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NBDE II > OPERATIVE Restoration of Teeth > Flashcards

OPERATIVE Restoration of Teeth Flashcards

1
Q

___ are effective disinfectants, provide cross-linking of any exposed dentin matrix and occlude dentinal tubules by cross-linking tubular proteins

A

sealers (aka desensitizers)

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2
Q

sealers provide occlusion of the dentinal tubules which limits the potential for ___

A

tubular fluid movement and resultant sensitivity

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3
Q

sealers are typically ___ solutions

A

aqueous

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4
Q

historically, ___ was used as a liner under amalgam restorations

A

copal varnish

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5
Q

what are some examples of desensitizers that some sealers contain?

A

gluteraldehyde, hydroxyethylmethacrylate (HEMA), benzalkonium chloride, or chlorhexidine

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6
Q

___ are thin layers of material used primarily to provide a barrier to protect the dentin from residual reactants diffusing out of a restoration, from oral fluids, or from both, which may penetrate leaky tooth-restoration interfaces

A

liners

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7
Q

what are some ways liners act as barriers?

A
  • contribute initial electrical insulation
  • generate some thermal protection
  • some formulations provide pulpal treatment
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8
Q

___ are used to cover a direct or near pulpal exposure and to line very deep areas of a tooth preparation in vital teeth

A

liners

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9
Q

___ and ___ are examples of typical liners used with direct restorations

A

calcium hydroxide and RMGI

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10
Q

___ are used to provide thermal protection for the pulp and to supplement mechanical support for the restoration by distributing local stresses from the restoration across the underlying dentin surface

A

bases

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11
Q

how thick should bases be?

A

1-2mm typically

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12
Q

additional bulk from a base affords ___ and ___ protection to the pulp under metal restorations

A

mechanical and thermal

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13
Q

___ or ___ are recommended as a base to overlay any calcium hydroxide liner that has been placed

A

RMGI or conventional glass ionomer cement

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14
Q

RMGI or conventional glass ionomer cement base provides additional strength to resist ___ in amalgam restorations, as well as protection of the liner from dissolution during ___ procedures

A
  • amalgam condensation pressure

- bonded

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15
Q

describe how to use bases and/or liners in amalgam restorations with shallow excavations

A
  • shallow excavation = remaining dentin thickness >2mm
  • use a dentin sealer/desensitizing agent such as gluma or G5
  • sealers/desensitizers replace the traditional use of copal varnish
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16
Q

describe how to use bases and/or liners in amalgam restorations with moderately deep excavations

A
  • remaining dentin thickness is 0.5-2mm
  • use light cured RMGI base, followed by a dentin sealer/desensitizing agent
  • objective is to provide 2mm of insulation between the restorative material and the pulp
  • this replaces the traditional approach of using a zinc oxide eugenol base material followed by a copal varnish
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17
Q

describe how to use bases and/or liners in amalgam restorations with deep excavations

A
  • noncarious (or mechanical) pulpal exposure less than 1mm in diameter or excataions where the remaining dentin thickness is <0.5mm
  • use a thin (0.5-0.75mm) layer of calcium hydroxide liner on the suspected exposure site followed by RMGI base to seal immediate site of exposure
  • objectives are to prohibit bacterial infiltration and protect the liner from dissolution
  • a dentin sealer/desensiziting agent or an appropriate amalgam bonding agent is placed on the remaining dentin
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18
Q

describe how to use bases and/or liners in composite restorations with shallow to moderately deep excavations

A
  • remaining dentin thickness is 0.5mm or more
  • no liner or base material is indicated
  • only a dentin bonding system along with the composite restorative material is needed
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19
Q

describe how to use bases and/or liners in composite restorations with deep excavations

A
  • noncarious (or mechanical) pulpal exposure <0.1mm in diameter or excavations where the remaining dentin thickness is judged to be <0.5mm
  • use a thin (0.5-0.75mm) layer of calcium hydroxide liner placed on the suspected exposure site followed by RMGI base and the proper application of a bonding agent along with the composite restorative material
  • objective is to prevent bacterial infiltration while avoiding dissolution of the liner
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20
Q

describe how to use bases and/or liners in indirect restorations with shallow excavations

A
  • remaining dentin thickness is 2mm or greater
  • no sealer, liner, or base is needed
  • RMGI cement or a resin-based cement may be used for cementation, providing excellent dentinal sealing
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21
Q

describe how to use bases and/or liners in indirect restorations with moderately deep excavations

A
  • remaining dentin thickness 0.5-2mm
  • RMGI or conventional glass ionomer cement may be used to restore axial or pulpal wall contour and to ensure an adequate thermal barrier
  • objective is to provide 2mm of insulation between the restorative material and the pulp
  • RMGI or resin based material is recommended for cementation
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22
Q

describe how to use bases and/or liners in indirect restorations with deep excavations

A
  • noncarious (mechanical) pulpal exposure less than 1mm in diameter or excavations where remaining dentin thickness is <0.5mm
  • use a thin (0.5-0.75mm) layer of calcium hydroxide liner placed on the suspected exposure site followed by RMGI base to restore axial or pulpal wall contour, ensure an adequate thermal barrier, and seal the exposure site
  • objective is to prevent bacterial infiltration while avoiding dissolution of the base
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23
Q

in indirect restoration cases where pulp exposures occurred during preparation, where there is an increased risk of endodontic complications secondary to the pulp exposure, strong consideration should be given to performing ___ before completion of the indirect restoration

A

endodontic therapy

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24
Q

what are the two types of amalgams?

A
  • low copper (generally inferior, seldom used)

- high copper (spherical and admix)

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25
Q

is spherical or admix amalgam better? why?

A
  • admix

- less leakage and less postoperative sensitivity

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26
Q

the linear coefficient of thermal expansion of amalgam is ___ than that of tooth structure

A

greater

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27
Q

the compressive strength of high copper amalgam is ___ than tooth structure

A

similar

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28
Q

the tensile strength of high copper amalgam is ___ than tooth structure

A

lower

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29
Q

amalgams are brittle and have ___ edge strength

A

low

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30
Q

high copper amalgams exhibit ___ creep or flow

A

no clinically relevant creep or flow

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31
Q

is amalgam a high or low thermal conductor?

A

high

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32
Q

what are the clinical disadvantages of amalgam?

A

marginal fracture, bulk fracture, and secondary caries

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33
Q

what are the uses for amalgam restorations?

A
  • nonesthetic cervical lesions
  • large class I and II preparations where heavy occlusion would be on the material
  • class I and II preparations where isolation problems exist for bonding
  • temporary or caries-control restorations
  • foundations
  • patient sensitivity to other materials
  • where cost is a factor
  • inability to do a good composite
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34
Q

what are the advantages of amalgam?

A

strength, wear resistance, easy to use, less technique-sensitive, self-sealing margins over time, history of use, lower fee, long-term clinical longevity

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35
Q

what are the disadvantages of amalgam?

A

not esthetic, conductivity, tooth preparation more demanding and less conservative

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36
Q

is there scientific evidence that amalgam poses health risks to humans?

A
  • no, with the exception of rare allergic reactions

- there is actually no evidence ensuring that alternative materials pose a lesser health hazard

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37
Q

true amalgam allergies are rare. how many have been reported since 1900?

A

50

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38
Q

what is the estimate of human uptake of mercury vapor from amalgams?

A

5 ug/m^3

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39
Q

which amalgam type is likely to produce a more successful restoration?

A

high copper

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40
Q

how thick does amalgam need to be to increase its success?

A

1-2mm

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41
Q

after the tooth preparation for most amalgam restorations, a ___ is placed on the prepared dentin before amalgam insertion to ___

A
  • sealer
  • occlude the dentinal tubules
  • this step may occur before or after the matrix application
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42
Q

what are the 4 objectives of a matrix?

A
  • provider proper contact
  • provide proper contour
  • confine the restorative material
  • reduce the amount of excess material
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43
Q

what are the 4 characteristics a matrix needs to be effective?

A
  • be easy to apply and remove
  • extend below the gingival margin
  • extend above the marginal ridge height
  • resist deformation during material insertion
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44
Q

in terms of trituration, what two features affect the setting reaction of the material?

A

the speed and time of the mix

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45
Q

of spherical and admixed (lathe-cut) amalgam, which is easier to condense?

A

spherical

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46
Q

how is floss used to to check the proximal contact of an amalgam restoration?

A
  • insert floss inter proximally first by wrapping the floss around the adjacent tooth and pulling it through
  • wrap floss around restored tooth and move it occlusally and gingivally to determine if excess material exists and to smooth it
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47
Q

how do you repair an amalgam restoration?

A

-the defective area must be prepared again as if it were a small restoration, with appropriate depth and retention form

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48
Q

what are the causes of postoperative sensitivity from amalgam restorations?

A
  • lack of adequate condensation, especially lateral condensation in the proximal boxes
  • lack of proper dentinal sealer or pulp protection
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49
Q

what are the causes of marginal voids from amalgam restorations?

A
  • inadequate condensation

- material pulling away or breaking from the marginal area when carving bonded amalgam

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50
Q

what are the causes of marginal ridge fracture of amalgam restorations?

A
  • axiopulpal line angle not rounded in class II tooth preparations
  • marginal ridge left too high
  • occlusal embrasure form incorrect
  • improper removal of matrix
  • overzealous carving
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51
Q

are amalgam restorations safe?

A
  • yes, as reported by the US Public Health Service

- proper handing of amalgam is of vital importance

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52
Q

which type of high-copper amalgam provides higher earlier strength and permits the use of less pressure? which one permits easier proximal contact development because of higher condensation forces?

A
  • spherical

- admixed

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53
Q

are bonded amalgam restorations recommended?

A
  • not any longer
  • however, if bonding an amalgam, the use of typical secondary retention form preparation features are still required
  • small to moderate amalgam restorations should not be bonded
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54
Q

what are the indication for proximal retention locks?

A
  • may be beneficial for large amalgam restorations (not necessary for smaller restorations)
  • correct placement of proximal retention locks is difficult
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55
Q

what are the advantages of bonding to tooth structure?

A

less micro leakage, less marginal staining, less recurrent caries, less pulpal sensitivity, more conservative tooth preparation, improved retention, reinforcement of remaining tooth structure, and more conservative treatment of root-surface carious lesions

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56
Q

what are the uses of adhesive techniques?

A

change shape and color of anterior teeth, restore class I-VI lesions, improve retention for metallic or PFM crowns, bond ceramic restorations, bond indirect composite restorations, seal pits and fissures, bond orthodontic brackets, bond periodontal splints, bond conservative tooth-replacement restorations, repair existing restorations, provide foundations for crowns or onlays, desensitize exposed root surfaces, impregnate dentin and enamel to make them less susceptible to caries, bond fragments of anterior teeth, bond prefabricated and cast posts, and reinforce remaining enamel and dentin after tooth preparation

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57
Q

what is sufficient to etch enamel?

A

10-15 second acid etch (30-40% phosphoric acid) is sufficient

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58
Q

is micro leakage common at etched enamel margins?

A

no, it is virtually nonexistent

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59
Q

enamel bonding resists ___ forces of composite

A

polymerization shrinkage

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60
Q

how is dentin bonding accomplished?

A

either etch and rinse (simultaneous with enamel etch) or self etch (with a self etching primer or all in one adhesive)

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61
Q

how does dentin bonding compare to enamel bonding?

A
  • less reliable, less durable, and not as predictable as enamel bonding
  • may have some micro leakage, especially after aging of the restoration
  • may have similar or higher bond strengths than enamel
  • may not resist polymerization shrinkage forces
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62
Q

what are the factors that affect the ability to bond to dentin vs enamel?

A
  • microstructural features of enamel and dentin
  • material factors
  • preparation factors
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63
Q

describe the difference in composition of enamel vs dentin

A
  • enamel is 90% mineral (hydroxyapatite)

- dentin is much less mineral and more organic (type I collagen) and water

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64
Q

are enamel prisms and inter prismatic areas etched and bondable?

A

yes

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65
Q

what are the 3 types of dentin tubules?

A

peritubular, intratubular, and intertubular channels

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66
Q

dentin tubules extend from the ___ to the ___

A

pulp to the DEJ

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67
Q

what do dentin tubules contain?

A

odontoblastic extensions and fluid

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68
Q

how do dentin tubules range in size/number as they near the pulp?

A
  • much larger (2.4um) and numerous (45,000/mm^2) near the pulp
  • near DEJ (0.6um, 20,000mm^2)
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69
Q

fluid movement inside dentin tubules is dictated by ___

A

pulpal pressure

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70
Q

dentin that is aging, below a caries lesion, or exposed to oral fluids exhibits increased mineral content (sclerosis) and is much more resistant to ___

A
  • acid etching

- therefore, the penetration of dentin adhesive is limited

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71
Q

what is the smear layer?

A
  • debris left on the surface after cutting
  • consists of hydroxyapatite and altered denatured collagen and fills the orifices of the tubules (smear plugs), decreasing dentin permeability by 86%
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72
Q

how is the smear layer removed?

A

etching removes the smear layer, resulting in greater fluid flow onto the dentinal surface, which may interfere with adhesion

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73
Q

how is the linear coefficient of thermal expansion of dentin altered when subjected to thermal changes compared to composite?

A

dentin is 4x less than composite

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74
Q

composites shrink when they polymerize, creating stresses up to ___ megapascals

A

7 (1MPa = 150lb/in^2)

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75
Q

preparations with multiple walls or boxlike shapes (configuration) have limited ___ opportunity for the composite material (polymerization shrinkage), and the high configuration factor (C factor) may result in ___ and ___

A
  • stress relief

- internal bond disruption and marginal gaps

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76
Q

C factor is determined by the ratio of ___ vs ___ within a tooth preparation

A

prepared (bonded) vs unprepared (unbounded) walls

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77
Q

high C factor may indicate increased chance for ___

A

postoperative sensitivity

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78
Q

what are the two current adhesive systems used for bonding?

A

etch and rinse, and self etch

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79
Q

etch and rinse is also called ___

A

total etch (etch enamel and dentin)

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80
Q

what are etch and rinse three step systems?

A
  • aka multibottle or fourth gen systems

- etch, primer, and adhesive

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81
Q

what is the purpose of etch?

A

demineralizes enamel and dentin selectively, increases surface area, and cleans the surface of debris

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82
Q

T or F:

etched enamel and dentin appear chalky

A
  • false

- enamel appears chalky, but dentin does not

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83
Q

etched dentin exposes a layer of ___

A

collagen

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84
Q

what is the purpose of etch, primer, and adhesive?

A
  • etched dentin exposes a layer of collagen
  • primer increases the collagen
  • adhesive flows between the collagen and interlocks with it to form a sandwich (or hybrid or resin-reinforced) layer
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85
Q

most bond strength is from the formation of the ___ layer

A
  • hybrid (aka sandwich or resin-reinforced)

- the surface layer is only a few microns thick, creating a demineralized layer of dentin intermingled with resin

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86
Q

etch and rinse three step (etch, primer, and adhesive) systems ___ the dentin, which decreases ___

A

seals, postoperative sensitivity

87
Q

etch and rinse three step systems provide good dentin bonding strengths. how does it compare to enamel bonding?

A

same or better

88
Q

there must be a bond strength of ___ MPa to resist polymerization contraction force of composite

A

17-21

89
Q

how long should you etch enamel and dentin?

A

10-15 seconds

90
Q

what does etching enamel and dentin do?

A
  • etches enamel
  • removes smear layer
  • opens and widens dentin tubules
  • demineralizes dentin surfaces
  • etches out mineral (hydroxyapatite) but leaves collagen fibrils (these have low surface energy)
91
Q

what are the 4 steps for etch and rinse three step systems (from application to composite placement)?

A
  1. etch enamel and dentin for 10-15 seconds
  2. rinse well and leave moist or rewet (aqua prep or gluma desensitizer)
  3. apply 2-3 layers of primer HEMA/biphenyl dimethacrylate
  4. apply adhesive (bonding agent) - bisphenol A-glycidyl methacrylate or other methacrylate
  5. place composite
92
Q

what is HEMA/biphenyl dimethacrylate?

A
  • resin monomer wetting agent
  • dissolved in acetone, ethanol, and water
  • bifunctional
  • acts as a solvent
93
Q

how is HEMA/biphenyl dimethacrylate bifunctional?

A
  • wets dentin (increases surface tension)

- bonds to overlying resin

94
Q

adhesives may also contain HEMA or other primer constituents to enhance ___

A

bonding

95
Q

adhesives (bonding agents) penetrate ___, provide a ___ surface layer, and bond ___

A
  • intertubular dentin and tubules
  • polymerized surface layer
  • primer and composite
96
Q

what are etch and rinse two step systems?

A
  • aka one bottle or fifth generation systems

- primer and adhesive are combined but still need etchant

97
Q

in etch and rinse two step systems, primer and adhesive are ___

A

combined

98
Q

etch and rinse two step systems require etchants in order to ___

A

remove the smear layer

99
Q

most etch and rinse two step systems require ___ bonding

A

wet

100
Q

the bond mechanism of etch and rinse two step systems is ___

A

the hybrid layer formation

101
Q

how does the bond strength of etch and rinse two step systems compare to multibottle systems?

A

generally not as high, but this is likely not clinically significant

102
Q

T or F:

etch and rinse two step systems are very technique sensitive, and manufacturer’s instructions must be followed exactly

A
  • true

- must have dentin wettability just right

103
Q

etch and rinse two step systems are used primarily for ___ procedures

A

direct

104
Q

T or F:

etch and rinse two step systems are faster than multibottle materials

A

false

105
Q

what are the steps in the etch and rinse two step systems?

A
  1. etch for 10 seconds
  2. rinse well and leave moist or rewet
  3. apply 2-3 layers of primer/adhesive, thin gently with air, and light cure
  4. reapply adhesive, thin, and light cure
  5. place composite
106
Q

the objective or self etching systems is to remove ___

A

operator variables (rinsing and drying)

107
Q

what do self etching systems include?

A

etchant and primer, or etchant, primer, and adhesive combined

108
Q

what is the possible reason why self etching systems leave less postoperative sensitivity?

A

they do not completely remove the smear layer

109
Q

why do self etching systems need to be refrigerated?

A

reactive components

110
Q

why should you avoid using diamond burs when using self etching systems?

A
  • because they have a much thicker smear layer, which makes bonding more difficult because self etching systems do not completely remove the smear layer
  • use carbide burs
111
Q

T or F:

self etching systems etch enamel comparatively to phosphoric acid

A
  • false
  • they do not etch enamel as well as phosphoric acid
  • enamel etching with phosphoric acid may be beneficial, but do not etch dentin because it decreases the dentin bond
112
Q

why should self etching systems be air dried?

A
  • the material has water and needs to have a longer drying time to remove the water
  • dry for at least 10 seconds
113
Q

of the self etch categories, which is the most “risky”?

A

self etch one step systems (aka all in one)

114
Q

do self etch one step systems remove the smear layer?

A

no

115
Q

T or F:

self etch one step systems are very easy to use

A

true

116
Q

self etch one step systems provide a bond to dentin of ___ MPa

A

25 (not great)

117
Q

what is self etch two step?

A

self etch primer and then a bonding adhesive

118
Q

self etch two step requires how many coats?

A

about 5

119
Q

do self etch two step systems remove the smear layer?

A

no

120
Q

are self etch two step systems easy to use?

A

yes, fast and easy

121
Q

T or F:

self etch two step systems do not require rinsing

A

true, no worry about moisture

122
Q

is postoperative sensitivity common with self etch two step systems?

A

no

123
Q

self etch two step systems do not bond well to ___

A
  • uncut enamel (12 MPa)

- must roughen enamel and consider etching

124
Q

what are the advantages of self etch systems?

A
  • easy to use
  • eliminates variables with wet bonding
  • depth of etch is self limiting
  • sensitivity is reduced
125
Q

what are the disadvantages of self etch systems?

A
  • bond strengths to enamel and dentin generally lower
  • some do not adequately etch uncut enamel
  • bond strengths to autocuring composites are poor
  • clinical performance is not proven
  • bond durability questionable
126
Q

what are some important technique suggestions for etch and bond systems?

A
  • use microbrushes to apply primer/adhesive
  • place bonding agent in a small well to minimize evaporation
  • replace caps quickly and tightly
  • dispense 1-2 drops for each tooth
127
Q

what are important techniques for optimum bond?

A
  • proper isolation
  • roughen sclerotic dentin (increases surface area and removes some of the sclerotic dentin)
  • may still need mechanical retention
  • bevel or roughen and etch enamel
  • must have dentin moist (or rewet) for etch and rinse systems
  • dispense adhesives just before use
  • apply and dry primer adequately
128
Q

what happens if you dispense adhesive too long before use?

A

the solvent evaporates

129
Q

what happens if you don’t apply and dry primer adequately?

A
  • may have gross leakage and postoperative sensitivity (gently dry with air syringe)
  • too much primer is better than too little
130
Q

what happens if bonding agent (adhesive) is over-thinned?

A

may get an air-inhibited layer only, and it does not bond as well

131
Q

laboratory results of resin-dentin bonds show a loss of bond strength over time. why?

A
  • possibly from hydrolysis of the adhesive resin or the collagen fibers, or both
  • all in one types show the worst results
132
Q

bond durability is much greater when the peripheral margin is all in ___

A

enamel

133
Q

dentin and enamel bonding strength are ___ for most etch and rinse systems

A

similar

134
Q

most etch and rinse adhesive systems bond better to ___ dentin

A

moist (leave dentin moist or remoisten with water or a sealer/desensitizer)

135
Q

one bottle systems may be simpler but are not better; ___ systems may still be best

A

three step

136
Q

dentin variability, including ___, remains a problem in dentin bonding

A

sclerosis, tubule size, and tubule location

137
Q

enamel bonding is ___, ___, and ___

A
  • fast, strong, and long lasting

- dentin bonding may be strong, but may not be long lasting

138
Q

what are the 7 types of composite material?

A
  • macrofilled
  • microfilled
  • hybrid (midifill, minifill)
  • microhybrid
  • nanofilled/nanohybrid
  • flowable
  • packable
139
Q

what is the average particle size of macrofilled composites?

A

10um

140
Q

macrofilled composites are ___ generation restorative composites

A

first

141
Q

how do macrofilled composites cure?

A

chemical cure

142
Q

macrofilled composites have poor ___ and ___ properties

A

physical and mechanical

143
Q

describe shade matching with macrofilled composites

A
  • limited shade matching capabilities

- poor esthetics

144
Q

what is the average particle size for microfilled composites?

A

0.04um (40 nm)

145
Q

how are microfilled composites cured?

A

light cured

146
Q

describe the fracture toughness of microfilled composites

A
  • suboptimal

- not strong for occlusal bearing areas

147
Q

describe the esthetics of microfilled composites

A
  • excellent esthetics and polishability

- use primarily in anterior restorations

148
Q

microfilled composites have a lower ___, so it is better in class V situations

A

elastic modulus

149
Q

what is the average particle size of hybrid (midifill, minifill) composites?

A

1um (0.001mm)

150
Q

how are hybrid composites cured?

A

light cured

151
Q

hybrid composites have good properties and good esthetics, but are not as ___ as microfills

A

polishable

152
Q

what are the best uses of hybrid composites?

A

universal - good in anterior and posterior restorations

153
Q

what is the average particle size of microhybrid composites?

A

0.4-0.8um (400-800nm)

154
Q

how are microhybrid composites cured?

A

light cured

155
Q

microhybrids retains good properties of hybrids (___), with improved ___

A
  • strength

- handling

156
Q

the polishability of microhybrids is almost equal to ___

A

microfills

157
Q

what are the best uses of microhybrid composites?

A

universal use - good in anterior and posterior restorations

158
Q

what are the filler characteristics of nanofilled/nanohybrid composites?

A

vary with brand but typically 20nm nanomers and 0.6-1.5um nanoclusters

159
Q

how are nanofilled/nanohybrid composites cured?

A

light cured

160
Q

nanofilled/nanohybrid composites have excellent ___, are highly ___, and have low ___

A
  • handling
  • polishable
  • shrinkage
161
Q

what are the uses of nanofilled/nanohybrid composites?

A

anterior and posterior restorations

162
Q

what is the ratio of content in flowable composites?

A

high matrix/filler ratio

163
Q

flowable composites have higher ___

A

polymerization shrinkage

164
Q

packable composites have increased ___

A

viscosity

165
Q

what are the benefits of packable composites?

A

no documented benefits

166
Q

what are the properties of composite materials (coefficient of thermal expansion, water absorption, polymerization shrinkage, wear resistance, surface texture)?

A
  • high coefficient of thermal expansion
  • high water absorption
  • all composites undergo polymerization shrinkage
  • wear resistance has improved substantially with research and development
  • surface texture is a function of filler size (smaller = smoother) and type
167
Q

what does the high coefficient of thermal expansion of composites result in?

A

percolation, recurrent caries, and stain

168
Q

what does the high water absorption of composites result in?

A

deterioration of material

169
Q

describe the clinical performance of composite materials

A
  • marginal fracture (microfilled composites)
  • bulk fracture is rare
  • secondary caries
  • wear when used in heavy occlusal load areas
  • marginal leakage is heavily dependent on bonding
170
Q

are chemical (auto) cured composites still used?

A

no

171
Q

what are the advantages of light cured composites?

A
  • controlled insertion time
  • less finishing time required
  • less porosity
172
Q

what are the 2 types of curing lights?

A
  • quartz/tungsten/halogen

- light-emitting diode lights are more promising light systems available today

173
Q

what are the uses of composite materials?

A

class I-VI restorations, sealants, esthetic enhancements, hypocalcified areas, partial veneers, full veneers, anatomic additions, resin bonded bridges, luting agent, diastema closure, foundation

174
Q

what are the advantages of composite materials?

A

esthetics, insulation, bonding to tooth structure, conservation of tooth structure, less mechanical retention form needed, strengthening of remaining tooth structure, minimal to no microleakage

175
Q

how do composite materials strengthen remaining tooth structure?

A

reinforcement of remaining tooth structure by bonding (believed to be temporary)

176
Q

what are the advantages of minimal to no microleakage provided by composite materials?

A

decreased interfacial staining, recurrent caries, or postoperative sensitivity

177
Q

what are the disadvantages of composite materials?

A
  • wear potential (only when all occlusal contact on composite)
  • technique sensitive (dry field, difficult to do, takes more time)
  • polymerization shrinkage (may cause contraction gaps on root surfaces between composite and root)
  • sensitivity caused by C factor (especially in class I lesions)
178
Q

what are the 4 requirements for a successful composite restoration?

A
  • etched or primed enamel and dentin and adhesive placement
  • all occlusion should not be on composite
  • must not contaminate operating area
  • adequate technical skill
179
Q

all composite restorations are bonded with a ___. a liner or base (or both) may be needed depending on ___. when a matrix is used, typically the ___ is placed before matrix placement, and the ___ is placed after matrix placement.

A
  • dental adhesive
  • remaining dentin thickness
  • liner/base
  • dental adhesive
180
Q

what are the objectives of a matrix?

A
  • provide proper contact and contour
  • confine restorative material
  • reduce amount of excess material
181
Q

what are the characteristics a matrix should have to be effective?

A
  • easy to apply and remove
  • extend below the gingival margin
  • extend above the marginal ridge heigh in posterior restorations and the incisal edge in anterior restorations
182
Q

proper incremental placement of composite is important to ensure what two things?

A
  • adaptation to tooth preparation and margins

- avoid voids or gaps in between increments

183
Q

what are two options for composite insertion instruments?

A
  • composite hand instruments (metal or plastic)

- syringe

184
Q

composite should be placed in incremental portions because light only cures to ___mm depth in most composite curing units

A

2-3mm

185
Q

composite light cure time depends on the manufacturer and varies depending on what 3 things?

A

composite type, shade, and opacity

186
Q

what should be used to remove gross excess composite after curing? what should be used to obtain proper contour?

A
  • medium-coarse diamond instruments

- fine diamond finishing instruments, 12-bladed carbide finishing burs, and abrasive finishing discs

187
Q

what is the difference between an inlay and an onlay?

A
  • inlays are intracoronal indirect restorations

- onlays are intracoronal indirect restorations that cover all cusps

188
Q

what are the advantages of gold inlay and onlay restorations?

A
  • excellent track record
  • good fit
  • excellent method to restore occlusal relationship
  • structurally sound material
189
Q

what are the disadvantages of gold inlay and onlay restorations?

A
  • nonesthetic
  • complicated tooth preparation
  • complicated marginal finishing
  • need adequate laboratory support
  • cost
190
Q

what are the indications for a gold inlay/onlay?

A

large occlusal surface needs, tooth contour needs, fractures, splinting, bracing for teeth with RCT, bridge retainers, partial retainers

191
Q

what are the requirements for a successful gold onlay?

A
  • tooth preparation
  • lab fabrication
  • cementation
192
Q

describe the tooth preparation for a gold onlay restoration

A
  • removal of weakened tooth structure
  • divergence of the external surface of 2-5 degrees per prepared wall
  • beveled finish lines
  • pulpal protection
  • soft tissue management
193
Q

in gold onlay preparations, what are some causes of inadequate soft tissue management?

A
  • careless, traumatic preparation
  • poor fitting temporary
  • temporary cement irritation
  • careless use of retraction cord
194
Q

in gold onlay preparations, what are some problems resulting from bleeding or unhealthy tissues?

A
  • access and vision impairment
  • impression difficulty
  • temporary fabrication difficulty
  • cementation difficulty
195
Q

what are important considerations for lab fabrication of gold inlays and onlays?

A
  • accurate impression
  • appropriate waxing
  • adherence to lab protocol
196
Q

what are the most important aspects of successful cementation of gold inlays and onlays?

A
  • adequate marginal finishing

- proper manipulation of luting agent

197
Q

what are the characteristics for incorporation of draw/draft in gold inlay/onlay tooth preparations?

A
  • 2-5 degrees per wall
  • the longer the wall, the greater the amount of draw/draft
  • must draw for casting to seat on tooth
  • more parallel = more retention
198
Q

what is primary retention provided by in gold inlay/onlay preparations?

A
  • draw/draft

- length of longitudinal (vertical) walls

199
Q

what is secondary retention provided by in gold inlay/onlay preparations?

A
  • retention grooves (proximally)
  • skirts
  • groove extensions
200
Q

what are the objectives for beveled margins on gold inlay/onlay preparations?

A
  • good fit of gold to tooth
  • strong tooth margin (usually strongest enamel margin)
  • burnishable gold margin
201
Q

describe burnishable gold margins in gold inlay and onlay restorations

A
  • can bend a 30-50 degree gold margin
  • less than 30 degrees may be too thin and may break
  • greater than 50 degrees may be too thick and will not bend
202
Q

what are pulp protection options for gold inlay and onlay restorations?

A
  • liners, bases, and build-ups

- must be retained in preparation for impression, temporary, try-in, and cementation

203
Q

describe occlusal extensions in gold inlay/onlay preparations

A
  • cap cusps as soon as possible (use depth cuts, removes weakened tooth structures, increases access and visibility)
  • preserve noncapped cusps
  • preserve noninvolved marginal ridges
  • smooth outline form
204
Q

describe wall design in gold inlay/onlay preparations

A
  • use #271 bur
  • 2-5 degree taper per wall
  • increased wall height increases retention
  • increased draw decreases retention
205
Q

describe proximal box design in gold inlay/onlay preparations

A
  • gingival extension to include all faults and obtain clearance with adjacent tooth
  • draw (2-5 degrees)
  • facial and lingual extensions to include all faults and obtain clearance with adjacent tooth
  • cavosurface margin 30-40 degrees
  • blend with other bevels
206
Q

what are the general rules for margination and bevels in gold inlay/onlay preparations?

A
  • use fine diamond

- cut dry for final marginating for better vision

207
Q

describe the design of the occlusal bevel in gold inlay/onlay preparations

A
  • 0.5mm width
  • 40 degree gold margin
  • on occlusal surface
  • may not need bevel because angulation of the facial and lingual cusps may provide for the fabrication of a 40 degree gold margin without preparation
  • lingual/facial groove extension bevel should also be 0.5mm width and 40 degree gold margin
208
Q

describe the cusp counterbevel design in gold inlay and onlay preparations

A
  • 0.5-1mm width
  • 30 degree gold margin
  • for nonesthetic capped cusps
209
Q

describe the stubbed margin design in gold inlay and onlay preparations

A
  • 0.25-0.5mm width
  • perpendicular to long axis of the crown
  • for esthetic capped cusps
210
Q

describe the secondary flare design in gold inlay and onlay preparations

A
  • extends facial and lingual proximal margin into facial and lingual embrasure
  • 40 degree gold margin
  • diamond held perpendicular to long axis of preparation
  • occlusogingival width is not uniform
211
Q

describe the collar design in gold inlay and onlay preparations

A
  • beveled shoulder design around a capped cusp
  • provides bracing
  • shoulder prepared with #271 bur
  • 0.5mm bevel prepared with diamond
212
Q

describe the skirt design in gold inlay and onlay preparations

A
  • extends casting around line angle
  • increases retention form
  • increases resistance form
  • “minicrown prep”
  • use diamonnd
  • facial and lingual finish lines result in 40 degree gold margin
  • gingival finish line is a chamfer with a minimum depth (not uniform) of 0.5mm and extended into the gingival 1/3 of the crown
213
Q

describe the gingival bevel design in gold inlay and onlay preparations

A
  • 0.5-1mm width
  • 30 degree gold margin
  • all bevels must blend with each other

NBDE II (35 decks)

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