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DENT1124 > Dental Materials Final Exam > Flashcards

Dental Materials Final Exam Flashcards

1
Q

What is model plaster used for?

A

pouring preliminary impressions to make diagnostic models for case presentations

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2
Q

What is model plasters water to powder ratio?

A

100 g to 25-50 mL water

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3
Q

What is dental stone used for?

A

Making more durable and stronger diagnostic casts

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4
Q

What is dental stones water to powder ratio?

A

100 g to 30-32 mL water

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5
Q

What is high strength stone used for?

A

creating a diem which is used for wax patterns, crowns, bridges and indirect restoration

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6
Q

What is another term for model plaster?

A

Plaster of paris

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7
Q

What is another term for high strength stone

A

densite or improved dental stone

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8
Q

What is the water to powder ratio?

A

100 g to 19-24 mL water

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9
Q

what is gypsum is its unrefined state?

A

dihydrate form of calcium sulfate converted into a powered hemihydrate

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10
Q

what is the setting reaction when you mix gypsum with water?

A

the hemihydrate crystals dissolve in water and form clusters known as nuclei of crystalization

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11
Q

how will too much water affect the model?

A

mix will be thin and runny, taking longer to set and creating a weaker cast

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12
Q

how will too little water affect the model?

A

the mix will be difficult to mix resulting in a shorter working time

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13
Q

What is the anatomic portion of a model?

A

Created from the alginate impression and consists of the teeth and gums

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14
Q

what is the art portion of a model?

A

forms the base of the cast

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15
Q

what is the double pour method?

A

anatomic portion is poured first then a second mix of plaster is used to prepare the art protion

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16
Q

what is the box-and-pour method?

A

the impression is surrounded with a “box” made of wax and poured as one unit

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17
Q

what is the inverted pour method?

A

one large batch of plaster or stone is mixed and both portions of the model are poured as a single step

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18
Q

3 steps of polishing a plaster model?

A
  1. mix a slurry of gypsum and fill in any voids
  2. soak the model in a soapy solution for 24 hours
  3. dry the model and then polish with a soft cloth
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19
Q

what causes undercuts in the cast?

A

air bubbles, shape of the arch and ridge, carious lesions, fractured teeth

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20
Q

what should we do with undercuts in a cast?

A

fill with wax or other molding material

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21
Q

what does outlining the tray designate?

A

the area to be covered by the tray, its outlined in pencil and extends over the attached gingiva to the mucogingival junction

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22
Q

what is a spacer?

A

creates room for impression material

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23
Q

how do we create a spacer for the tray?

A

cut a length of baseplate wax, warm it and place it over the cast area of the tray

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24
Q

what is a spacer stops? how is it made?

A

allows for adequate impression material, done by cutting triangular or round holds cut out using a laboratory knife, the cut outs prevent the tray from seating too deeply into the arch

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25
What is the separating medium?
used so that the tray can be removed from the cast
26
what is the space removers purpose ?
so the adhesive will stick properly. a toothbrush can be used
27
Custom trays: what is self curing acrylic resins major advantage and disadvantage?
advantage: the resin is strong and easily adaptable disadvantage: the liquid monomer is very volatility and poses a hazard
28
Custom tray: what is light cured resin major advantage and major use?
advantage: provide excellent adaption of the model use: for any impression situation: edentulous, edentulous or partially edentulous
29
Custom tray: what is thermoplastic material? use?
uses heat and vacuum to shape a sheet of thermoplastic resin to a diagnostic model use: impression trays, mouth guards, provisional coverage
30
what are the two waxes deprived from minerals?
paraffin and ceresin
31
what is the wax derived from animal?
beeswax
32
what are the 4 waxes derived from plants?
candelila, carauba, gum dammar, rosin
33
Pattern Waxes: What is inlay casting wax?
hard brittle, used to create a pattern or indirect restoration of a model
34
Pattern Wax: What is casting wax? what is it used for?
used for single tooth indirect restorations and fixed bridges for casting metal portion of a partial denture
35
Pattern Wax: what is Baseplate Wax?
hard, brittle used to record occlusal rims for initial arch form, setting denture teeth and denture wax up
36
Processing Wax: What is boxing wax and what is it use?
soft, pliable with a smooth shiny appearance supplied in narrow strips (1 inch by 12 inch) use: to form a wall around a preliminary impression when pouring
37
Processing Wax: what is utility wax and what is its use?
supplied as various forms of beeswaxes, petrolatum and other soft waxes use: extends the borders of an impression tray, covers brackets in orthodontic brackets
38
Processing Wax: What is impression waxes? use?
supplied in sticks or blocks made of beeswax and resin very brittle but becomes sticky when heats use: creation of a wax pattern or joining acrylic resin
39
Impression Waxes: What is corrective impression wax?
used in the procedure of taking edentulous impressions
40
Impression Waxes: What is bite registration wax
softens under warm water, leaving an imprint of the teeth when the patient bites down
41
Why are liners and bases used?
can make a big difference in post operative sensitivity and long term pupal prognosis
42
When are liners and bases used?
in cavity preps that are small in circumference but deep
43
What should be used in an amalgam restoration with a shallow prepartion?
desensitizer, etching and bonding system
44
What should be used in an amalgam restoration with a moderately deep preparation?
base, varnish or desensitizer, etching/ bonding system
45
What should be used in an amalgam restoration with a deep preparation?
liner, base, varnish or desensitizer and etching/bonding system
46
What should be be used in a composite restoration in a shallow and moderately deep restoration?
etching. bonding system
47
what should be used in a composite restoration in a deep restoration?
liner and etching/bonding system
48
in a cavity preparation the more natural tooth structure that remains the ____ the tooth will be
stronger
49
What causes physical stimuli?
thermal and electrical
50
What causes mechanical stimuli?
hand-piece and trauma
51
What causes chemical stimuli?
acid from dental material
52
What causes biological stimuli?
bacteria from saliva
53
What is a cavity liner?
thin layer of material placed at the deepest portion of the dental preparation to provide pupal protection or dentin regeneration
54
what is the purpose of a cavity liner?
to protect pupal tissues from irritation caused by stimuli
55
How is a cavity liner applied?
ether a two paste system or light cured, placed with a dycal applicator
56
Where must cavity liners be placed?
placed only in the deepest dentin surface, NOT to be placed on enamel
57
what is a common cavity liner?
calcium hydroxide
58
why is a varnish used?
varnishes seal dentinal tubules, reduces micro-leakage and acts as a barrier to high acidic cements
59
where is varnish placed?
placed within the entire preparation
60
How is a varnish applied?
small disposable applicator
61
What can varnishes NOT be used with?
Composite resins and glass ionomers
62
What is a fluoride varnish?
gel like substance designed to release fluoride on enamel, root structure and dentin structures
63
What is a desensitizer?
used to treat and prevent hypersensitivity that a patient may experience from a newly placed restoration
64
How does a desensitizer work?
seals dentinal tubules
65
what is important to remember in the application of a desensitizer?
do not allow contact to soft tissues
66
What is a dental base?
used for deep preparations under the permanent restoration, it acts as an additional layer to protect the pulp
67
Dental Bases: What is a protective base?
protects the pulp from a large restoration
68
Dental Bases: What is a insulating base?
protects the pulp from thermal shock
69
Dental Bases: What is a sedative base?
soothe pulp that has been damaged by decay or irritation by mechanical stimuli
70
Dental Bases: Zinc Oxide Eugenol (ZOE): What type of base can ZOE be used as?
an insulating base or a sedative base
71
Dental Bases: Zinc Oxide Eugenol (ZOE): What can ZOE not be used under
composite resins, glass ionomers, or other resin restoration
72
Dental Bases: Why is Zinc Phosphate a good base?
because of its thermal insulation qualities
73
Dental Bases: Why is polycarboxylate a good base
non irritating to the pulp, providing a buffer or layer between the pulp and the restoration
74
Why is glass ionomer- vitrebond a good base?
compatible under composite resins and easy to manipulate
75
What is dental etchant used for? what does it look like?
dental etchant is normally a 35% phosphoric acid, it allows a better mechanical bond, gives the tooth a frosted appearance
76
What must be do after applying a dental etchant?
rinse completely
77
What is dental bonding?
The process of solid and/or liquid contact of one material with another at a single margin
78
What is the smear layer?
thin layer of debris that remains on the dentin after cavity preparation
79
how is the smear layer removed?
through etching (smear layer also opens dentinal tubules)
80
How is enamel bonding done?
can be self cured, dual cured, or light cured, removes the smear layer allowing bonding to stick. ex. orthodontic brackets
81
What is the use of dental cements?
to bond indirect restorations into place
82
what is an indirect restoration?
also known as cast restorations are created in a lab and then placed into mouth
83
what is a type I dental cement?
luting agents which include permanent and temporary cements
84
What is a type II dental cement?
restorative material, such as glass ionomers
85
What is a type III dental cement?
liners or bases placed within the cavity prep
86
what is a luting agent?
designed to act as an adhesive to hold an indirect restoration to the structure, can also be used to adhere brackets to the tooth surface
87
what is a permanent cement? example?
used for long term cementation of cast restorations, such as crown, bridged, laminate veneers and orthodontic fixed appliances
88
what is a temporary cement
used if the restoration needs to be removed at a later date
89
how can humidity affect dental cements?
exposure to warm temps or humidity can result in a loss of water from the liquid and additional moisture in the powder
90
do you dispense powder or water first?
powder first, to minimize the loss of water
91
do we wait unit it is time to mix before setting out the powder and water on the pad or complete it in advanced?
wait until ready to mix
92
Which dental cement creates heat and undergoes an exothermic reaction? what should this cement be mixed on?
zinc phosphate, mixed on a cool glass slab
93
What is a common brand of glass ionomer?
FUJU, 3M Luting, Duract
94
What is a type I glass ionomer?
for cementation of metal restoration and direct bonded orthodontic brackets
95
what is a type II glass ionomer?
designed for restoring area of erosion near the gingiva
96
What is a type III glass ionomer?
used as a liner and dentin bonding agent
97
What is a type IV glass ionomer?
used for pit and fissure sealants
98
What is a type V glass ionomer?
cementation of orthodontic brackets and bands
99
How does glass ionomer inhibit recurrent decay
slowly releases fluoride
100
Is glass ionomer good or bad for the pulp
generally causes less trauma or shock to the pulp than is caused by other cements

DENT1124 (2 decks)

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