Ceramics have many compelling properties that render them attractive candidates for dental restorations: these properties including hardness, chemical durability, wear resistance, and, in specific cases, machinability. The objective of this project in the broader Machinable Ceramics Program is to investigate the fracture and fatigue characteristics of dental ceramics, with an emphasis on machinable ceramics. We propose a systematic contact fatigue study using a novel and simple, yet powerful, Hertzian indentation methodology developed at NIST. Our emphasis will be on interrelations between damage accumulation in cyclic loading and key elements of material microstructure. A key element in the study will be the relationship between damage patterns with observations from clinical failures.
Specific aims i nclude: (1) carry out repeat-load indentation experiments on chosen machinable ceramics, to evaluate fatigue properties; (2) a systematic analysis of the damage mechanisms in these ceramics, using optical and electron microscopy and acoustic emission; (3) theoretically analyze the damage accumulation patterns, using fracture mechanics; (4) measure the strength of specimens as a function of number of indentation cycles, to assess lifetime characteristics; (5) conduct comparative tests in various environments, inert (dry nitrogen), air and water, to evaluate the effect of chemical enhancement in the damage process; (6) conduct comparative tests on machined and surface-modified surfaces, to investigate potential enhancement or inhibition of fatigue degradation from persistent surface stresses and flaw state; (7) correlate damage patterns on the laboratory specimens with those on clinical restorations (8) relate the observed properties to microstructural variables, so that materials processing strategies for the next generation of dental materials may be laid down. The techniques that we propose to use here to analyze the fatigue and fracture properties, based as they are on the most recent developments in fracture mechanics at the microstructural level, are at the forefront of current ceramics science. They offer a sound basis for the future materials evaluation and design for specific dental (and potentially other biomedical) applications. They also promise new insights into the machinability and wear resistance characteristics that form the focus of other phases of the broader program.
| Yin, Ling (2012) Property-process relations in simulated clinical abrasive adjusting of dental ceramics. J Mech Behav Biomed Mater 16:55-65 |
| Silva, N R F A; Bonfante, E A; Rafferty, B T et al. (2011) Modified Y-TZP core design improves all-ceramic crown reliability. J Dent Res 90:104-8 |
| Rafferty, Brian T; Janal, Malvin N; Zavanelli, Ricardo A et al. (2010) Design features of a three-dimensional molar crown and related maximum principal stress. A finite element model study. Dent Mater 26:156-63 |
| Bonfante, Estevam A; Sailer, Irena; Silva, Nelson R F A et al. (2010) Failure modes of Y-TZP crowns at different cusp inclines. J Dent 38:707-12 |
| Guess, P C; Zhang, Y; Kim, J-W et al. (2010) Damage and reliability of Y-TZP after cementation surface treatment. J Dent Res 89:592-6 |
| Coelho, P G; Silva, N R; Bonfante, E A et al. (2009) Fatigue testing of two porcelain-zirconia all-ceramic crown systems. Dent Mater 25:1122-7 |
| Rekow, E Dianne; Zhang, Guangming; Thompson, Van et al. (2009) Effects of geometry on fracture initiation and propagation in all-ceramic crowns. J Biomed Mater Res B Appl Biomater 88:436-46 |
| Coelho, Paulo G; Silva, Nelson R; Thompson, Van P et al. (2009) Effect of proximal wall height on all-ceramic crown core stress distribution: a finite element analysis study. Int J Prosthodont 22:78-86 |
| Zhang, Yu; Kim, Jae-Won; Bhowmick, Sanjit et al. (2009) Competition of fracture mechanisms in monolithic dental ceramics: flat model systems. J Biomed Mater Res B Appl Biomater 88:402-11 |
| Guess, Petra C; Zhang, Yu; Thompson, Van P (2009) Effect of veneering techniques on damage and reliability of Y-TZP trilayers. Eur J Esthet Dent 4:262-76 |
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