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55 Cards in this Set
- Front
- Back
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Biocompatible
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the property of a material that allows it to not impede or adversely affect living tissue |
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Therapeutic agents |
materials used to treat disease |
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Restorative agents |
materials used to reconstruct tooth structure |
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compressive force |
force applied to compress an object - posterior teeth ideally suited - large occlusal surface and multi rooted base will resist crushing foce |
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Tensile force |
force applied in opposite directions to stretch an object - when biting forces are used to stretch a material. the tooth is exterting tensile force |
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shearing force |
force applied when two surfaces slide against each other or in a twisting or rotating motion - incisor used for cutting |
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stress |
the internal force, which resists the applied force |
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strain |
distortion or deformation that occurs when an object cannot resist a stress |
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flexural stress |
bending caused by a combination of tension and compression |
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solubility |
susceptible to being dissolved |
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corrosion |
deterioration of a metal caused by a chemical attack or electrochemical reaction with dissimilar metals in the prescence of a solution containing electrolytes |
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tarnish |
discoloration resulting from oxidation of a thin latter of a metal at is surface. it is not as destructive as corrosion |
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water sorption |
the ability to absorb moisture |
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galvanism |
an electrical current transmitted between two dissimilar metals |
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dimensional change |
a change in the size of matter. for dental materials, this usually manifests as expansion caused by heating and contraction caused by cooling |
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coefficient of thermal expansion |
the measurement of change of volume or length in relationship to change in temperature |
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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 ingestion of cold or hot fluids or foods |
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thermal conductivity
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the rate at which heat flows through a material |
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insulators |
materials having low thermal conductivity |
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exothermic reaction |
the production of heat resulting from the reaction of the components of some materials when they are mixed |
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adhesion |
the act of sticking two things together. in dentistry it is used to describe the bonding or the 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 |
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Bonding |
to connect or fasten; to bind |
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Wetting |
the ability of a liquid to wet or intimately contact a solid surface - water beading on a waxed car is an example of poor wetting |
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Viscosity |
the ability of a liquid material to flow |
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Film thickness |
the minimum thickness obtainable by a layer of a material. it is particularly important to dental cements |
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surface energy
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the electrical charge that attracts atoms to a surface |
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Interface |
the space between the walls of the preparation and the restoration |
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microleakage |
leakage of fluid and bacteria caused by microscopic gaps that occur at the interface of the tooth and the restoration margins |
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hue |
the color of the tooth or restoration. it may include a mixture of colors such as yellow brown |
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chroma |
the intensity or strength of a color |
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value |
how light or dark a color is. a low value is darker and a high value is brighter |
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transparent |
light passing directly through an object |
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opaque |
optical property in which light is completely absorbed by an object |
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fatigue failure |
a fracture resulting from repeated stresses that produce microscopic flaws that grow |
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retention |
a materials ability to maintain its position without displacement under stress |
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translucency |
varying degrees of light passing through and being absorbed by an object |
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vitality |
a life like quality |
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conditions for assessing restorations |
- dry field - good lighting - sharp explorer - radiographs - magnification - good knowledge of the material |
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the safe interaction of dental materials with the rest of the body is |
biocompatibility |
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the study of dental materials consists of |
- chemical reaction to the material - physical reaction to the material - manipulation of the material |
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the internal reaction to an externally applied force is called |
stress |
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what restorative material is most likely to fracture under compressive force |
porcelain |
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which restorative material is the least soluble |
porcelain |
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corrosion os of greatest concern for what restorative material |
amalgam |
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surface discoloration of a metal restoration is called |
tarnish |
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restorative materials with values of thermal conductivity similar to enamel include |
composite resin |
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an example of galvanism is |
amalgam contacting gold |
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micro leakage may be responsible for |
- recurrent decay - marginal staining - postoperative sensitivity |
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an excessive film thickness may cause |
improper setting of the restoration |
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the leakage of fluids and debris extending along the tooth restoration interface is called |
microleakage |
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materials used for the restoration of enamel need hight |
vitality |
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color shades can vary depending on the incident light or source of light. this is called |
metamerism |
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why study dental materials |
- safety handling, disposal, patient safety - maintenance- cleaning, polishing, instrumentation - delivery behavior of material, manipulation of material, assisting in the delivery of material - patient education options of material choices, maintenance |
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Density |
the measure of the weight of a material compared with its volume |
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Brittleness |
hard and likely to break or crack |
