5 Written Questions
5 Matching Questions
- Which one is tougher?
- ___________represents the ability of a material to sustain a large permanent deformation under a <b>tensile</b> load before it fractures.
- Why do prostheses sometimes fail under a very small force, even though the strength of the prosthetic material is relatively high?
- When stress is induced in a two-unit cantilever bridge, where you would expect the tensile and compressive stress develop?
- b Resistance of a material to plastic deformation typically measured under an indentation load.
- c Flaws (could be microscopic)
- d b. dentin is tougher!
the more flexible material is the tougher it is. enamel is brittle
Tension would develop on the occlusal half where as compression would develop in the gingival half.
5 Multiple Choice Questions
- The relative amount of elastic energy per unit volume released on unloading of a test specimen.
- Ratio of force to the original cross-sectional area parallel to the direction of the force applied to a test specimen.
- 1. the stress intesntiy at these flaws increases with the length of the flaw, specially when it is oriented prependicular to the direction of tensile stress
2. flaws on the surface are associated with higher stresses than are flaws of the same size in interior regions.
maximum elastic stress (proportional limit)
5 True/False Questions
As the interatomic spacing increases, the internal energy increases. As long as the stress is <b>not greater than the proportional limit</b>, this <u>energy</u> is known as__________. → resilience
the term resilience is associated with 'springiness'
Elastic modulus → Relative stiffness of a material; ratio of elastic stress to elastic strain
Stress concentration →
Stress = Force / area
stress units - MPa
Name three properties that are related to heardness: → 1. tensile stress
2. shear stress
3. compressive stress
endurance limit → Relative ability of a material to deform physically under a <b>tensile</b> stress before it fractures