Fundamentals of Dental Materials Science Flashcards
what are the constantly used dental material?
amalgam, impression materials, acrylic resin, composite resin, gypsum, alloys
what are the different material types?
restorative, impression, dentures, metals and alloys
what influences cavity design?
material chosen
what is needed for composite resin to bind to the tooth?
acid etch technique
what does resin-modified glass isomer cement bind to?
enamel
what does resin-modified glass isomer cement do?
releases fluoride and increases enamel resistance to developing caries
what happens if restorative material does no contract/expand as the tooth does?
microleakage occurs
what does viscosity mean?
ability to flow
what is a low viscosity impression material good for?
most accurate record of tooth surface detail
what is a high viscosity impression material good for?
most dimensionally stable after setting and removing
how are impressions taken using a high viscosity material?
material placed in tray e.g. polyether, addition silicon and tray is inserted for patient to bite into
how are impressions taken using a low viscosity material?
low viscosity material placed around individual teeth and then the initial impression tray is inserted
what does it mean if a material is elastic?
full recovery of shape
what does it mean if a material is non-elastic?
permanent deformation
what is gypsum?
dental stone
what is a negative replica?
the impression in the tray
what is a positive replica?
the dental stone cast
what is transverse strength - 3 point loading?
how well does an acrylic upper denture cope with forces that cause deflection
what are the uses of metal alloys?
partial denture frameworks, orthodontic wires, denture bases
what does it mean if something is rigid?
there is little change in shape when large stress is applied
what are the properties of dental materials?
mechanical, thermal, flow, miscellaneous
what are the mechanical properties of dental material?
strength, rigidity, hardness, abrasion resistance
what are the thermal properties of dental materials?
expansion coefficient, conduction
what are the flow properties of dental materials?
viscosity, visco-elasticity
what are the miscellaneous properties of dental materials?
creep
what does viscosity mean?
the ability to flow
what does elasticity mean?
ability of material to return to its original shape on removal from mouth using an applied force
what is rigidity?
measure of how much force is needed to cause a temporary change in shape of material
what is compressive strength?
ability to withstand applied compressive force without fracturing
what is hardness?
ability to withstand indentation and the resistance to abrasion
what is creep?
change in shape due to repetitive application of small forces
