Irene M. Peterson

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The hypothesis under examination in this paper is that the lifetimes of dental restorations are limited by the accumulation of contact damage during oral function; and, moreover, that strengths of dental ceramics are significantly lower after multi-cycle loading than after single-cycle loading. Accordingly, indentation damage and associated strength(More)
Hertzian indentation testing is proposed as a protocol for evaluating the role of microstructure in the mechanical response of dental ceramics. A major advantage of Hertzian indentation over more traditional fracture-testing methodologies is that it emulates the loading conditions experienced by dental restorations: Clinical variables (masticatory force and(More)
Natural teeth (enamel/dentin) and most restorations are essentially layered structures. This study examines the hypothesis that coating thickness and coating/substrate mismatch are key factors in the determination of contact-induced damage in clinically relevant bilayer composites. Accordingly, we study crack patterns in two model "coating/substrate"(More)
OBJECTIVES This study examines the hypothesis that microstructure plays a critical role in the accumulation of strength-degrading damage in dental ceramics. A series of micaceous glass-ceramics crystallized from a common glass composition, using heat treatments to increase the diameter and aspect ratio of mica platelets, is used as a model ceramic system.(More)
All-ceramic crowns are coming into widespread use because of their superior esthetics and chemical inertness. This study examines the hypothesis that glass-infiltrated alumina and spinel core ceramics are resistant to damage accumulation and strength degradation under representative oral contact conditions. Accordingly, Hertzian indentation testing with(More)
Laminate structures consisting of hard, brittle coatings and soft, tough substrates are important in a wide variety of engineering applications (cutting tools, electronic multilayers, laminated windscreens), biological structures (teeth and dental crowns, shells, bones), and traditional pottery (ceramic glazes). A hard outerlayer variously offers increased(More)
A model of contact damage accumulation from cyclic loading with spheres and ensuing strength degradation in relatively tough, heterogeneous ceramics is developed. The damage takes the form of a quasi-plastic zone beneath the contact, consisting of an array of closed frictional shear faults with attendant “wing” microcracks at their ends. Contact fatigue(More)
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