5 Written questions
5 Matching questions
- Tensile strength for:
a. Dental porcelain
c. Resin-based composite
e. Alumnia ceramic
- Compressive stress
- For brittle materials that exhibit only elastic deformation and can sustain no plastic deformation, stresses at or slightly above the ________________ result in fracture.
- Elastic modulus
- Toughness increases with increases in _____ and _________.
- a a. Dental porcelain → 50-100 MPa
b. Amalgam → 27-55 MPa
c. Resin-based composite → 30-90 MPa
d. Poly → 60 MPa
e. Alumnia ceramic → 120 MPa
- b Relative stiffness of a material; ratio of elastic stress to elastic strain
- c Ratio of compressive force to cross-sectional area prependicular to the axis of applied force.
maximum elastic stress (proportional limit)
- e Toughness increases with increases in strength and ductility.
5 Multiple choice questions
dentin → 50 MPa
enamel → 10 MPa
- Compressive <b>stress</b> within a compression test specimen at the point of fracture.
note: compressive stress -Ratio of compressive force to cross-sectional area perpendicular to the axis of applied force.
- Giganewtons per square meter (GN/m²), or gigapascals (<b>GPa</b>)
5 True/False questions
the stress above which stress is no longer proportional to strain. → Proportional limit
True stress → Ratio of applied force to the actual cross-sectional area; however, for convenience stress is often calculated as the ratio of applied force to the initial cross-sectional area.
Maximum stress that is required to cause fracture is called _________. → Ultimate strength
Why do prostheses sometimes fail under a very small force, even though the strength of the prosthetic material is relatively high? → Flaws (could be microscopic)
Maximum stress that a structure can withstand without sustaining a specific amount of plastic strain (yield strength) or stress at the point of fracture (ultimate strength).