 single crowns.     

Cercon全瓷在口腔固定修复中的应用初探

目的对Cereon全瓷的制作I艺及临床效果进行评估。方法对5例患者共15牙单位的冠、桥使用Cer- con全瓷系统进行修复,并进行修复后1,3,6,12月的临床追踪观察。结果Ce~全瓷修复体美观自然,无折断、开裂、崩瓷、变色,牙酿组织无红肿、压痛。结论Ce~全瓷系统是目前较理想的口腔固定修复材料。     

The Correlation of Crack Lines and Definitive Restorations with the Survival and Success Rates of Cracked Teeth: A Long-term Retrospective Clinical Study

IntroductionCracked teeth frequently require protective adhesive restorations. This long-term, longitudinal retrospective clinical study aimed to evaluate the factors influencing the success and survival rates of cracked teeth with crack lines (CLs) in different directions when restored early with onlays or full-coverage crowns.MethodsThe dental records of 71 patients with a total of 86 cracked teeth with different pulpal and periapical diagnoses and with follow-ups spanning over 1–11 years were included. Data regarding the demographics; clinical symptoms and signs; bruxism; occlusal interferences; eating habits; pulpal and periapical diagnoses; number, direction, location, and extent of CLs; probing depth; and coronary condition before and after the placement of definitive restorations were collected. Univariate associations between tooth survival and explanatory variables were assessed. The long-term survival rate was estimated using Kaplan-Meier analysis and the log-rank test. A multivariate analysis was performed using Cox regression analysis.ResultsThe overall success rate was 93.0%, and the overall survival estimates of cracked teeth restored early were 98.6%, 94.9%, and 55.9% at the 1-, 5-, and 11-year follow-ups, respectively. The direction of the CLs did not influence the survival of the tooth. No significant association was observed between the type of tooth, probing depth, root canal treatment, and tooth loss (P > .05). The multivariate analysis showed that previously treated cracked teeth (P < .05), the provision of onlay restorations (P < .05), and the placement of posts (P < .05) had higher correlations with tooth loss. Additionally, the placement of full-coverage crowns resulted in lower tooth loss compared with the placement of onlays (P < .05).ConclusionsPrevious endodontic treatment in teeth that subsequently develop CLs has a negative impact on the survival rate of the teeth. Moreover, early placement of full-coverage crowns should be implemented for cracked teeth regardless of the direction or the number of CLs because it is associated with a higher cracked tooth survival rate.     

Anterior Provisional Restorations Used to Determine Form, Function, and Esthetics for Complex Restorative Situations, Using All-Ceramic Restorative Systems

A technique is proposed for the restoration of a large and visible maxillary anterior defect. The importance of proper diagnosis, treatment planning, and communication is emphasized. Irreversible treatment should only be rendered once patient approval has been obtained through objective evaluation with provisional restorations. The techniques presented in this article use a combination of ceramic systems currently available to satisfy functional demands while achieving acceptable esthetics. A controlled series of steps, where the provisional restorative components are being replaced by the definitive ones is planned. The only difference between the provisional and definitive restorative components is the material used. The definitive restorations consisted of an implant-supported zirconium oxide framework. Individual pressed porcelain restorations were luted to the framework and a natural tooth.

CLINICAL SIGNIFICANCE

Provisional restorations allow an objective form of communication. Vertical and horizontal transitional lines can be effectively masked with appropriate treatment planning and a skilled ceramist. Many traditional dental laboratory steps may be eliminated or simplified without compromising the definitive restorations.
( J Esthet Restor Dent 22:7–17, 2010)     

Survival Rates of Teeth with Primary Endodontic Treatment after Core/Post and Crown Placement

Introduction

The objective of this study was to determine the effect of delayed placement of the core/post and crown on the outcomes of nonsurgical root canal therapy (NSRCT).

成功运用氧化锆种植体及全瓷冠进行上颌中切牙美容修复的病例报告

陶瓷工艺应用于口腔医学和临床医学已有多年历史,现今氧化锆因其出色的机械性能成为最受欢迎的陶瓷材料之一．并已应用于以前仅能采用金属材料修复的病例中。氧化锆作为单冠及长桥的基底材料已应用多年．同时也被作为植入体用于髋关节置换以及指、趾、腕关节。近期有部分研究报道使用氧化锆种植体修复缺失牙。本文展示了1例使用表面粗化的氧化锆种植体进行美学修复的病例。一名28岁的男性患者要求修复缺失的上中切牙。两颗表面粗化的（CeraRoot）氧化锆种植体被用于上中切牙拔牙后的即刻修复．术后戴入即刻临时冠．三个月后最终全瓷修复体粘结完成。氧化锆种植体可作为种植修复材料很好的选择．尤其适用于美观要求较高的病例．但仍需要更多的相关研究用于评价不同表面结构的氧化锆种植体的远期临床效果。     

Comparison of the Load at Fracture of Turkom-Cera to Procera AllCeram and In-Ceram All-Ceramic Restorations

Purpose: This study investigated the occlusal fracture resistance of Turkom-Cera-fused alumina compared to Procera AllCeram and In-Ceram all-ceramic restorations.
Materials and Methods: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Ten copings of 0.6 mm thickness were fabricated from each type of ceramic, for a total of thirty copings. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented with resin luting cement Panavia F according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37°C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.
Results: The results of the present study showed the following mean loads at fracture: Turkom-Cera (2184 ± 164 N), In-Ceram (2042 ± 200 N), and Procera AllCeram (1954 ± 211 N). ANOVA and Scheffe's post hoc test showed that the mean load at fracture of Turkom-Cera was significantly different from Procera AllCeram ( p < 0.05). Scheffe's post hoc test showed no significant difference between the mean load at fracture of Turkom-Cera and In-Ceram or between the mean load at fracture of In-Ceram and Procera AllCeram.
Conclusion: Because Turkom-Cera demonstrated equal to or higher loads at fracture than currently accepted all-ceramic materials, it would seem to be acceptable for fabrication of anterior and posterior ceramic crowns.     

Fabrication of a Surgical Guide with Help of a Milling Machine by Ridge Mapping Method

Optimizing the prosthetic result by customization of a surgical guide should be a major consideration in the implant placement. The design of the surgical guide must account for several factors, including position of the implant, the tissue present, and the anticipated prosthesis. The objective of this article is to present a technique for fabrication and customization of surgical guide with the help of ridge mapping procedure and a milling machine. This technique is helpful for the beginners in implant dentistry and for the dentists who cannot avail the CBCT/medical CT facilities.     

辨证论治口腔扁平苔藓260例疗效观察

目的:探讨采用中医辨证法治疗口腔扁平苔藓的疗效。方法:将260例口腔扁平苔藓患者随机分为治疗组和对照组,每组各130例。治疗组辨证分型为气滞血瘀型、肝肾阴虚型、血虚风燥型、肝气郁结型、脾胃湿热型,分别组方用药。对照组采用口服硫酸羟氯喹及局部治疗。结果:治疗组总有效率为91.5%,各辨证型有效率分别为100%、94.4%、92.3%、91.3%、71.4%。治疗组各辨证分型中气虚血瘀型患者占多数,疗效最好;睥虚湿热型有效率相对最低。对照组总有效率为66.2%。结论:提示中草药治疗口腔扁平苔藓的作用是肯定的,有良好的应用前景,值得在临床上推广。