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D2 Fall - Operative III > 8/26: Lecture 2 - Adhesives and Bonding > Flashcards

8/26: Lecture 2 - Adhesives and Bonding Flashcards

1
Q

What is the purpose of beveling?

A

reduce microleakage at cervical and ascending walls in class 2

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2
Q

What does beveling expose?

A

ENDS of enamel rods = reveals prismatic enamel = etches better

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3
Q

What is the purpose of bevelling for axiopulpal?

A

Resistance by distributing stress

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4
Q

Where do you bevel?

A

in ENAMEL, NOT in deep preps where a bevel would remove all enamel or where gingival floor is on cementum/dentin

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5
Q

When should you NOT bevel?

A

in class 3 if heavy centric contact to margin

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6
Q

Where is a flare in a class 2 composite prep?

A
  • Buccal flared > 100
  • Lingual Flared > 90
    Buccal contact can remain in many cases
    Slight flare occlusal of prep
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7
Q

Where is a flare in a class 2 amalgam prep?

A

both exit angles are 90 degrees (need S curve on buccal to achieve)
- NEED to break buccal contact

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8
Q

Should you have a gingival bevel for amalgam?

A

NO

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9
Q

Where is a flare in a class 3 composite prep?

A
  • Internal Labial flare
  • Gingival flare to exit at 90 degrees
  • Labial wall flare of 100 degrees at cavosurface = exposes ends of enamel rods
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10
Q

What is the purpose of etch?

A

Increases surface wetting by increasing surface area available for bonding

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11
Q

What is surface wetting?

A

ability of liquid to maintain intermolecular contact with a solid surface

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12
Q

Etching
__________ free energy to _______ the surface tension of bonding material

A

raises; exceed

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13
Q

What spaces does etching produce?

A

Spaces where bond agent resin can penetrate and form resin tags

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14
Q

What layer does etching remove?

A

Smear layer

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15
Q

What is a smear layer?

A

Mixture of tooth debris, saliva, blood cells, bacteria and does NOT accept bond well

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16
Q

How do you use etch?

A

Place for 15 seconds, rinse for 10

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17
Q

What is primer?

A

hydrophilic (allows for binding to moist dentin and wetting of surface) monomers (like ethanol/water, acetone) to draw bond agent in

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18
Q

Is bond hydrophobic or hydrophilic?

A

Hydrophobic

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19
Q

What kind of binding does bond use?

A

micro-mechanical binding to interlock into surface irregularities

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20
Q

How does bond bind to enamel?

A

interlocking with enamel rods

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21
Q

How does bond bind to dentin?

A

interlocking with dentin collagen, which depends on MMPs

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22
Q

What is bond more predictable with?

A

Predictable with enamel (especially incisal and middle 3rd) but less with dentin as the bond strengths vary due to heterogeneity (very organic)

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23
Q

What system is etch separate frmo bond agent?

A

Etch and rinse (total etch)

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24
Q

What are the types of etch and rinse systems?

A

Primer and bond can be separate (3 step) or together (2 step)

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25
Q

What are pros of the etch and rinse system?

A

larger hybrid layer, adhesive can penetrate further, more predictable, stronger bond because enamel is adequately prepared

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26
Q

What is the hybrid layer?

A

micromechanical interlocking of demineralized intertubular collagen and resin, good for bonding to dentin

27
Q

How is the hybrid layer formed?

A

by etching, washing, primer, adhesive (resin), light cure

28
Q

What does overetching lead to?

A

Unprotected layer = underfilled restoration

29
Q

What does overdrying lead to?

A

Collagen collapse = lower bond strength

30
Q

What does underdrying lead to?

A

collagen is too wet = blister spaces where primer and adhesive separate

31
Q

What etch doesn’t have a separate etch step?

A

Self-etch

32
Q

Describe the self etch system

A

Acid is apart of the primer (2 step) or primer/bond (1 step: all-in-one)

33
Q

What is a con of self etch?

A

will NOT etch unprepared enamel, collagen degradation over time, lower bond strength

34
Q

What layer of the tooth does selective etch etch?

A

only etch the enamel NOT the dentin

35
Q

What layer of the tooth does complete etch etch?

A

enamel AND dentin

36
Q

What etch systems can universal adhesives be used with?

A

can be used with total etch, self-etch, and selective-etch
We use!!!!

37
Q

What is the game changer for universal adhesives?

A

10-MDP

38
Q

What does 10-MDP allow for?

A

Bonding to many surfaces

39
Q

Describe the chemical reaction of universal adhesives

A

Monomer (phosphate ester) chemically interacts via ionic bonding to calcium in hydroxyapatite

40
Q

What is the function of adhesive?

A

resin tags (macro and micro) interlock into surface irregularities

41
Q

What are the steps of a composite restoration?

A
  1. Etch for 20 seconds to enamel and 15 to dentin or selective etch
  2. Wash for 10 seconds and dry enamel and dentin lightly (moist)
  3. Apply primer (not with adhesive universal)
  4. Apply adhesive
  5. Light cure (470 nm) = initiate
  6. Place composite
42
Q

When should you re-etch?

A

if tooth gets contaminated with saliva, re-etch for 10 seconds, rinse and dry, until frosted ename

43
Q

Should you etch longer for fluoridated teeth?

A

YES because more resistant to acids

44
Q

How do you repair old composites?

A

roughen old composite with diamond bur, etch, wash, dry, bond, thin, cure, and add new composite

45
Q

What is the shape of type 1 enamel rods? from dissolution of what?

A

honeycomb; enamel rod cores

46
Q

What is the shape of type 2 enamel rods? from dissolution of what?

A

cobblestone; enamel rod peripheries

47
Q

Where are type I and type II enamel found?

A

In occlusal and middle thirds of teeth

48
Q

What enamel gives the BEST bond?

A

Type 1 and 2

49
Q

What kind of enamel tags does cervical enamel have?

A

Shorter and fewer

50
Q

What do shorter and fewer enamel tags create?

A

Less prism delineation

51
Q

What MPa does using adhesive result in?

A

20-25MPa

52
Q

What kind of MPa bond strength does perpendicular enamel have?

A

25 MPa

53
Q

Where is perpendicular enamel found?

A

ENDS of rods
- at cavosurface margin of class 1 prep and bevels of class 2 preps

54
Q

What kind of MPa bond strength does parallel enamel have?

A

7-10 MPa bond strength

55
Q

Where is parallel enamel found?

A

SIDES of rods
- in internal walls of occlusal preps and in gingival floor of box in Class 2 prep

56
Q

Is dentin more/less predictable with bonding?

A

LESS because its heterogenous

57
Q

Where do odontoblastic processes extend to?

A

Tubules

58
Q

Where is peritubular dentin?

A

Directly around tubule

59
Q

Is peritubular dentin organic or inorganic?

A

INorganic

60
Q

Where is intertubular dentin?

A

Between tubules

61
Q

Is intertubular dentin organic or inorganic?

A

ORGANIC

62
Q

What is intertubular dentin rich with?

A

Collagen = allows for bonding

63
Q

What are factors affecting bond to dentin?

A

Cavity depth, caries, moist/dry

D2 Fall - Operative III (11 decks)

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