Fundamentals of Dental Material Science Flashcards
describe amalgams use in restorations
applied cyclically with low level forces, and it can protrude around the margins and become vulnerable to fracture
exposed amalgam is fractured
what is used to bond the composite to the enamel
acid etch that is 30% phosphoric acid
describe glass ionomer cement
this is another restorative material that binds to enamel.
the fluoride is released at 1ppm per day to increase enamels resistance to the development of dental caries
why is thermal expansion important
the restorative material needs to be able to expand and contract as the teeth do otherwise microleakage can occur
why are low viscosity impression materials good
they have an accurate record of the tooth surface detail
why are high viscosity impression materials useful
they are the most dimensionally stable after setting and removing
what are metal alloys used for
partial denture frameworks
orthodontic wires
denture bases
what is elasticity
the ability of a material to return to its original shape on removal from the mouth using an applied force
what is rigidity
a measure of how much force is needed to cause a temporary change in shape of material
what is compressive strength
abilit to withstand applied commpressive forces without fracturing
what is hardness
the ability of the surface to withstand idendentation resistance to abrasion ie removal of the surface layer
what is creep
change in shape due to repetitive application of small forces
