Dental Materials Science Flashcards
What are examples of potential restorative materials?
- amalgam
- composite resin
What are ditched margins?
- fractured amalgam causes these
- causes an ingress of fluids and bacteria
- can cause secondary caries
What is the acid etch technique?
30% phosphoric acid applied to enamel surface for 20 seconds to roughen it for composite to adhere
Describe composite resin application
- unfilled resin applied to etched enamel
- composite resin bonds to unfilled resin
Describe renin-modified glass ionomer cement?
- bonds to enamel
- 1ppm fluoride released per day
What can cause micro leakage?
If the restorative material doesn’t expand and contract as the tooth does
Describe the importance of impression material viscosity
Viscosity- ability to flow
- a lower viscosity gives a more accurate record of tooth surface detail, placed around individual teeth before lower viscosity material follows- two-tone impression
- however the material must be thick enough to be stable after setting and removing
Describe elasticity of impression material
The material must be elastic enough to strain and move during removal but recoil and recover after
What is an example of a negative replica?
An impression
What is an example of a positive replica?
Dental stone
What are examples of metal and alloy materials?
- partial dental frameworks
- orthodontic wires
- denture bases
Why are alloys used despite being unattractive?
Strength = long lasting
What is protruded amalgam?
Force applied to the amalgam changes its shape and can produce protruded amalgam material at the margins making it vulnerable to fracture
Which restorative material has best compression strength?
Amalgam has better compression strength than composite resin
What is a two tone impression?
- original high viscosity impression taken
- second low viscosity impression material placed around individual teeth
- initial impression tray reinserted
