Denal materials Flashcards

1
Q

name the 6 different categories in materials

A

cermet, metallic, organo-metallic, polymers, composite, ceramics

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2
Q

what 2 mixed make composites?

A

ceramics and polymers

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3
Q

describe metals

A

high conductivity, luster, malleable, forms Cations when disolved

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4
Q

describe polymers

A

large molecule formed by many small ones

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5
Q

describe ceramics

A

inorganic & non-metallic, usually oxides but also sulfides ( glass is a type of ceramic)

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6
Q

describe composites

A

combination of ceramic powder and polymers

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7
Q

describe cermet

A

metal and ceramic powders combined

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8
Q

describe organometallic

A

dispersion of metal powders in a polymer, not common in dentistry

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9
Q

name the properties that are commonly tested for in dentistry

A

compression, tension, torsion, shear.

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10
Q

strength testing devices test what 2 things?

A

strain( change in dimension), stress( force/ area)

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11
Q

tensile tests test what

A

force/area, force pulling up and area being pulled

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12
Q

name some tests for bending

A

3 point, 4 point flexure test

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13
Q

shear testing is often used for what?

A

bonding

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14
Q

name the 3 adhesion mechanisms

A

mechanical, chemical, wetting/contact angle

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15
Q

torsion is important in what

A

tooth extraction, implant placement

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16
Q

describe fracture toughness

A

resistance to fracture when crack is present

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17
Q

describe elastic modulus

A

even slope= elastic, above is rigid, below is ductle

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18
Q

what is brittle?

A

no visible deformation before breaking

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19
Q

what is duclte?

A

visible deformation before breaking

20
Q

what is cyclic fatigue?

A

how many cycles its used until failure

21
Q

what is thermal cycling?

A

hot and cold baths alternating for fixed number of cycles. Then test bond strength, compare to strengths without cycling

22
Q

DPH

A

Diamond pyramid hardness. Tests the hardness of a material

23
Q

other ways to test hardness

A

Rockwell- conical

brinell- spherical

24
Q

wear resistance

A

abrasion- mechanical or scratching
chemical- erosion
3 body wear- includes material between 2 surfaces ( food)

25
Q

what is rheology

A

flow, viscous( honey,syrup) or non-viscous (water)

26
Q

rheology testing tells you if the material is…

A

Newtonian
pseudoplastic- flow increases with shear rate
dilatant- flow decreases with shear rate( silly putty)

27
Q

what is corrosion/tarnish?

A

electrochemical reaction of 2 metals, oxidation. It can affect all materials

28
Q

what is radiopacity?

A

absorption of x-rays ( white). It correlates with atomic weights of components

29
Q

heavy elements that are good include…

A

gold, silver, palladium, platiunum, tungsten, barium sulfate, bismuth oxide

30
Q

heavy but toxic include…

A

arsenic, mercury, tellurium, lead, antimony

31
Q

what is color metamerism?

A

2 material match under one light but don’t under another

32
Q

biocompatibility of materials depends on….

A

cytoxicity, allergenicity, irritation, implantation, mutagenicity

33
Q

results of cytotoxicity depend on what

A

cell line, direct contact, roughness of material, materials composition, reaction with medium,

34
Q

balance of cytotoxicity

A

mammalian cells- tolerate high PH

Bacteria- Anticeptic

35
Q

what is glass?

A

inorganic, non-crystalline, can be radiopaque, usually silica based

36
Q

is silica the same as silicone?

A

no, silicone is organic

37
Q

thermoplastic vs thermosetting

A

thermoplastic can be reformed

38
Q

common ceramic #1

A

zinc oxide, has antimicrobial properties. Also is a filler and reacts with salts to make restoratives

39
Q

common ceramic #2

A

calcium hydroxide, soluble in high ph. Also has High PH which is a antimicrobial property as well. It reacts with CO2 to form calcium carbonate ( which is seashells, snail shells, egg shells, coral, marble)

40
Q

organics

A

silicone- polymers of rotating Silicone and oxygen molecules with organic side groups

41
Q

terminology for metals

alloy, amalgam, stainless steel

A

alloy-combination of 2 metals,
amalgam- alloy of mercury used for dental fillings.
stainless steel- iron alloy with more that 10.5% Cr

42
Q

what is Ni-Ti used for?

A

nickel titatnium- used for endodontics and orthodontics since it is flexible

43
Q

what is straight titanium used for?

A

its very stiff and used for implants

44
Q

what is a micron?

A

1 millionth of a meter

45
Q

what is a nanometer?

A

1 billionth of a meter

46
Q

what is a nanoparticle?

A

have much higher surface to volume rations

47
Q

basic principle to remember

A

body temperature accelerates reactions, radiopacity relys on high atomic weights, acid plus base =salt