Flashcards in dental materials Deck (34):
what is the medical devices directive changes?
-statement of manufacture offered to all patients recieving dental appliance
-GDC often invite patients to ask for this certificate
what is an alloy?
-a mixture of two or more metals
what is a grain boundary?
-where the crystals meet
-a source of tension
how are grain boundaries visualised?
-light reflecting microscope
what are the 3 different types of solid solution?
1. ordered solid solution
2. random solid solution
3. interstitual solid solution
what are the two compositions of amalgam?
2.copper enriched ( high copper)
what is to composition of conventional amalgam?
65% Ag, 29% Sn, 6% Cu, 2% Zn, 3% Hg
what is the composition of high copper amalgam?
40% Ag, 32% Sn, 30% Cu, 2% Zn, 3% Hg
what is the ISO limits of expansion/contraction??
what does Zn act as in amalgam?
-Zn acts as a scavenger for Oxygen
when is amalgam fully set?
24hrs after placement
what is creep?
-protrusions at restoration margins
-gamma 2 phase is largerly, not exclusively responsible
what does corrosion provide?
-corrosion provides marginal seal
Mercury compounds in amalgam are known to be toxic to what?
what are silicates?
-earliest tooth coloured restorative material
-prone to eriosion
what are the 4 stages of free radical polymerisation of methyl methacrolate?
what is a resin composite?
-a combination of two chemically different materials with a distinct interface seperating the components and having properties which could not be achieved by any of the components alone
what are the 3 kinds of resin composites?
for a product to be on the market, what must they confirm with?
what is an ormocer?
-monomer free nano-hybrid composite
can you place an amalgam in a pt that is pregnant?
-No. Department of health banned amalgam placing in pts that are pregnant
what are the two classifications of impression material?
what are the two types of hydrocolloid?
-reversible and irreversible
give an example of a reversible hydrocolloid?
give an example of irreversible hydrocolloid?
what features do reversible and irreversible hydrocolloids both have in common?
-both colloidal suspensions of polysaccharides in water
what is agar?
-complex polysaccharide derived from seaweed
give examples of mucostatic materials?
what are some alternatives to impressions?
-Intra oral scanner
what are 4 types of elastomeric impression material?
2.silicon rubbers(condensation curing)
3.silicon rubbers(addition curing)
what is the byproduct of silicon rubbers (condensation curing)?
what is the by product of silicone rubber (addition curing)?
-there is no by product
what are the 3 products of gypsum?