stud
bud
Sign up
Log in
Home
Library
Explore
SAT
More
Biomaterials Test 1 Flashcards | StudBud
Explore
/
Biomaterials Test 1
Biomaterials Test 1
93 terms
·
StudBud Administration
·
35 plays
Imported from external platform
Flashcards
93 cards
F
Practice quiz
P
Host live
L
Questions
93
Answers
1
how to prevent pitting:
rinsing instruments thoroughly after use
avoiding long exposure to chlorides and acids
not mixing metals in ultrasonic cleaners
avoiding detergents with high pH
2
what are some ways to increase gypsum setting time?
lower water/powder ratio
increased mixing
addition of retarders
addition of accelerators
3
instruments should be cleaned immediatly if possible and if not then soaked in an enzymatic solution to prevent drying:
True
False
4
most popular impression materials used in the construction of bridges, crowns and precise restorations
alginate
addition silicones
5
The double-mix impression technique uses two different viscosities of impression material:
one has a low viscosity and is syringed on and around the tissues
One is very thick and is used in the tray
6
examples of nonaqueous elastomeric impression materials:
polyethers
alginate
addition silicones
condensation silicones
polysulfides(rubber or rubber base)
7
When two dissimilar metals are present in the mouth, galvanic corrosion may occur. Sometimes, this is called
pitting
oral galvanism
8
List the oral structures from which impressions are made:
tongue
teeth and gingiva
hard and soft palate
frenums
alveolar bone and residual ridges
9
When classifying by use, a dental material would be listed under one of the following categories:
polishing materials and preventative materials
cements and temporary materials,
restorations, crowns, bridges
impressions, casts/models
complete/partial dentures
implants and specialty materials
10
Plaster
water/powder ratio:
28 to 30mL/100g
19 to 24mL/100g
45to50mL/100g
11
produces a smooth chemical process that forms a thin layer of chromium oxide on the surface of the instrument
electropolishing
passivation
12
Alginate setting time for fast mix is in 1 to 2mins meaning working time is:
1 min
2 mins
13
Explain the difference between biomaterials and dental materials?
Biomaterials are man-made materials that are used to replace tissues
dental materials are biomaterials used in/or around the oral cavity
there is no difference, they are the same
14
is a chemical or electrochemical attack on a metal surface.
Tarnish
Corrosion
15
If a restoration is constructed on the replica, it is called a:
cast
diagnostic cast
study model
16
localized corrosion caused by a chemical and electronic attack on surfaces
pitting
spotting
17
is a process in which a metal is changed to a metal oxide: iron is changed to iron oxide, or rust.
corrosion
tarnish
18
Trays that have been tried/used for taking impressions should be sterilized b4 being returned to storage
False
True
19
which is the best indicator of the initial set of gypsum products:
loss of gloss
loss of resilience
decreased compressive strength
20
more uniform, less pours, stronger and more expensive than plaster, used for diagnostic purposed
improved stone
plaster
stone
21
the reasons for using addition silicone impression material.
does not need to be poured immediately
stable and accurate
easy to clean up
inexpensive
22
Which of the following sequence of steps is correct for the instrument maintenance cycle?
Sharpen, inspect, use and maintain, sterilize, wash/ultrasonic clean
Use and maintain, inspect, wash/ultrasonic clean, sharpen, sterilize
Use and maintain, sharpen, sterilize, inspect, wash/ultrasonic clean
Use and maintain, inspect, wash/ultrasonic clean, sterilize, sharpen
23
prepping the tray for addition silicone impression material:
apply adhesive, spray tray and place material
allow to air dry for 10 mins until adhesive is tacky
apply tray adhesive to facial, occlusal and lingual surfaces
24
Describe the use of impression materials during indirect restorative procedures:
referred to as a negative reproduction
used to study and in diagnosis and treatment planning
Used to make replicas
25
materials that gel by a physical change (cooling) are called:
agar(reversible hydrocolloid)
alginate(irreversible hydrocolloid)
26
Differentiate between a model, a cast, and a die:
replica of a single tooth = die
physical model of the oral tissues for study = study model
replication of size/shape of preparation to construct appliance = cast
27
The desirable strength of gypsum materials is_____related to the amount of water used.
directly
indirectly
28
Improved stone
water/powder ratio:
45to50mL/100g
28 to 30mL/100g
19 to 24mL/100g
29
List the desirable qualities of an impression material:
Elastic properties with freedom from permanent deformation after strain
adequate detail reproduction and tear strength
Acceptable odor, taste, esthetic color, Non-toxic and non-irritating
Adequate shelf life, affordable and easy to mix
30
important difference between types of elastomeric impression materials is the adhesive that is used to bond to the tray
True
False
31
For gypsum products, a suitable accelerator and retarder:
Oleic acid and glycerin
Potassium sulfate and borax
Ethyl alcohol and oleic acid
32
Explain how
FDA
evaluate and/or classify dental drugs, materials, instruments, and equipment
Class I-Least regulated. Prophy paste and brushes.
Class III-Most regulated! Require premarket approval. Bone graft material.
Class II- Composite and amalgam restorative materials
considers dental materials to be devices, of which there are three classes
33
causes of spotting:
insufficient rinsing after ultrasonic cleansing
not changing ultrasonic solution
insufficient drying after ultrasonic cleaning
sterilizer has not been cleaned
34
The chemical reaction that links the monomers together to produce a polymer (macromolecule) is called:
polymerization
activation
35
produces a smooth, highly polished finish.
electropolishing
passivation
36
identify classification of caries pictured:
class VI
class III
class IV
class I
class V
class II
37
why is it important to inspect your instruments?
assess for imbalance and monitor wear rates
to inspect for compromised conditions
to determine age of instruments
to evaluate the need for re-tipping, avoid detachment
38
Disadvantages of unsaturated chemical vapor includes
compressed steam conditions
odor and need for ventilation
39
wax with added filler to improve handling and stability.
impression compound
utility wax
40
rationale for dental hygienists to learn the preparation and technique of addition silicone impression material.
its the most commonly used material in the office
there may be a time when you are needed to assist when using this material
41
identify classification of caries pictured:
class I
class III
class II
42
overall combine height of both max/man models should be what inches:
2 to 2.5
1.5 to 2
43
process of heating gypsum and driving off part of the water of crystallization:
dehydration
calcination
44
identify classification of caries pictured:
class II
class III
class I
45
setting time for putty-wash material technique
3 to 5 mins
1 to 3 mins
5 to 7 mins
46
Name three ways dental materials may be classified:
by longevity
by location of fabrication
by color
by use
47
what are some ways to decrease setting time of gypsum?
addition of retarders
decreased mixing
increased mixing
higher water/powder ration
48
identify classification of caries pictured:
class I
class III
class II
49
What is the rationale for dental hygienist to have knowledge and understanding of dental materials?
to handle them properly (we place materials such as sealants)
to assess and treat the patient accordingly (recognizing restorations)
educate the patient (ex. how to take care of bridge)
to understand the behavior of the materials around oral tissues
to sell materials
50
from the mix to when it starts to harden (aka how long you have to work with it)
final setting time
inital setting time
51
identify classification of caries pictured:
class II
class VI
class III
class IV
52
estimated setting time of gypsum products:
30-45 mins
20-25 mins
53
5 Reasons to sharpen instruments are
improved calculus removal
improve tactile sensitivity
less chair time
reduced clinician fatigue
less pt discomfort
54
Corrosion in a wet environment, such as saliva, is an electrochemical process called
tarnish
galvanic corrosion
55
Contracts due to evaporation:
imbibition
syneresis
56
Slow or improper drying leaves mineral deposits that cause:
spotting
pitting
57
What is the results of an unbalanced instrument?
re-tipping
over sharpening
58
when taking an impression the mandibular arch should be taken from 7 o'clock and the maxillary from 11 o'clock
True
False
59
The dry heat method of sterilization is used when:
Items cannot withstand temperatures greater than 270°F
Items cannot withstand compressed steam conditions
60
identify classification of caries pictured:
class IV
class II
class I
class III
61
safety measures for laboratory procedures by OSHA:
removal of jewelry, loose clothing and long sleeves
turn on trimmer and establish even flow of water
no eyewear or protective wear is required
Don appropriate personal protective equipment and secure hair
62
steam autoclave is recommended for:
most instruments including resin instruments
only metal instruments
63
Describe the effect of water and heat on the setting rate of polysulfides.
no significant effects from water or heat
Water can be lost or evaporation causing distortion
heat significantly accelerates the working and setting times
64
Unsaturated chemical vapor is effective for:
resin instruments
all metal instruments. It is best suited for carbon steel instruments
65
most expensive, strongest, very dense, cuboidal particles, reduced surface area, mainly used for casts or dies for crown
plaster
stone
improved stone
66
Stone
water to powder ratio:
28 to 30mL/100g
45to50mL/100g
19 to 24mL/100g
67
three questions you should ask yourself if instruments need to be sharpened:
how many times a day did I or will I use a specific instrument
what degree of difficulty can I expect to encounter while using this
for what procedures did I or will I use the instrument
68
Explain how
ISO
evaluate and/or classify dental drugs, materials, instruments, and equipment
attempts to unify the standards of its member countries worldwide
sets the standards and guidelines for evaluating dental products
69
inelastic impression materials include:
ZOE
impression compound
plaster/stone
alginate
wax
70
strength that is measured when the sample contains some/all of the h20 excess of the amount required for hydration.
dry strength
wet strength
71
weak, cheap, pours, irregular particles, used when strength is not a critical requirement
plaster
improved stone
stone
72
Each tray should:
2- to 3-mm depth of alginate beyond the occlusal surface and incisal edge
extend 2 to 3 mm beyond the last tooth to include the retromolar area
Be comfortable for the patient.
Extend facially to include all teeth, musculature and vestibule
73
Absorbs water or liquids:
syneresis
imbibition
74
consist of iron, chromium and nickel; less likely to have corrosion but can be discolored and need sharpened often
Carbon Steel Alloy
Stainless Steel Alloy
75
rubber impression material with ether functional groups; has high accuracy and is popular for crown/bridge procedures
polysulfide
polyether
76
Luting agents are frequently called __. hold the crown onto the prepared tooth and fills in the microscopic gaps
base
liner
cement
77
disadvantage of hydrocolloids is that they are susceptible to syneresis and imbibition, which can affect accuracy
True
False
78
why would the double pour technique be preferred for fabricating a cast or model
the first pour would have set before the 2nd preventing distortion
it is quicker
79
material that has sulfur-containing (mercaptan) groups; it has also been referred to as rubber base impression material
polysulfide
polyether
80
Addition silicone material is best prepared
using latex gloves
in a moist environment
with two people
by a single operator
81
examples of aqueous elastomers:
polyethers
alginate
agar
polysulfides
82
Identify four characteristics or properties a dental material must possess to survive the oral environment.
Be compatible with human tolerance - not toxic
Not breakdown in an acidic, moist environment - corrosion
contract and expand similar to tooth structures - thermal changes
withstand chewing forces - mechanical properties
83
Slows down the setting of a concrete mix in order to allow more time for placing and working the mix.
retarder
accelerator
84
advantage(hydrocolloids)while being poured, the gypsum easily wets the surface of the hydrocolloid becuz its made of h20
True
False
85
Describe the various types of impression trays:
full arch: impression of the maxillary or mandibular arches of the mouth
quadrant trays: impressions of specific quadrant of mouth
custom trays: tray made special for the pt for a final impression
section trays: impressions of specific sections of the mouth
Bite registration tray: used to obtain occlusal registration of arches
86
Explain how
ADA
evaluate and/or classify dental drugs, materials, instruments, and equipment
Ensures the safety of all medical devices
sets the standards and guidelines for evaluating dental products
requirements for physical and mechanical properties are measured in a lab
87
some of the conditions that make the oral cavity a hostile environment:
Biting forces may fracture teeth and materials
degradation of teeth (caries) and materials (corrosion)
biocompatibility (harmful effects on patient)
temperature changes(contract/expand) causing sens or leakage
saliva
esthetic demands of the pt
88
known for their hardness and ability to hold sharp cutting edge but are suceptible to corrosion:
Carbon Steel Alloy
Stainless Steel Alloy
89
estimated working time of gypsum products
5-7 minutes
8-10 minutes
90
from the mix to when it is completely hardened (aka how long until it is complete)
inital setting time
final setting time
91
when should the instruments be sharpened?
after sterilization, immediately before use
maintain daily and on a regular schedule
before the instrument gets seriously dull
92
impression material that is mixed to a sol state, as it sets converts to a gel by a chemical reaction that irreversible
alginate(irreversible hydrocolloid)
agar(reversible hydrocolloid)
93
strength that is measured when the excess water is not present in the sample.
wet strength
dry strength
