J. Appl. Cryst.の発刊に際して

Statement of problem Developments in ceramic core materials such as lithium disilicate, aluminum oxide, and zirconium oxide have allowed more widespread application of all-ceramic restorations over the past 10 years. With a plethora of ceramic materials and systems currently available for use, an overview of the scientific literature on the efficacy of this treatment therapy is indicated. Purpose This article reviews the current literature covering all-ceramic materials and systems, with respect to survival, material properties, marginal and internal fit, cementation and bonding, and color and esthetics, and provides clinical recommendations for their use. Material and methods A comprehensive review of the literature was completed seeking evidence for the treatment of teeth with all-ceramic restorations. A search of English language peer-reviewed literature was undertaken using MEDLINE and PubMed with a focus on evidence-based research articles published between 1996 and 2006. A hand search of relevant dental journals was also completed. Randomized controlled trials, nonrandomized controlled studies, longitudinal experimental clinical studies, longitudinal prospective studies, and longitudinal retrospective studies were reviewed. The last search was conducted on June 12, 2007. Data supporting the clinical application of all-ceramic materials and systems was sought. Results The literature demonstrates that multiple all-ceramic materials and systems are currently available for clinical use, and there is not a single universal material or system for all clinical situations. The successful application is dependent upon the clinician to match the materials, manufacturing techniques, and cementation or bonding procedures, with the individual clinical situation. Conclusions Within the scope of this systematic review, there is no evidence to support the universal application of a single ceramic material and system for all clinical situations. Additional longitudinal clinical studies are required to advance the development of ceramic materials and systems.

Current ceramic materials and systems with clinical recommendations: A systematic review

In this article, we review the recent history of the development of dental CAD/CAM systems for the fabrication of crowns and fixed partial dentures (FPDs), based on our 20 years of experience in this field. The current status of commercial dental CAD/CAM systems developed around the world is evaluated, with particular focus on the field of ceramic crowns and FPDs. Finally, we discuss the future perspectives applicable to dental CAD/CAM. The use of dental CAD/CAM systems is promising not only in the field of crowns and FPDs but also in other fields of dentistry, even if the contribution is presently limited. CAD/CAM technology will contribute to patients' health and QOL in the aging society.

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A review of dental CAD/CAM: current status and future perspectives from 20 years of experience.

Purpose The aim of this prospective clinical cohort study was to determine the success rate of 3- to 5-unit zirconia frameworks for posterior fixed partial dentures (FPDs) after 5 years of clinical observation. Materials and methods Forty-five patients who needed at least 1 FPD to replace 1 to 3 posterior teeth were included in the study. Fifty-seven 3- to 5-unit FPDs with zirconia frameworks were cemented with 1 of 2 resin cements (Variolink or Panavia TC). The following parameters were evaluated at baseline, after 6 months, and 1 to 5 years after cementation at test (abutments) and control (contralateral) teeth: probing pocket depth, probing attachment level, Plaque Index, bleeding on probing, and tooth vitality. Intraoral radiographs of the FPDs were taken. Statistical analysis was performed using descriptive statistics, Kaplan-Meier survival analysis, and the McNemar test. Results Twenty-seven patients with 33 zirconia FPDs were examined after a mean observation period of 53.4 +/- 13 months. Eleven patients with 17 FPDs were lost to follow-up. After the 3-year recall visit, 7 FPDs in 7 patients were replaced because they were not clinically acceptable due to biologic or technical complications. After 5 years of clinical observation, 12 FPDs in 12 patients had to be replaced. One 5-unit FPD fractured as a result of trauma after 38 months. The success rate of the zirconia frameworks was 97.8%; however, the survival rate was 73.9% due to other complications. Secondary caries was found in 21.7% of the FPDs, and chipping of the veneering ceramic in 15.2%. There were no significant differences between the periodontal parameters of the test and control teeth. Conclusions Zirconia offers sufficient stability as a framework material for 3- and 4-unit posterior FPDs. The fit of the frameworks and veneering ceramics, however, should be improved.

Five-year clinical results of zirconia frameworks for posterior fixed partial dentures.

Objectives: The objective of this systematic review was to assess the 5-year survival rates and incidences of complications of all-ceramic fixed dental prostheses (FDPs) and to compare them with those of metal‐ceramic FDPs. Methods: An electronic MEDLINE and Dental Global Publication Research System search complemented by manual searching was conducted to identify prospective and retrospective cohort studies on all-ceramic and metal‐ceramic reconstructions with a mean follow-up time of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data abstraction was performed independently by three reviewers. Failure rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of 5-year survival proportions. Results: The search provided 3473 titles for single crowns and FDPs and resulted in 100

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A systematic review of the survival and complication rates of all‐ceramic and metal–ceramic reconstructions after an observation period of at least 3 years. Part II: fixed dental prostheses.

All-ceramic dental bridges for the molar region are not yet available at reasonable costs. The novel direct ceramic machining (DCM) process allows an easy, reliable and rapid fabrication for all-ceramic dental restorations with high mechanical strength and good biocompatibility. In DCM, an enlarged framework is easily milled out of a pre-fabricated porous ceramic blank made of zirconia. After sintering to full density, no further time-consuming hard machining with diamond tools is needed. For individual esthetical requirements, the framework is coated with a veneer porcelain. Compared to the commercially available In-Ceram Alumina and IPS Empress2 restorations, the mechanical strength of zirconia frameworks is twice as high, allowing the restorations to bear the high mastication forces in the molar region. In terms of reliability, zirconia bridges fabricated by the DCM process are also superior to In-Ceram Alumina and IPS Empress2. A clinical study of three-unit dental bridges in the molar region found no problems after the first year of observation.

Reliability and strength of all-ceramic dental restorations fabricated by direct ceramic machining (DCM).

In vitro lifetime of dental ceramics under cyclic loading in water.

Cyclic fatigue in water of veneer–framework composites for all-ceramic dental bridges

The microstructure of coagulated colloidal particles, for which the interparticle potential is described by the Derjaguin-Landau-Verweg-Overbeek theory, is strongly influenced by the particles' surface potential. Depending on its value, the resulting microstructures are either more "homogeneous" or more "heterogeneous," at equal volume fractions. An adequate quantification of a structure's degree of heterogeneity (DOH), however, does not yet exist. In this work, methods to quantify and thus classify the DOH of microstructures are investigated and compared. Three methods are evaluated using particle packings generated by Brownian dynamics simulations: (1) the pore size distribution, (2) the density-fluctuation method, and (3) the Voronoi volume distribution. Each method provides a scalar measure, either via a parameter in a fit function or an integral, which correlates with the heterogeneity of the microstructure and which thus allows to quantitatively capture the DOH of a granular material. An analysis of the differences in the density fluctuations between two structures additionally allows for a detailed determination of the length scale on which differences in heterogeneity are most pronounced.

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Quantification of the heterogeneity of particle packings.

The macroscopic mechanical properties of wet ceramic green bodies and densely packed coagulated colloidal particle gels strongly depend on the local arrangement of the powder particles on length scales of a few particle diameters Heterogeneous microstructures exhibit up to one order of magnitude higher elastic properties and yield strengths than their homogeneous counterparts The microstructures of these gels are analysed by the “straight path” method quantifying quasi-linear arrangements of particles They show similar characteristics than force chains bearing the mechanical load in granular material Applying this concept to gels revealed that heterogeneous colloidal microstructures show a significantly higher straight path density and exhibit longer straight paths than their homogeneous counterparts

https://people.physics.anu.edu.au/~tas110/Teaching/Lectures/L17/Material/Schenkler_ETH_JECS_08.pdf

Frank T. Filser

Papers

Reliability and strength of all-ceramic dental restorations fabricated by direct ceramic machining (DCM).

In vitro lifetime of dental ceramics under cyclic loading in water.

Cyclic fatigue in water of veneer–framework composites for all-ceramic dental bridges

Quantification of the heterogeneity of particle packings.

Microstructures and mechanical properties of dense particle gels: Microstructural characterisation