Chapter 2 Flashcards
What is flexural stress?
Bending caused by a combination of tension and compression.
Fatigue Failure
A fracture resulting from repeated stresses that produce microscopic flaws that grow.
Retention
A material’s ability to maintains its position without displacement under stress.
Solubility
Susceptible to being dissolved
Water sorption
The ability to absorb moisture
Corrosion
Deterioration of a metal caused by a chemical attack or electrochemical reaction with dissimilar metals in the presence of a solution containing electrolytes (such as saliva)
Tarnish
Discoloration resulting from oxidation of a thin layer of metal at its surface. It is not as destructive as corrosion.
Galvanism
An electrical current transmitted between two dissimilar metals.
Dimensional Change
A change in the size of matter. In regards to dental materials this usually manifest in expansion (heat) and 9cooling) contraction.
Coefficient of Thermal Expansion
The measurement of change of volume or length in relationship to change in temperature.
Percolation
Movement of fluid in the microscopic gap of the restoration margin as a result of differences in the expansion and contraction rates of the tooth and the restoration with temperature changes associated with the ingestion of cold or hot fluids or foods.
Thermal conductivity
The rate at which heat flows through a material.
Insulators
Materials having low thermal conductivity
Exothermic Reaction
The production of heat resulting from the reaction of the components of some materials when they are mixed.
Adhesion
The act of sticking two things together. In dentistry, it is used to describe the bonding or cementation process. Chemical adhesion occurs when atoms or molecules of dissimilar substances bond together and differs from cohesion in which attraction among atoms and molecules of like materials holds them together.
Bonding
To connect or fasten
Wetting
The ability of a liquid to wet or intimately contact a solid surface.
Viscosity
The ability of a liquid material to flow.
Film Thickness
The minimum thickness obtainable by a layer of material. It is particularly important to dental cements.
Surface Energy
The electrical charge that attracts atoms to a surface.
Interface
The space between the walls of a preparation and the restoration.
Microleakage
Leakage of fluid and bacteria caused by microscopic gaps that occur at the interface of the tooth and the restoration margin.
Hue
The color of the tooth or restoration (posts. Mixture of colors)
Chroma
The intensity or strength of a color.
Value
How light or dark a color is (lower value is darker High value is brighter)
Transparent
Light passing directly through an object
Opaque
Optical property in which light is completely absorbed by an object.
Transclucency
Varying degrees of light passing through and being absorbed by an object.
Vitality
A lifelike quality
