Operative Flashcards
1
Q
Which of the following statements regarding
caries risk assessment is correct?
A. The presence of restorations is a good indicator of
current caries activity.
B. The presence of restorations is a good indicator of
past caries activity.
C. The presence of dental plaque is a good indicator
of current caries activity.
D. The presence of pit-and-fissure sealants is a good
indicator of current caries activity.
A
B. A restored tooth indicates potential past carious
activity but not current activity. Plaque presence
does not necessarily indicate caries presence
and sealants are used for preventive purposes,
not caries treatment
2
Q
Which of the following statements about indirect
pulp caps is false?
A. Some leathery caries may be left in the
preparation.
B. A liner is generally recommended in the
excavation.
C. The operator should wait at least 6 to 8 weeks
before re-entry (if then).
D. The prognosis of indirect pulp cap treatment is
poorer than that of direct pulp caps.
A
D. When doing an indirect pulp cap some caries
may be left, a liner [probably Ca(OH)2] is usually
placed over the excavated area, and the area
may be assessed 6 to 8 weeks later. Regardless,
the indirect pulp cap prognosis is better than the
prognosis for direct pulp caps
3
Q
Smooth surface caries refers to \_\_\_\_\_. A. Facial and lingual surfaces. B. Occlusal pits and grooves. C. Mesial and distal surfaces. D. A and C.
A
. D. Smooth surface caries occurs on any of the axial
(facial, lingual, mesial, and distal) tooth surfaces
but not the occlusal.
4
Q
The use of the rubber dam is best indicated for \_\_\_\_\_. A. Adhesive procedures. B. Quadrant dentistry. C. Teeth with challenging preparations. D. Difficult patients. E. All of the above.
A
. E. The advantages and benefits of rubber dam
usage are reflected in all of the items stated. The
rubber dam isolation increases access and visibility.
5
Q
For a dental hand instrument with a formula of
10-8.5-8-14, the number 10 refers to _____.
A. The width of the blade in tenths of a millimeter.
B. The primary cutting edge angle in centigrades.
C. The blade length in millimeters.
D. The blade angle in centigrades.
A
A. The first number is the width of the blade or primary
cutting edge in tenths of a millimeter (0.1
mm). The second number of a four-number
code indicates the primary cutting edge angle,
measured from a line parallel to the long axis of
the instrument handle in clockwise centigrades.
The angle is expressed as a percent of 360
degrees. The instrument is positioned so that this
number always exceeds 50. If the edge is locally
perpendicular to the blade, then this number is
normally omitted, resulting in a three-number
code. The third number (second number of a
three-number code) indicates the blade length in
millimeters. The fourth number (third number of
a three-number code) indicates the blade angle,
relative to the long axis of the handle in clockwise
centigrades
6
Q
When placement of proximal retention locks in
Class II amalgam preparations is necessary,
which of the following is incorrect?
A. One should not undermine the proximal enamel.
B. One should not prepare locks entirely in axial
wall.
C. Even if deeper than ideal, one should use the
axial wall as a guide for proximal lock placement.
D. One should place locks 0.2 mm inside the DEJ to
ensure that the proximal enamel is not
undermined.
A
C. Retention locks, when needed in Class II amalgam
preparations, should be placed entirely in
dentin, thereby not undermining the adjacent
enamel. They are placed 0.2 mm internal to theDEJ, are deeper gingivally (0.4 mm) than
occlusally (i.e., they fade out as they extend
occlusally, and translate parallel to the DEJ). If
the axial wall is deeper than normal, the retention
lock is not placed at the axiofacial or axiolingual
line angles but, rather, is positioned 0.2 mm
internal to the DEJ. If placed at the deeper location,
it may result in pulp exposure, depending on
the location of the axial wall depth.
7
Q
Choose the incorrect statement about Class V
amalgam restorations.
A. The outline form is usually kidney- or crescent-
shaped.
B. Because the mesial, distal, gingival, and incisal
walls of the tooth preparation are perpendicular
to the external tooth surface, they usually diverge
facially.
C. Using four corner coves instead of two full-length
grooves conserves dentin near the pulp and may
reduce the possibility of a mechanical pulp
exposure.
D. If the outline form approaches an existing
proximal restoration, it is better to leave a thin
section of tooth structure between the two
restorations (< 1 mm) than to join the
restorations.
A
D. Because of the typical shape of a carious lesion
in the cervical area, the resulting restoration is
kidney- or crescent-shaped and the extensions
are to the line angles, resulting in the mesial and
distal walls diverging externally. The convexity of
the tooth in the gingival one third results in the
occlusal and gingival walls diverging externally.
There are several retention groove designs that
are appropriate, including four corner coves,
occlusal and gingival line angle grooves, or circumferential
grooves. However, as with any
restoration, if there is only a small amount of
tooth structure (< 1 mm) between the new and
existing restoration, it is best to join the two
restorations together and prevent the possibility
of fracture of the small amount of remaining
tooth structure.
8
Q
In the conventional Class I composite preparation, retention is achieved by which of the following features? 1. Occlusal convergence 2. Occlusal bevel 3. Bonding 4. Retention grooves A. 2 and 4 B. 1 and 3 C. 1 and 4 D. 2 and 3
A
B. Typically, the Class I composite preparation has
occlusally converging walls that provide primary
retention form. The actual bonding also provides
retention form. However, an occlusal bevel is not
indicated on Class I preparations nor are retention
grooves used
9
Q
Many factors affect tooth/cavity preparation.
Which of the following would be the least
important factor?
A. Extent of the defect.
B. Size of the tooth.
C. Fracture lines.
D. Extent of the old material.
A
B. Obviously, a tooth preparation is dictated by the
extent of the carious lesion or old restorative
material, the creation of appropriate convenience
form for access and vision, and the anticipated
extensions necessary to provide an
appropriate proximal contact relationship.
Fracture lines present should normally be
377
Answer Key for Section 2
included in the restoration. However, it is rare
that the size of the tooth will affect the design of
the tooth preparation
10
Q
- Which of the following statements about an
amalgam tooth/cavity preparation is true?
A. The enamel cavosurface margin angle must be 90
degrees.
B. The cavosurface margin should provide for a 90-
degree amalgam margin.
C. All prepared walls should converge externally.
D. Retention form for Class Vs can be placed at the
DEJ.
A
- B. Although the amalgam margin must be 90
degrees, the enamel margin may not be 90
degrees, especially on the occlusal surface. Most
walls converge occlusally, but many Class V
amalgam preparations have walls that diverge
externally. No retention form should be placed at
the DEJ; otherwise, the adjacent enamel will be
undermined and subject to fracture
11
Q
Causes of postoperative sensitivity with amalgam restorations include all of the following except \_\_\_\_\_. A. Lack of adequate condensation, especially lateral condensation in the proximal boxes. B. Voids. C. Extension onto the root surface. D. Lack of dentinal sealing.
A
C. The primary causes of postoperative sensitivity
for amalgam restorations are voids (especially at
the margins), poor condensation (that may result
in a void), or inadequate dentinal sealing.
Extension onto the root surface does not necessarily
result in increased sensitivity
12
Q
When carving a Class I amalgam restoration,
which statement is false?
A. Carving may be made easier by waiting 1 or 2
minutes after condensation before it is started.
B. The blade of the discoid carver should move
parallel to the margins resting totally on the
partially set amalgam.
C. Do not carve deep occlusal anatomy.
D. The carved amalgam outline should coincide with
the cavosurface margins.
A
. B. Amalgam carving should result in coincidence
with the cavosurface margin and should not
result in deep occlusal anatomy because such
form may create acute amalgam angles that are
subject to fracture. Depending on the condensation
rate of the amalgam used, waiting a couple
of minutes prior to initiating carving may allow
the amalgam to harden enough that the carving
will be easier and overcarving will be minimized.
When carving the occlusal cavosurface margin,
the discoid carver should rest on the adjacent
unprepared enamel, which will serve as a guide
for proper removal of amalgam back to the
margin.
13
Q
The setting reaction of dental amalgam proceeds
primarily by _____.
A. Dissolution of the entire alloy particle into
mercury.
B. Dissolution of the Cu from the particles into
mercury.
C. Precipitation of Sn-Hg crystals.
D. Mercury reaction with Ag on or in the alloy
particle.
A
D. The trituration process mixes the amalgam components
and the reaction results in the alloy
particle being coated by mercury and a product
being formed.
14
Q
Restoration of an appropriate proximal contact
results in all of the following except _____.
A. Reduction/elimination of food impaction at the
interdental papilla.
B. Provide appropriate space for the interdental
papilla.
C. Provide increased retention form for the
restoration.
D. Maintenance of the proper occlusal relationship.
A
C. Proper proximal contacts reduce the potential
for food impaction, thereby preserving the
health of the underlying soft tissue. A missing
proximal contact may result in tooth movement
that will have an adverse effect on the occlusal
relationship of the tooth. Having a correct contact
does not enhance the retentive properties of
the restorative material.
15
Q
A major difference between total-etch and self-
etching primer dentin bonding systems include
all of the following except \_\_\_\_\_. A. The time necessary to apply the material(s). B. The amount of smear layer removed. C. The bond strengths to enamel. D. The need for wet bonding.
A
A. Self-etch dentin bonding systems differ from
total-etch dentin bonding systems by removing
less of the smear layer (they use a less potent
acid), creating a weaker bond to enamel (especially
nonprepared enamel), and not requiring
wet bonding that may be necessary for some of
the total-etch systems. Even though fewer
actual materials may be needed with some of
the self-etch systems, they need to be applied
in multiple coats and thus the time necessary
to apply the materials is similar for both
systems.
16
Q
A casting may fail to seat on the prepared tooth
due to all of the following factors except _____.
A. Temporary cement still on the prepared tooth
after the temporary restoration has been
removed.
B. Proximal contact(s) of casting too heavy/tight.
C. Undercuts present in prepared tooth.
D. The occlusal of the prepared tooth was under-
reduced.
A
D. Occlusal reduction would not affect the ability
to seat a casting. However, temporary cement,
heavy proximal contacts, or tooth undercuts
could keep the casting from seating completely
17
Q
All of the following reasons are likely to indicate
the need for restoration of a cervical notch
except _____.
A. Patient age.
B. Esthetic concern.
C. Tooth is symptomatic.
D. Deeply notched axially.
A
A. If a patient has a notched cervical area that is
very sensitive or very esthetically objectionable,
restoration is usually indicated. If the notched
area is very deep, adverse pulpal or gingival
responses may occur. Although more notched
areas are encountered in older patients, a
patient’s age is not a factor in the need for
restoration
18
Q
All of the following statements about slot-
retained complex amalgams are true
except _____.
A. Slots should be 1.5 mm in depth.
B. Slots should be 1 mm or more in length.
C. Slots may be segmented or continuous.
D. Slots should be placed at least 0.5 mm inside the
DEJ.
A
A. The longer a slot, the better. They should be
inside the DEJ and prepared with an inverted
cone bur to a depth of 1 mm
19
Q
Which one of the following acids is generally
recommended for etching tooth structure?
A. Maleic acid
B. Polyacrylic acid
C. Phosphoric acid
D. Tartaric acid
E. Ethylenediaminetetraacetic acid (EDTA)
A
C. Although some of the self-etch bonding systems
use milder acid, the primary acid system used for
etching tooth structure is phosphoric acid.
20
Q
Triturating a dental amalgam will _____.
A. Reduce the size of the alloy particles.
B. Coat the alloy particles with mercury.
C. Reduce the crystal sizes as they form.
D. Dissolve the alloy particles in mercury.
A
B. Triturating (mixing) the amalgam particle with
the mercury is intended to result in coating the
particles with a surface of mercury and creating
the desirable phases in the set amalgam. All of
the alloy particle is not dissolved in the mercury,
nor is the size significantly reduced.
21
Q
Which of the following materials has the highest linear coefficient of expansion? A. Amalgam B. Direct gold C. Tooth structure D. Composite resin
A
D. Composite materials exhibit more dimensional
change (2.5 times greater than tooth structure)
when subjected to extreme changes in temperature
than do the other choices. Direct gold is
slightly higher than tooth structure, and amalgam
is about twice as high as tooth structure.
22
Q
A cervical lesion should be restored if it is \_\_\_\_\_. A. Carious. B. Very sensitive. C. Causing gingival inflammation. D. All of the above.
A
. D. All of these factors indicate that a cervical lesion
should be restored. In addition, if the lesion is large
and the pulpal or gingival tissues are in jeopardy, it
should be considered for restoration
23
Q
In comparison to amalgam restoration, composite restorations are \_\_\_\_\_. A. Stronger. B. More technique-sensitive. C. More resistant to occlusal forces. D. Not indicated for Class II restorations.
A
B. Composite restorations are more techniquesensitive
than amalgam restorations because the
bonding process is very specific (requiring
exact, correct usage of the various materials and
an isolated, noncontaminated field), and the
insertion and contouring of composites are
more demanding and time-consuming.
Composites are not stronger than amalgam and
have similar wear resistance compared to amalgams.
Composites are indicated for Class II
restorations
24
Q
The one constant contraindication for a
composite restoration is _____.
A. Occlusal factors.
B. Inability to isolate the operating area.
C. Extension onto the root surface.
D. Class I restoration with a high C-factor.
A
B. The constant contraindication for using a composite
restoration is the inability to properly isolate
the operating area. Occlusal wear of
composite is similar to that of amalgam.
Extension onto the root surface may result in gap
formation with composite but also results in
initial leakage with amalgam, indicating that
there is no ideal material for root-surface
extended restorations. A high C-factor (Class I)
can be largely overcome by using (1) a liner
under the composite, (2) a filled adhesive, and
(3) incremental insertion of the composite.
25
Which of the following statements is true
regarding the choice between doing a composite
or amalgam restoration?
A. Establishing restored proximal contacts is easier
with composite.
B. The amalgam is more difficult and technique-
sensitive.
C. The composite generally uses a more
conservative tooth/cavity preparation.
D. Amalgam should be used for Class II restorations.
C. The restoration of a proximal contact is easier
with amalgam than composite. Amalgam is easier
to use and is less technique-sensitive. Either
material can be used for Class II restorations.
Because an amalgam restoration requires a tooth
preparation that has (1) a specified depth(for strength of the amalgam), (2) cavosurface
marginal configurations that result in 90-degree
amalgam margins, and (3) undercut form to its
walls or secondary retention form features, they
require more tooth structure removal than do
composite tooth preparations. Composite tooth
preparations require (1) removal of the fault,
defect, or old material; (2) removal of friable
tooth structure; and (3) no specific depths—they
are more conservative.
26
```
A good preventive and treatment strategy for
dental caries would include _____.
A. Limiting cariogenic substrate
B. Controlling cariogenic flora
C. Elevating host resistance
D. All of the above
```
D. Altering the organism, its nutrients, and its
environment will all enhance prevention and treatment
objectives.
27
Which of the following statements regarding
caries risk assessment is correct?
A. The presence of restorations is a good indicator
of current caries activity.
B. The presence of restorations is a good indicator
of past caries activity.
C. The presence of dental plaque is a good
indicator of current caries activity.
D. The presence of pit-and-fissure sealants is a
good indicator of current caries activity.
B. A restored tooth indicates potential past carious
activity but not current activity. Plaque presence
does not necessarily indicate caries presence
and sealants are used for preventive purposes,
not caries treatment.
28
```
Which of the following is considered a
reversible carious lesion?
A. The lesion surface is cavitated.
B. The lesion has advanced to the dentin
radiographically.
C. A white spot is detected upon drying.
D. The lesion surface is rough or chalky.
```
C. When an alteration (a break in continuity) occurs
to the tooth surface from a carious attack, restoration
is usually necessary. When a lesion is evident
in the dentin with an x-ray, the lesion usually needs
a restoration
29
Which of the following statements about indi-
rect pulp caps is false?
A. Some leathery caries may be left in the
preparation.
B. A liner is generally recommended in the
excavation.
C. The operator should wait at least 6 to 8 weeks
before re-entry (if then).
D. The prognosis of indirect pulp cap treatment is
poorer than that of direct pulp caps.
D. When doing an indirect pulp cap, some caries
may be left, a liner (probably Ca[OH]2
) is usually
placed over the excavated area, and the area may
be assessed 6 to 8 weeks later. Regardless, the
indirect pulp cap prognosis is better than the
prognosis for direct pulp caps.
30
```
Smooth surface caries refers to _____.
A. Facial and lingual surfaces
B. Occlusal pits and grooves
C. Mesial and distal surfaces
D. Both A and C.
```
D. Smooth surface caries occurs on any of the axial
(facial, lingual, mesial, and distal) tooth surfaces
but not the occlusal.
31
A finishing bur has how many blades com-
pared to a cutting bur?
A. Fewer blades.
B. Same number of blades.
C. More blades.
D. Number of blades is unrelated to the bur type.
C. A finishing bur is designed to provide a smoother
surface and therefore has more blades than a
cutting bur. The increased blade numbers results
in a smoother cut surface.
32
```
The use of the rubber dam is best indicated for
_____.
A. Adhesive procedures
B. Quadrant dentistry
C. Teeth with challenging preparations
D. Difficult patients
E. All of the above
```
E. The advantages and benefits of rubber dam
usage are reflected in all of the items stated. The
rubber dam isolation increases access and
visibility
33
The reason to invert a rubber dam is _____.
A. To prevent the dam from tearing
B. To prevent the underlying gingival from
accidental trauma
C. To provide a complete seal around the teeth
D. All of above
. C. When the rubber dam edge around the tooth is
turned gingivally (inverted), it significantly
reduces the leakage of moisture occlusally,
thereby sealing around the tooth better and
resulting in a better isolated operating area
34
For a dental hand instrument with a formula
of 10-8.5-8, the number 10 refers to _____.
A. The width of the blade, in tenths of a millimeter
B. The primary cutting edge angle, in centigrades
C. The blade length, in millimeters
D. The blade angle, in centigrades
A. The first number is the width of the blade or
primary cutting edge in tenths of a millimeter(0.1 mm). The second number of a four-number
code indicates the primary cutting edge angle,
measured from a line parallel to the long axis of
the instrument handle in clockwise centigrades.
The angle is expressed as a percent of 360
degrees. The instrument is positioned so that
this number always exceeds 50. If the edge is
locally perpendicular to the blade, then this
number is normally omitted, resulting in a threenumber
code. The third number (second
number of a three-number code) indicates the
blade length in millimeters. The fourth number
(third number of a three-number code) indicates
the blade angle, relative to the long axis of the
handle in clockwise centigrade.
35
The tooth preparation technique for a Class I
amalgam on a mandibular first molar does not
include which of the following?
A. Maintaining a narrow isthmus width
B. Initial punch cut placed in the most carious pit
C. Establishment of pulpal depth of 1.5 to 2 mm
D. Orientation of bur parallel to the long axis of the
tooth
D. A tooth preparation for a mandibular molar
should have a narrow isthmus, should be initiated
in the most carious (or distal) pit, and
should establish the initial pulpal floor depth of
1.5 to 2 mm. However, it should be oriented
parallel to the long axis of the crown, which tilts
to the lingual. If prepared in the long axis of the
tooth, there is greater potential of weakening
the lingual cusps.
36
When placement of proximal retention locks in
Class II amalgam preparations is necessary,
which of the following is incorrect?
A. One should not undermine the proximal enamel.
B. One should not prepare locks entirely in the
axial wall.
C. Even if deeper than ideal, one should use the
axial wall as a guide for proximal lock
placement.
D. One should place locks 0.2 mm inside the DEJ
to ensure that the proximal enamel is not
undermined.
C. Retention locks, when needed in Class II amalgam
preparations, should be placed entirely in
dentin, thereby not undermining the adjacent
enamel. They are placed 0.2 mm internal to the
DEJ, are deeper gingivally (0.4 mm) than
occlusally (i.e., they fade out as they extend
occlusally), and translate parallel to the DEJ. If
the axial wall is deeper than normal, the retention
lock is not placed at the axiofacial or axiolingual
line angles but, rather, is positioned 0.2 mm
internal to the DEJ. If placed at the deeper location,
it may result in pulp exposure, depending on
the location of the axial wall depth.
37
When the gingival margin is gingival to the CEJ in
a Class II amalgam preparation, the axial depth
of the axiogingival line angle should be _____.
A. 0.2 mm into sound dentin
B. Twice the diameter of a No. 245 carbide bur
C. 0.75 to 0.80 mm
D. The width of the cutting edge of a gingival
marginal trimmer
C. The guide for axial wall depth for a typical Class
II preparation that has a gingival margin occlusal
to the CEJ is 0.2 to 0.5 mm internal to the DEJ—
the greater depth is necessary when placing
retention locks. However, when there is no
enamel proximally, the axial wall needs to be
deep enough internally to provide for adequate
strength of the amalgam material as well as to
have room to place retention locks, if needed.
This depth is approximately 0.75 mm.
38
Choose the incorrect statement about Class V
amalgam restorations.
A. The outline form is usually kidney- or crescent-
shaped.
B. Because the mesial, distal, gingival, and incisal
walls of the tooth preparation are perpendicular
to the external tooth surface, they usually
diverge facially.
C. Using four corner coves instead of two full-
length grooves conserves dentin near the pulp
and may reduce the possibility of a mechanical
pulp exposure.
D. If the outline form approaches an existing
proximal restoration, it is better to leave a thin
section of tooth structure between the two
restorations (< 1 mm) than to join the
restorations.
. D. Because of the typical shape of a carious lesion in
the cervical area, the resulting restoration is
kidney- or crescent-shaped and the extensions
are to the line angles, resulting in the mesial and
distal walls diverging externally. The convexity of
the tooth in the gingival one-third results in the
occlusal and gingival walls diverging externally.
There are several retention groove designs that
are appropriate, including four corner coves,
occlusal and gingival line angle grooves, or circumferential
grooves. However, as with any
restoration, if there is only a small amount of tooth
structure (< 1 mm) between the new and existing restoration, it is best to join the two
restorations together and prevent the possibility of
fracture of the small amount of remaining
tooth structure
39
When preparing a Class III or IV composite
tooth preparation, which of the following is
false regarding placement of retention form?
A. Often involves gingival and incisal retention
B. Is placed at the axiogingival line angle
regardless of the depth of the axial wall
C. May be needed in large preps
D. Is usually prepared with a No. 1/4 round bur
B. When needed for large restorations, retention
form usually consists of a gingival groove and
incisal cove prepared with a small round bur (No.
1/4). The placement of the groove or cove is
dependent on the DEJ, placing the retention 0.2
mm internal to the DEJ entirely in dentin. It is not
placed at the axiogingival or axioincisal line
angles if those line angles are deeper than ideal;
otherwise, the retention form may be too deep or
cause a pulpal exposure
40
In the conventional Class I composite prepara-
tion, retention is achieved by which of the
```
following features?
1. Occlusal convergence
2. Occlusal bevel
3. Bonding
4. Retention grooves
A. 2 and 4
B. 1 and 3
C. 1 and 4
D. 2 and 3
```
B. Typically, the Class I composite preparation has
occlusally converging walls that provide primary
retention form. The actual bonding also provides
retention form. However, an occlusal bevel is not
indicated on Class I preparations, nor are retention
grooves utilized
41
The success of an amalgam restoration is
dependent on all of the following features of
tooth/cavity preparation except _____.
A. Butt-joint cavosurface margin that results in a
90-degree margin for the amalgam
B. Adequate tooth removal for appropriate strength
of the amalgam
C. Divergent (externally) preparation walls
D. Adequate retention form features to mechanically
lock the amalgam in the preparation
C. A successful amalgam restoration requires
90-degree amalgam margins. Amalgam margins
less than 90 degrees result in increased potential
for fracture of the amalgam. Greater than
90-degree amalgam margins are good for the
amalgam but the corresponding enamel margin
will be less than 90 degrees and therefore potentially
undermined and have potential for fracture.
Since the amalgam is not bonded to the tooth, it
must be retained in the tooth with undercuts,
either in the primary or secondary preparation. An
amalgam restoration needs a minimum of
1-mm thickness in nonstress areas and 1.5 to 2
mm in areas that may be under load. Therefore,
the preparation must provide this dimension.
Except for Class V amalgams, the prepared walls
generally converge to the exterior. Thus, the prepared
walls may diverge or converge externally
42
Many factor affect tooth/cavity preparation.
Which of the following would be the least
important factor?
A. Extent of the defect
B. Size of the tooth
C. Fracture lines
D. Extent of the old material
B. Obviously, a tooth preparation is dictated by the
extent of the carious lesion or old restorative
material, the creation of appropriate convenience
form for access and vision, and the anticipated
extensions necessary to provide an
appropriate proximal contact relationship.
Fracture lines present should normally be
included the restoration. However, it is rare that
the size of the tooth will affect the design of the
tooth preparation
43
Which of the following statements about an
amalgam tooth/cavity preparation is true?
A. The enamel cavosurface margin angle must be
90 degrees.
B. The cavosurface margin should provide for a
90-degree amalgam margin.
C. All prepared walls should converge externally.
D. Retention form for Class Vs can be placed at the
DEJ.
. B. Although the amalgam margin must be
90 degrees, the enamel margin might not be 90
degrees, especially on the occlusal surface. Most
walls converge occlusally, but many Class V
amalgam preparations have walls that diverge
externally. No retention form should be placed at
the DEJ; otherwise, the adjacent enamel will be
undermined and subject to fracture.
44
A “skirt” feature for a gold onlay preparation
_____.
A. Has a shoulder gingival margin design
B. Is prepared by a diamond held perpendicular to
the long axis of the crown
C. Is used only for esthetic areas of a tooth
D. Increases both retention and resistance forms
D. A skirt is a “mini-crown” preparation around a line
angle. It should be prepared by a diamond
instrument in the long axis of the tooth crown,
extended to the gingival one-third, and result in an appropriate amount of tooth removal. It is placed
to increase both retention form (having opposing
skirt vertical walls retentive with each other) and
resistance form (enveloping the line angles like a
barrel hoop around a barrel). It extends the outline
form and therefore may be least appropriate for
highly esthetic areas in the mouth
45
Causes of postoperative sensitivity with amal-
gam restorations include all of the following
except _____.
A. Lack of adequate condensation, especially
lateral condensation in the proximal boxes
B. Voids
C. Extension onto the root surface
D. Lack of dentinal sealing
C. The primary causes of postoperative sensitivity for
amalgam restorations are voids (especially at the
margins), poor condensation (that may result
in void), or inadequate dentinal sealing.
Extension onto the root surface does not necessarily
result in increased sensitivity.
46
Factors that affect the success of dentin bond-
ing include all of the following except _____.
A. Dentin factors such as sclerosis, tubule
morphology, and smear layer
B. Tooth factors such as attrition, abrasion, and
abfraction
C. Material factors such as compressive and tensile
strengths
D. C-factor considerations
C. Tensile and compressive strengths may have relevance
for composite materials but not for dentin
bonding systems. The success of bonding is
dependent on the various dentin structural factors,
tooth factors, polymerization shrinkage,
C-factor considerations, and technique sensitivity
47
When carving a Class I amalgam restoration,
which statement is false?
A. Carving may be made easier by waiting 1 or
2 minutes after condensation before it is started.
B. The blade of the discoid carver should move
parallel to the margins resting on the partially set
amalgam.
C. Do not carve deep occlusal anatomy.
D. The carved amalgam outline should coincide
with the cavosurface margins.
B. Amalgam carving should result in coincidence
with the cavosurface margin and should not
result in deep occlusal anatomy because such
form may create acute amalgam angles that are
subject to fracture. Depending on the condensation
rate of the amalgam used, waiting a couple of
minutes prior to initiating carving may allow the
amalgam to harden enough that the carving will
be easier and overcarving will be minimized.
When carving the occlusal cavosurface margin,
the discoid carver should rest on the adjacent
unprepared enamel, which will serve as a guide
for proper removal of amalgam back to the margin
48
It is generally accepted that the maximum
thickness of a composite increment that allows
for proper cure is _____.
A. 1–2 mm.
B. 2–4 mm.
C. 4–6 mm.
D. There is no maximum thickness restriction.
. A. Generally, composite can be properly polymerized
| in 1- to 2-mm increments
49
The setting reaction of dental amalgam pro-
ceeds primarily by _____.
A. Dissolution of the entire alloy particle into
mercury
B. Dissolution of the Cu from the particles into
mercury
C. Precipitation of Sn-Hg crystals
D. Mercury reaction with Ag on or in the alloy
particle
D. The trituration process mixes the amalgam components
and the reaction results in the alloy particle
being coated by mercury and a product
formed.
50
```
What is the half-life of Hg in the human body?
A. 5 days
B. 25 days
C. 55 days
D. 85 days
E. 128 days
```
C. Fifty-five days is the half-life of mercury in the
| body
51
Restoration of an appropriate proximal con-
tact results in all of the following except _____.
A. Reduction/elimination of food impaction at the
interdental papilla
B. Provides appropriate space for the interdental
papilla
C. Provides increased retention form for the
restoration
D. Maintenance of the proper occlusal relationship
C. Proper proximal contacts reduce the potential for
food impaction, thereby preserving the health of
the underlying soft tissue. A missing proximal
contact may result in tooth movement that will
have an adverse effect on the occlusal relationship
of the tooth. Having a correct contact does not
enhance the retentive properties of the restorative
material
52
```
The best way to carve amalgam back to
occlusal cavosurface margin is to _____.
A. Use visual magnification
B. Use a discoid-cleoid instrument guided by the
adjacent unprepared enamel
C. Make deep pits and grooves
D. Use a round finishing bur after the amalgam has
set
```
B. Using the adjacent unprepared enamel at the
cavosurface margin to guide the discoid carving
instrument when carving away excess amalgam
at the occlusal margin is the best way to develop
the junction correctly
53
A major difference between total-etch and self-
etching primer dentin bonding systems include
```
all of the following except _____.
A. The time necessary to apply the material(s)
B. The amount of smear layer removed
C. The bond strengths to enamel
D. The need for wet bonding
```
A. Self-etch dentin bonding systems differ from totaletch
dentin bonding systems by removing less of
the smear layer (they use a less potent acid), creating
a weaker bond to enamel (especially nonprepared
enamel), and not requiring wet bonding
which may be necessary for some of the total-etch systems. Even though fewer actual materials may
be needed with some of the self-etch systems, they
need to be applied in multiple coats and therefore
the time necessary to apply the materials is similar
for both systems
54
Which of the following statements is not true
regarding bonding systems?
A. Even though dentin bonding occurs slowly, it
results in a stronger bond than to enamel.
B. Enamel bonding occurs quickly, is strong, and is
long-lasting.
C. One-bottle dentin bonding systems may be
simpler but are not necessarily better.
D. Dentin bonding is still variable because of
factors such as sclerosis, tubule size, and tubule
location.
A. Dentin bonding in laboratory studies may create
bond strengths similar to or greater than bond
strengths to enamel. However, clinical studies
cannot corroborate that the dentin bond is
stronger. In fact, the bond may deteriorate over
time. Sufficient information is not available to
accurately predict the bond potential to dentin in
every application. Bonding to enamel, however,
is predictable and good. The attempt to simplify
the bonding mechanism has resulted in less
materials being involved and less decision making
on the part of the operator—both in an effort
to get more predictable results. However, the
newer bonding systems have not yet been
proven to be better
55
A casting may fail to seat on the prepared
tooth due to all of the following factors except
_____.
A. Temporary cement still on the prepared tooth
after the temporary restoration has been
removed.
B. Proximal contact(s) of casting are too heavy or
too tight.
C. Undercuts present in prepared tooth.
D. The occlusal of the prepared tooth was under-
reduced.
D. Occlusal reduction would not affect the ability to
seat a casting. However, temporary cement, heavy
proximal contacts, or tooth undercuts could keep
the casting from seating completely
56
For a gold casting alloy, which of the following
is added primarily to act as a scavenger for
oxygen during the casting process?
A. Copper
B. Palladium
C. Silver
D. Zinc
D. Zinc is added to act as a scavenger for oxygen during
the casting process. Copper and palladium
increase the hardness and affect the color. Silver
has an effect on the color as well.
57
All of the following reasons are likely to indi-
cate the need for restoration of a cervical
```
notch except _____.
A. Patient age.
B. Esthetic concern.
C. Tooth is symptomatic.
D. Tooth is deeply notched axially.
```
A. If a patient has a notched cervical area that is very
sensitive or very esthetically objectionable, restoration
is usually indicated. If the notched area is very
deep, adverse pulpal or gingival responses may
occur. Although more notched areas are encountered
in older patients, a patient’s age is not a factor
in the need for restoration
58
When comparing pin retention with slot reten-
tion for a complex amalgam restoration, which
of the following statements is false?
A. Slots are used where vertical walls allow
opposing retention locks.
B. Slots provide stronger retention than pins.
C. Slots and grooves can be used interchangeably.
D. Pin retention is used primarily where there are
few or no vertical walls.
. B. Slots and pins may be used interchangeably.
They both provide good secondary retention form.
Slots are usually better when there exist box forms
or vertical walls in the preparation, and pins are
usually better when there are few or no vertical
walls. The retention is similar for both.
59
All of the following statements about slot-
retained complex amalgams are true except
_____.
A. Slots should be 1.5 mm in depth.
B. Slots should be 1 mm or more in length.
C. Slots may be segmented or continuous.
D. Slots should be placed at least 0.5 mm inside
the DEJ.
A. The longer a slot, the better. They should be
inside the DEJ and prepared with an inverted
cone bur to a depth of 1 mm
60
```
Bonding of resins to dentin is best described as
involving _____.
A. Mechanical interlocking
B. Ionic bonding
C. Covalent bonding
D. Van der Waals forces
```
A. The bond of adhesives to dentin (and enamel) is
primarily a mechanical interlocking of the material
within the dentin (or enamel). The etching causes
some removal of the surface, creating irregularities
or spaced collagen fibrils into which the adhesive
enters. When polymerized, the adhesive is
mechanically locked into the surface
61
```
Which one of the following acids is generally
recommended for etching tooth structure?
A. Maleic acid
B. Polyacrylic acid
C. Phosphoric acid
D. Tartaric acid
E. EDTA
```
C. Although some of the self-etch bonding systems
use milder acid, the primary acid system used for
etching tooth structure is phosphoric acid
62
The principal goals of bonding are _____.
A. Sealing and thermal insulation
B. Strengthening teeth and esthetics
C. Esthetics and reduction of postoperative sensitivity
D. Sealing and retention
E. Retention and reduction of tooth flexure
D. Bonding is primarily for sealing the dentin and
enhancing the retention of the restorative material
in the preparation. Esthetic benefits are a welcome
side benefit when using a composite restoration.
Thermal insulation is provided by the use of
composite as compared to amalgam but is not a benefit of the bonding. Bonding will not alter tooth
flexure under normal load but may better help
bond the unprepared tooth structure together.
63
Triturating a dental amalgam will _____.
A. Reduce the size of the alloy particles
B. Coat the alloy particles with mercury
C. Reduce the crystal sizes as they form
D. Dissolve the alloy particles in mercury
B. Triturating (mixing) the amalgam particle with
the mercury is intended to result in coating the
particles with a surface of mercury and creating
the desirable phases in the set amalgam. All of
the alloy particle is not dissolved in the mercury
and the size is not significantly reduced.
64
The primary contraindication(s) for the use of
a composite restoration is (are) _____.
A. Occlusal factors
B. Inability to isolate the operating area
C. Nonesthetic areas
D. Extension onto the root surface
B. The only constant contraindication for the use of
composite is when the operating area cannot be
properly isolated, thereby decreasing the potential
success of the bond
65
Which of the following materials has the high-
est linear coefficient of expansion?
A. Amalgam
B. Direct gold
C. Tooth structure
D. Composite resin
D. Direct gold and tooth structure have similar linear
coefficients of expansion. Amalgram exhibits
twice that expansion whereas composite
expansion would be even greater (2.5 times
greater than tooth structure)
66
```
The most common pin used in restorative
procedures is a(an) _____.
A. Friction-locked pin
B. Cemented pin
C. Amalgampin
D. Self-threaded pin
```
D. Self-threaded pins are used by most operators,
| when pin use is indicated.
67
```
A cervical lesion should be restored if it _____.
A. Is carious
B. Is very sensitive
C. Is causing gingival inflammation
D. All of the above
```
D. All of these factors indicate a cervical lesion
should be restored. In addition, if the lesion is
large and the pulpal or gingival tissues are in jeopardy,
it should be considered for restoration
68
With regard to the mercury controversy related
to the use of amalgam restorations, which
statement is incorrect?
A. There is lack of scientific evidence that
amalgam poses health risks to humans except
for rare allergic reactions.
B. Alternative amalgam-like materials (with low or
no mercury content) have promise about
mercury.
C. True allergies to amalgam rarely have been
reported.
D. Efforts are underway to reduce the
environmental mercury to which people are
exposed to lessen their total mercury exposure.
B. There are no known alternative low- or nomercury
systems that have been developed
which provide the same properties or clinical
performance as amalgam. The other statements
are true.
69
In comparison to amalgam restorations, com-
posite restorations are _____.
A. Stronger
B. More technique-sensitive
C. More resistant to occlusal forces
D. Not indicated for Class II restorations
B. Composite restorations are more techniquesensitive
than amalgam restorations because the
bonding process is very specific (requiring exact,
correct usage of the various materials and an isolated,
noncontaminated field), and the insertion
and contouring of composites are more demanding
and time-consuming. Composites are not
stronger than amalgam and have similar wear
resistance compared to amalgams. Composites
are indicated for Class II restorations.
70
Which of the following statements is true
regarding the choice between doing a compos-
ite or amalgam restoration?
A. Establishing restored proximal contacts is easier
with composite.
B. The amalgam is more difficult and technique-
sensitive.
C. The composite generally uses a more
conservative tooth/cavity preparation.
D. Only amalgam should be used for Class II
restorations.
C. The restoration of a proximal contact is easier with
amalgam than with composite. Amalgam is easier
to use and is less technique-sensitive. Either material
can be used for Class II restorations. Because an
amalgam restoration requires a tooth preparation
that has (1) a specified depth (for strength of the
amalgam), (2) cavosurface marginal configurations
that result in 90-degree amalgam margins, and (3)
an undercut form to its walls or secondary retention
form features, they require more tooth structure
removal than do composite tooth preparations.
Composite tooth preparations require (1) removal
of the fault, defect, or old material, (2) removal of
friable tooth structure, and (3) no specific depths—
they are more conservative.
71
Ph of enamel demineralization
5.5
72
Best predictor of caries
Past caries history
73
Which is least likely to predict future caries? Amount of sugar intake
Frequency of sugar intake
Amount of caries and restorations
Amount of sugar intake
74
3 factors that affect caries initiation:
substrate, bacteria, host susceptibity
75
Which of the following is the earliest clinical sign of a carious lesion? A. Radiolucency
B. Patient sensitivity
C. Change in enamel opacity
D. Rough surface texture
E.Cavitation of enamel
Change in enamel opacity
76
What is true of Strep. mutans?
• Can live in plaque
• Can live on gingival
• Can live in a child with no teeth
• Has to live on a non-shedding surface
Has to live on a non-shedding surface
77
Most cariogenic sugar
Sucrose
S.mutans adheres to the biofilm on the tooth by converting sucrose into an extremely adhesive substance called dextran
polysaccharide
78
First attachment molecule
Dextran
| Mutans converts sucroseàdextran like long chain polysaccharides (glucans/fructans) using enzyme glucosyltransferase.
79
What helps in carious progression but it is not the primary inititator for caries?
Lactobacillus
80
What is the most important etiologic factor in getting caries?
Saliva pH
Refined sugar
Fluoride tx
saliva flow
Refined sugar
81
Know how to determine if a patient is a high caries risk?
Assessment
82
Early childhood caries affects?
Centrals and molars
83
What one of the following increasing in the US?
Root caries
84
New data regarding caries shows:
a. increase in smooth surf caries - wrong
b. increase in pit/fissure caries - wrong
c. smooth surf caries and pit/fissure caries is same - wrong
d. increase in root caries
increase in root caries
85
QUESTION: Best clinical determinant of root caries?
sensitivity to cold
sensitivity to sweets
soft spot on tooth
soft spot on tooth - visual & tactile methods are used for detect caries
86
Remineralized teeth are stronger than regular enamel. True or False
True
87
For a lesion in enamel that has remineralized, what most likely is true?
1. The enamel has smaller hydroxyapatite crystals than the surrounding enamel
2. The remineralized enamel is softer than the surrounding enamel
3. The remineralized enamel is darker than the surrounding enamel
4. The remineralized enamel is rough and cavitated
3. The remineralized enamel is darker than the surrounding enamel
88
What’s the characteristic of a remineralized tooth/arrested caries?
Darker, harder, more resistant to acid or further decay/caries
89
Characteristic of a lesion that is remineralized:
black, dark, bright
black, dark, opaque
black, dark, cavitated
black, dark, opaque
90
Leathery brown-white lesion? acute, chronic, arrested
arrested
91
What is the most common site of enamel caries?
* pit and fissure
* at the contact point
* slightly incisor to contact
* slightly cervical to contact
• pit and fissure
92
Where does caries start? Apical to proximal contact.
Apical to proximal contact.
93
Most interproximal caries lesion happens where?
Just under/below the contact
94
A class II caries re: contact is
: Apical to contact
95
```
When do you restore a lesion?
When there is cavitation
When it’s half through enamel
When it passes CEJ
When you see it on x-ray
```
When there is cavitation
96
Tx of root surface caries, what kind of dentin should not be restored?
Eburnated dentin (Sclerotic dentin)
97
Smooth surface caries most likely due to?
Plaque
98
Where does fluoride work the best?
A. interproximal
B. Pit and fissure (I saw this somewhere and it said smooth surfaces, pit and fissure is prr/sealant)
C. Smooth surfaces
C. Smooth surfaces
99
Which of the following is a factor for smooth caries & sugar in-take?
Consistency (others were volume, and other option.) I'd think frequency tho
- Sticky consistency stays on the tooth longer, allowing bacteria to keep the pH lower longer
100
For occlusal caries, where is base & cone?
Triangle point is at enamel and base to dentin, dentin base to tip at pulp. (apex to the
pulp)
prolly bc tubules wider towards CEJ
101
What tooth is most likely to have occlusal caries?
Mandibular molar
102
Caries in children depend most on
amount, consistency, & time.
103
Pit and Fissure caries is described as two cones:
a. Two bases are pointing toward the pulp
b. Two apexes are pointing toward pulp>>>> in smooth surface (proximal caries)
c. One apex toward the pulp and one base toward DEJ
d. base of both triangles facing the DEJ
d. base of both triangles facing the DEJ
104
At the DEJ, diff btw smooth, occlusal, and interproximal caries pattern
smooth is conical
occlusal - apex at occlusal
interprox - apex at DEJ
105
Conical shaped caries w/ broad base with apex towards pulp is commonly seen in?
a. root caries
b. smooth caries
c. pit/fissure caries
b. smooth caries
106
Most likely dx indicator of pit and fissure caries is what?
Explorer catch
107
40 y pt w/ all 32 teeth. No cavities. Has stain & catch in pit of molar. what do you do?
a. Watch & observe
b. sealant
c. composite
a. Watch & observe
108
If a dentist seals a caries lesion on the tooth, what would be the most likely result?
1. Arrest caries
2. Extension caries
3. Discoloration of tooth
4. Micro-leakage
1. Arrest caries
109
Radiographic decay most closely resemble which zone of carious enamel? Body zone, dark zone, translucent zone, surface zone
Body zone,
110
When looking at a radiograph, what zone of caries are you looking at?
Body zone Demineralization
111
If you feed a person through a tube, what happens to risk of caries
decreases
112
Mechanism of caries indicator:
indicator: enters the dentin & binds to the denatured collagen.
- A colored dye in an organic base adheres to the denatured collagen, which distinguishes between infected dentin & affected dentin
113
caries indicator only stains
infected dentin
114
What type of caries detection is the Difoti used for?
Class I Class II, Class III (detection of incipient, frank and recurrent caries)
demineralization
115
Diagnodent for which class of caries
Class I pit and fissure occlusal ONLY
116
Sensitivity theory –
hydrodynamic theory
117
Most commonly accepted theory of dentin sensitivity?
Hydrodynamic theory
- Postulates that the pain results from indirect innervation caused by dentinal fluid movement in the tubule that stimulates
mechanoreceptors near the predentin
118
DMFS stands for
decay missing filled surfaces (and includes third molars)
119
DMF index measures
how permanent dentition is affected by caries
120
DMFT measures
amount of tooth decay
121
DMFT is for ____________teeth
permanent (not third molars, not primary teeth)
122
Which race has a higher F in DMFT index?
White
123
Which ethiticity has most caries in kid population (highest caries incidence)?
Hispanics
124
Which population has the most number of UNRESTORED caries?
Blacks
125
Which of the following acronyms is only used for kids? PI, DEFT, DMF, OHI-S, etc
DEFT
126
Differences between 245 and 330 burs:
All other dimensions the same except for
length. Other options were shape, what angle they form.
- 245 bur is 3mm in length while 330 is 1.5mm.
127
Which bur do you use for peds? A.245 bur B.18 C.51
A.245
128
Which is best for occlusal convergence in a prep?
245 (169 is better for facial and lingual)
129
Diameter of 245 bur?
0.8 mm
130
What bur use for amalagam retention in class II? 245 or 330
245
131
Example of pear shape bur: 329, 330, 245 (330L)
- 245 = 330L = pear and elongated bur (tip is a cone)
132
Bur used that converges F and L walls? #245, 7901, 169
169 (tapered bur, 0.9 diameter)
| - If 169 is not there, pick 245.
133
What bur do you use to shape convergent walls for amalgam
à 169
134
```
Burs for smoothing out preps?
More flutes and shallow
more flutes and deeper
less flutes and shallow
less flutes and deeper
```
More flutes and shallow
135
More # of blades on carbide burs --> what?
: SMOOTHER, DECREASED CUTTING EFFICIENCY
136
Which high speed bur gives a smoother surface?
Plain cut fissure bur = best cross cut fissure have a higher cutting efficiency
137
Bur used for polishing –
Carbide have more threads, STEEL FOR POLISH
138
What is the correct method of excavation of deep caries?
a. Large bur from periphery to the center
b. Large bur from center to periphery
c. Small bur from periphery to center
d. Small bur from center to the periphery
a. Large bur from periphery to the center
| use the largest bur that fits, and go around the periphery and then towards the deepest
139
Rotary high speed, how many round per min?
200,000 RPM
| - slowspeed goes 20-30k average, endo = usually 800
140
Chisel vs spoon application:
Chisels are intended primarily to cut enamels, but spoons remove caries & carve amalgams
141
What’s the difference between an enamel hatchet & gingival marginal trimmer?
Both chisels but GMT has curved blade and angled
| cutting edge while Enamel HA has cutting edge in plane of handle
142
Main difference and advantage of using GMT instead of Enamel hatchet?
a. bi-angled cutting surface
b. angle of the blade
c. push/pull action instead of
b. angle of the blade
143
What do you not use to bevel an inlay prep?
a. enamel hatchet
b. ging marg trimmer
c. flame diamond bur
d. carbide bur
a. enamel hatchet
144
What do u not use when beveling gingival margins?
Tapered diamond
| - Causes enamel fracture
145
QUESTION: How do you bevel occlusal floor (gave list of instruments)
• 13, 8
• 15, 80
• 15, 95
• 15, 80 (GMT)
146
What instrument would not be used to bevel the gingival margin of an MOD prep?
Enamel Hatchet
147
Proper pulpal floor depth using Bur 245?
3mm, so half of it is 1.5 mm which is proper pulpal floor depth
148
You did a prep with high speed + diamond bur and tooth is sensitive, what is it about bur and handpiece that it caused sensitivity?
A) Desiccation
B) Traumatized dentin
C) Heat
C) Heat
149
Most common pulpal damage from cavity prep – heat, dentin dessication
heat
150
```
What would cause displacement of odontoblastic processes?
Thermal
Dessication
Mechanical
Chemical
```
Thermal
151
What causes displacement of odontoblastic nuclei in the dental tubules? Thermal, mechanical, chemical, caries, dessication
Thermal
152
Pins in Amalgam:
Pins should be 2mm into dentin, 2mm within amalgam, and 1 mm from the DEJ (to be safe) with no bends in the pins.
153
Resistance for amalgam
1st = Flat floors, rounded angles (bevel in axiopulpal line angles)
154
retention for amalgam
1st = BL walls converge, 2nd = retention grooves/Occlusal dovetail
155
Acute mercury toxicity for dentists or subacute mercury poisoning symptoms, the first signs is:
nausea, other are muscle weakness
| (hypotonia) and hair loss.
156
Most likely for amalgam to fail? Outline cavity design, poor condensation
Outline cavity design,
157
MOD amalgam with hole why?
poor condensation
| - condensation removes mercury (gamma mercury removed)
158
Most common reason for Amalgam fracture occuring in a primary tooth:
Inadequate cavity prep (especially the isthmus area)
159
```
Most common reason for failed amalgam
moisture contamination
improper prep design
improper titrutration
improper condensation
```
improper prep design - not enough depth
- most likely depth (first), then outline form
160
Patient had occlusal amalgam on tooth #30 few weeks ago, one day the dude went to Chinatown and was having lunch with his
hommies. He bit down on something and the amalgam broke off. He came back to your office demanding how could this happen with a new
filling. What should be crossing your mind?
The prep was not deep enough.
161
Ideal cavo margin (margin between tooth and your prep) for amalgam
is 90 degree
162
Axial pulp should be?
0.2 - 0.5 into DEJ
163
How far do you extend the pulpal floor in class I amalgam cavity on primary dentition?
- 1mm into dentin
- Just into dentin
Just into dentin
| (total prep should 1.5 mm so 1 mm for enamel & ~ 0.5 mm for dentin
164
Greatest wear on enamel of the opposing tooth: amalgam, porcelain, microfill, hybrid composite, Porcelain (zirconia)
Porcelain (zirconia)
165
Picture of a deep amalgam w/ overhang: What is wrong with marginal ridge of DO amalgam of #29? All of the following except ?
Occlusal wear, over carving, wedge not placed right,
OVERCARVED
166
Which tooth will the matrix band be a problem with when placing a two surface amalgam?
to give an idea of the anatomy of the region:
mesial on maxillary first molar b/c of the cusp of carabelli also
- mesial Of max 1st premolar (MOST DIFFICULT due to mesialdevelopmental grove, contact is harder) > Distal of max molar
167
```
How to account for mesial concavity on maxillary 1st premolar when restoring with amalgam:
custom wedge
acrylic within matrix
normal matrix
create overhang and recontour
```
custom wedge
168
Two class III lesions adjacent to each other (kissing lesion). Which one do you prep first & which will be filled first?
Prep larger 1st
,
Restore smaller 1st
169
More corrosion of amalgam is in which phase?
Tin-mercury phase (gamma 2 phase)
- Noble metals (gold, pd, platinum) are CORROSION RESISTANT while silver & tin erode
- most common corrosion products found with conventional amalgam alloys are oxides and chlorides of tin
- silver tarnish but copper & tin corrode
170
most common corrosion products in conventional amalgam
oxides and chlorides of tin
171
Zinc in amalgam, what is used for?
Decreases oxidation of other elements (deoxidizer)
- Zinc acts as a deoxidizer, which is an O2 scavenger that minimizes the oxides formation of other elements in the amalgam alloys during
melting.
172
What type of Mercury is in the dental office? Inorganic, elemental
elemental
173
For amalgam, the most toxic mercury is: Elemental mercery, ethyl mercury, methyl mercury
methyl mercury (organic mercury)
174
Type of mercury most hazardous to dentist health: methyl mercury, ethylmercury, inorganic mercury, elemental mercury
methyl mercury,
175
Amalgam large condenser with lateral condensation is used in what type of amalgam
Spherical
176
What type of amalgam needs to be condensed more?
Spherical
177
Material to use for best interproximal contact of a CLASS II is Admix Amalgam , Spherical amalg., Composite w/ filler, Composite w/o
filler
Admix Amalgam
| Admix materials = better for proximals contcts b/c of higher condensation forces
178
From pt images, which amalgam filling has the lowest Copper content?
One that looks corroded.
179
Overtriturating amalgam?
sets too fast, decreases setting expansion, increase compressive strength
180
Huge MOD in posterior à restore with
amalgam
181
Placing pin in amalgam restoration, Amt in tooth/restoration/angulation =
= 2mm
- The optimal depth of the pinhole into dentin is 2mm.
- Threaded pins used in a dental amalgam restoration should be placed 2mm in depth at a position axial to the DEJ & parallel to the
external surface between the pulp and tooth surface.
182
What is wrong about retention pin? Better retention with bigger pin, follows axial, 0.5mm in DEJ.
Better retention with bigger pin,
183
What happens to amalgam if it is contaminated with water/moisture?
Decrease in strength
184
If there is water while you are condensing amalgam, what happens? Delayed expansion , severe expansion,
corrosion, decreased compressive strength
Delayed expansion
185
What happen to amalgam with moisture contamination?
Delayed expansion
186
What is true of amalgam within a year after placement
Marginal leakage increases as restoration ages
Marginal leakage decreases as restoration ages
No marginal leakage
Marginal leakage decreases as restoration ages
| b/c it gets filled with corrosion products
187
You have an amalgam that is deficient at the margin by 0.5mm (concavity) and no signs of recurrent decay. What do you do:
observe/monitor, remove and replace, repair with amalgam
observe/monitor,
188
Where is it acceptable to leave unsupported enamel?
```
Occlusal wall of class V amalgam
- It’s not a bearing surface so you can leave unsupported enamel in class V
```
189
What do class I & class V amalgam ideal prep have in common?
a. both slightly extend into dentin
b. both have flat axial & pulpal wall
a. both slightly extend into dentin
190
What is the reason you would do MOD onlay vs an Amalgam:
Better facial contour (more ideal contours) & less Microleakage
- cusp protection (onlay) vs amalgam
191
Advantage of inlay over amalgam?
Esthetics, less tooth reduction
192
Is the isthmus the same for inlay and amalgam
NO
| - isthmus is convergent for amalgam & divergent for inlay.
193
Resistance form for amalgam prep:
bevel in the axiopulpal line angle to reduce stress and increase RESISTANCE form.
- resistance = keeping the restoration from fracturing, “ways to resist stress”
- smooth floor & line angles. Flat walls are right angles of tooth’s long axis.
194
What’s the best way to prevent proximal dislodgement/fracture of class II amalgam filling?
* Retentive grooves (for proximal resistance)
* converging axial walls (B&L walls)
* depth of prep
195
```
Proximal retention in class II box for amalgam? Retentive grooves, convergence of facial lingual walls, bevel on axiopulpal line
angle, all of the above, none of the above
```
Retentive grooves
196
BWX, Tooth #18 has mesial amalgam restoration with overhang and very light contact. What lead to this?
A wedge was not placed
| right or poor adaptation of matrix band
197
Position of incisal portion of matrix band?
1 mm above adjacent marginal ridge
198
What first, wedge or matrix
matrix first, wedge after
199
Restoration of class 2 for posterior with heavy occlusion – amalgam, composite, microfill
amalgam
200
What is the hardest (most rigid) gold?
Gold Type IV
201
When do use base metal opposed to gold?
Long span bridges (FPD)
| - need it be more rigid = more base metal
202
Ductility
– gold’s ability to be worked into different shapes
deform (without fracture) under tensile strength; ability to stretch into wire
gold is the highest
203
Only advantage of porcelain over gold:
esthetics.
204
Advantage of gold on occlusal surface, porcelain in facial surface:
conserve tooth structure, minimal reduction?
| Gold is compatible in wear with natural tooth & is more conservative, porcelain gives esthetics.
205
Reduction dimension for functional/non-functional cusps in gold and PFM
Gold: functional = 1.5, non-function = 1. PFM = 1.5-
| 2mm
206
Why do we bevel the edge of gold-
finish margins better, marginal stability & better adaptation
207
Weakest part of the gold mod inlay is?
cement layer (cement = weakest part of cast gold restoration)
208
bonding for gold?
Zinc phosphate
209
Zinc phosphate can be used to bond what
gold and PFM
210
PFM bonded with what
zinc phosphate
211
GI as bond is used for
zirconia
212
bond zirconia with
GI
213
```
What is the most accurate pulpal test to determine vitality of a tooth with a full-gold crown?
Electric testing
Percussion test
Palpation test
Thermal test
```
Thermal test
214
Recently placed gold inlay on upper tooth is opposing lower amalgam, what is the most common reason for pain afterwards?
Galvanic shock
| - Galvanic shock Sensitivity - choose this if only question says opposing dissimilar metal.
215
why can gold casting go wrong?
hygroscopic expansion
setting expansion
hygroscopic expansion
| Plaster expands during casting so gold casting will be smaller than expected
216
advantages of burnishanility
strength
217
Main Disadvantage of gold inlay
a. deforms under load
b. wear opposing
c. cement is soluble
d. possible attrition
a. deforms under load- since it is high noble gold and softer, it may have higher creep
+ cement is not soluble (for gold it's zinc phosphate)
218
How to remove a gold inlay?
Section isthmus and remove in 2 pieces
219
What is the reason to burnish gold to the margin?
Acute angle of gold margin
220
Which is a characteristic of a gold inlay?
Axial walls converge toward the pulpal floor (axial pulpal walls = divergent prep)
- From facial to lingual, the axiopulpal line angle of an onlay preparation is longer than the axiogingival line angle (if it were not, the
preparation would be undercut and the onlay would not seat). For an MOD onlay prep, the axial walls must converge from the gingival
walls to the pulpal wall (for the same reason, the onlay would not seat if they diverged).
221
removing cusps for inlays/onlays: retention or resistance?
retention
222
intercuspal space in inlays/onlays: retention or resistance?
resistance
223
marginal ridges: retention or resistance?
resistance
224
loss of marginal ridges: retention or resistance?
both
225
Isthmus of MOD prep extends over 1/3 of intercuspal dimension, how to treat? amalgam, crown, onlay, inlay, crown
onlay
| Inlays when less than 1/3 intercuspal dimension is prepped
226
how much intercuspal needs to be prepped for inlay?
less than 1/3
227
removing cusps affects retention or resistance?
retention
228
When is onlay indicated?
when cuspal coverage is needed or when cusp is undermined by not enough dentin
229
Which is the only surface not beveled for an onlay?
Pulpal
230
Dentist has to reduce a weak cusp during onlay preparation is to:
a) outline form
b) resistance form
c) retention form
c) retention form
| Cuspal coverage – retention form
231
Pt w/ onlay, 3yrs later sensitivity
- cement wash out?
232
Use of indium (tin & iron) with alloy is mainly to
provide chemical bond with porcelain
233
Purpose of addition of tin and iron to metal ceramic allows:
Chemical bond, covalent bond with porcelain
234
Cut onlay & find out margin of crown w/in 1 mm of interseptal bone
a. pack cord, take imp
b. crown length surgery
c. use amalgam
b. crown length surgery----impinges biologic width
235
When is the best case to use an inlay?
Patient with low caries index
236
can't use inlay if
high caries risk!!
237
Where is the MOD inlay hitting when it contacts early during seating?
Interproximal
238
What causes most post-op sensitivity in direct inlay:
Polymerization shrinkage
239
Patient receives a blow to the chin. He has a MOD inlay placed on the maxillary molar 3 months earlier. Now the patient has a
vague pain on biting, there are no other symptoms. Why? maxillary sinusitis, M-D fracture
M-D fracture
240
Reasons of reduction of tooth for MOD inlay except: amt of enamel on teeth
Reasons of reduction of tooth for MOD inlay except: amt of enamel on teeth
241
cement for porcelain onlay
HAS TO BE RESIN
242
Cement onlay & you see black lines few months later:
MICROLEAKAGE
243
Coefficient of thermal expansion is most for which material?
Tooth
244
Linear thermal coefficient is most for tooth- gold- amalgam- composite
composite
245
Porcelain Strength:
(weakest) Feldspathic porcelain
246
14-year-old with MOD restoration, decay interproximally and undermined enamel in all cusps.
- onlay
- inlay
- crown
- crown (b/c all cusp has undermined enamel)
247
MOD amalgam that exceeds 1/3 distance of cusp height, what would you do? MOD amalgam, MOD composite, MOD onlay, MOD
inlay
MOD onlay
248
Common feature between porcelain veneer and all-ceramic crown preparation –
rounded internal
249
What is the most important thing for retention?
Surface area
250
Most lab complain that the tooth is
under reduced.
251
Porcelain under compression forces - weaker or stronger?
stronger
252
Porosity in PFM
– inadequate condensation
253
What is the weakest porcelain?
Feldspathic
254
Best material to oppose a porcelain crown?
Porcelain
255
Silver turns porcelain (PFM) what color?
Green
256
What turns a PFM green?
Silver
| Silver (Ag) is not considered noble; it is reactive & improves castability but can cause porcelain “greening.”
257
What component makes a PFM green in the cervical 1/3?
copper
| - at the margin its copper, other places its silver
258
What parts of tooth prep can be managed by operator/dentist: parallelism, surface area, length, circumference
parallelism
259
what does porcelain do to opposing teeth
wear of enamel
260
What is function of opaque porcelain EXCEPT:
mask metal framework
to help come up with a base/stump shade
for initial bond to metal
to decrease contamination of additional porcelain with metal in ensuing firing and baking procedures
to decrease contamination of additional porcelain with metal in ensuing firing and baking procedures
261
When you receive a crown back and want to seat it what is the first thing you check for?
a. Shade (Aesthetics) or internal
b. Proximal contacts
c. Margins
a. Shade (Aesthetics) or internal
262
Where will you place the margins in an anterior PFM prep:
Subgingival
263
Minimum incisal reduction in anterior PFM:
2 mm
| - Mostly for esthetics & thickness of porcelain (translucency layer)
264
Facial reduction for PFM at gingival 3rd is
1.5mm
265
How much reduction would you do for a PFM crown on anterior?
1.5mm on facial incisal plane, not incisal angle
266
When you have a short crown for PFM, what do you do to increase retention of the crown?
Place proximal boxes & vertical
| grooves to increase retention.
267
What causes the most retention of crown? Axial taper, surface area, surface roughness, retention grooves
Axial taper,
268
How do you make sure your all-ceramic restoration does not fracture?
must have NOT LESS than 1.5mm porcelain @ occlusal
269
Functional cusp bevel for what
structural durability
270
Why do a functional cusp bevel on a crown prep?
To prevent cusp fracture & for proper casting/fabrication of the crown
- Bevel on functional cusp for extra room for porcelain. Ideal is 2 mm reduction.
271
In PFM, porcelain fractures because the junction should be?
Right angle, not round
- Junction between tooth & metal = right angle
- Junction between metal & porcelain should be rounded
272
When you want to cement crown, what is the sequence? L
ook inside the crown (internal fit), contacts, then margin
273
etch enamel for porcelain?
NO!
274
What is NOT the reason why you use resin cement on all porcelain restorations? for added retention, to fill small openings at
margin
to fill small openings at
| margin
275
You have a patient who wants an all porcelain on # 8 – the incisal edge keeps breaking off and you have to come in to repair, why
does it keep breaking off?
Because the anterior guidance and the protrusive movements/clearance space was not properly
calculated/maintained
276
```
#10 PFM on a patient looks longer than #7. All of the following may be the reason why the crown looks like this except? Incorrect
shade, insufficient tooth prep , too thick metal, too thick porcelain
```
```
Incorrect shade
others yes (insufficient tooth prep , too thick metal, too thick porcelain)
```
277
What didn’t cause the unaesthetic opacity of crown? shade selection; under-prepared tooth, too thick metal,
too thick base porcelain
shade selection;
278
What could the reason be if you see opaque white porcelain in the incisal 1/3 facial of the PFM crown:
inadequate reduction of the
| inciso facial part of the tooth
279
why would incisal edge of anterior PFM be opaque?
improper second plane of reduction
280
Lab overbulks porcelain, why?
Not enough reduction on tooth, compensate for 20% shrinkage
281
3⁄4 gold crown vs full is advantageous except for?
LESS retention than full crown
282
Resistance to lingual displacement of 3⁄4 crown? Lingual wall (of groove), facial wall of groove, facial aspect of prep
Lingual wall (of groove)
283
Advantage of a direct composite vs. a veneer?
Direct
| composite is only 1 appointment vs. veneer is at least 2
284
Most technique sensitive part of placing veneers? Preparation, color match, impressing
Preparation
285
Pt had veneers cemented with light cured resin. Now, comes back few weeks later with brown staining at gingival margins. Why?
Microleakage, not enough cement, etc
Microleakage
286
Veneer after a month time has some brown stain: not enough cement at margin, Microleakage
Microleakage
287
The dentist cements the porcelain veneer with light cured resin and the patient returns with brownish discoloration at the margins,
why?
not enough cement or microleakage (depends on duration of pt return)
288
How much tooth structure needs to be removed on the mid facial for a porcelain veneer?
0.5 mm
289
Patient has a veneer on incisal edge, small piece of porcelain chipped off and wants you to fix the chip only, what is the sequence of
events:
microetch/micro abrasion, acid-etch, silanate, and bonding agent (MAS Bonding)
- Silane = porcelain tx to help it stick to bonding agent
290
Repairing porcelain veneer with composite
--> microetch, etch, silanate, resin
291
What do you use to cement a veneer?
• Resin cement
• Polyacrylic acid
* Resin cement
| * Polyacrylic acid is etchant for GI
292
Opaque coming through on veneer, what’s the problem?
Veneer under prepped
293
Order of bleaching and veneering process:
bleach, wait 2 weeks, prep tooth, cement
294
When will you bleach teeth in anterior veneer prep?
Before veneer prep, wait for 2-3 weeks
After prepping veneer and then bleach
After cementing veneer and bleach
Before veneer prep, wait for 2-3 weeks
295
Pt has veneers from 6-11, which fluoride do you use to not stain the veneer?
A. Stannous Fluoride (stains)
B. Sodium Fluoride**
C. Acid Fluoride
B. Sodium Fluoride**
296
In-home bleaching kit, what’s the percentage?
10% carbamide peroxide
297
Material used for mouthguard vital bleaching -
10% carbamide peroxide
298
H2O2 in-office bleaching
– 35%
299
Home bleaching causes what?
sensitivity
300
Most successful teeth for bleaching?
Aged yellow staining
301
What is the most effective way of bleaching teeth?
In-home vital bleaching
302
Non vital bleaching is with?
35% hydrogen peroxide, carbamide peroxide, and sodium perborate.
303
Bleach most often used in internal bleaching:
sodium perborate
304
Difference b/t dentist and home bleaching -
strength of peroxide
305
Best way to decrease gingival irritation w/ home bleaching?
Well-fitting custom trays
306
Most common complication of internal bleaching:
cervical root resorption
307
What is worse outcome of nonvital bleaching (internal bleach for endo)?
internal root resorption /CERVICAL RESORPTION.
308
```
You are about to prep a tooth for PFM crown, patient also needs teeth bleached, how do you go about it? –
Bleach first, wait 2
weeks, prep tooth, then restoration.
Bleach and prep 1st, then wait 2 weeks,
Bleach last after prep and crown
```
Bleach first, wait 2
| weeks, prep tooth, then restoration.
309
How long after vital tooth bleaching can you bond resin to it? 24 hours, 3 days, 1 week
1 week
310
Patient is complaining about a very light colored anterior PFM crown she had done sometime ago, there is nothing clinically wrong
with the crown. What do you do Doctor? Bleach natural teeth, re-do the crown, put a darker shade composite on crown
Bleach natural teeth
311
#8 PFM is too light but good margins and been there for 10 years
– vital night guard bleaching
312
```
45 yr. old woman. Anterior crown placed 10 years ago & color doesn’t match natural teeth now, appears clinically acceptable & has
good margins, what will you do?
a. vital bleaching
b. new crown
c. microetch and composite bond
```
a. vital bleaching
313
The prognosis for bleaching is favorable when the discoloration is caused by
a. necrotic pulp tissue
b. amalgam restoration
c. precipitation of metallic salts
d. silver-containing root canal sealers
a. necrotic pulp tissue
314
The office bleaching changes the shade through all except:
a. dehydration
b. etching tooth
c. oxidation of colorant
d. surface demineralization
b. etching tooth
315
What type of bond is composite on tooth structure?
a. chemical bond
b. mechanical bond (micromechanical)
c. organic coupling
d. adhesion
b. mechanical bond (micromechanical)
316
Two things that account for a successful posterior composite restoration?
Type of resin and type of prep
317
Post-operative MOD composite pain, most likely due to?
Hyper-occlusion
318
Few days after placement of composite restoration complains of pain especially with biting but relieved by cold:
check occlusion
319
What indicates the design of composite class I preparation
Only incorporates pits of lesion
2mm pulpal floor depth
45-degree bevel cavosurface
Only incorporates pits of lesion
320
When doing a class 1 composite, what is the requirement:
contain to only pit and fissure caries
321
What determines composite class 2 prep? Extent of caries, Access
Extent of caries,
322
When do you replace class 2 composite?
Recurrent decay
323
You are doing a composite slot on mesial and distal of 1st molar, you decide to connect the composites by crossing the oblique
ridge, why?
when oblique ridge is less than 1.5mm you involve it
324
Class II prep into cementum, how should you restore? GI, Hybrid, non-restorable
GI
325
Small occlusal fillings need to be done on posterior, what do you use – amalgam, composite, GI
composite
326
Large MOD composite, what’s disadvantage?
Occlusal wear
327
What is not a class I cavity preparation? gingival 1/3 of #19, Lingual pit of #7, Lingual pit of #18
gingival 1/3 of #19
328
amount of stress on composite depends on
C-factor (bonded/unbonded)
329
Which has the highest C factor or stress on it?
Class 1 & class 5
330
Which part of composite stains the most - gingival proximal, facial proximal,
lingual proximal, or occlusal
gingival proximal
331
Secondary caries is most likely at gingival margin.
gingival margin.
332
Trans illumination is useful in the diagnosis of Class 1, class 2, class5, Class III
Class III
333
What do you place on a 75 y/o patient with ~ 8 class V carious lesions?
GI
334
65 y/o pt shows several new caries in molars and premolars class V, what material would you use:
a) amalgam
b) composites
c) glass ionomer
c) glass ionomer
335
#5 cervical lesion Class V onto root:
Bevel enamel, 90 butt margin on cementum
336
What is not an indication for restoring class V abfraction?
a. sensitivity
b. esthetics
c. prevention of decay
d. prevention of further structure loss
e. restoring physiological contour
a. sensitivity
337
Class IV composite, you notice it is too light two weeks later, how do you treat?
Add composite tint or do direct facial composite in
| new color
338
If a dentist notices that a large but acceptable composite is too light a few weeks after placing it, what should he do?
Veneer with
| composite
339
Class III that extends to facial. The restoration is stained but margins are perfectly sealed. However, they have bad color & pt wants
it fixed. What should you do?
Remove 1 mm prep and add more composite
340
Recently placed a class III comp, pt isn’t happy with it and has a huge staining on margins what to do?
Replace
341
After caries removal, sound tissue is in cementum. How do you restore?
Build up with GI and place composite
342
If a Class III prep is subgingival?
Restore with GI, followed by composite
343
Class III composite w/ radiolucency under it, this could result from all the following except? liner, recurrent caries, contraction from
shrinkage of curing, composite contraction
composite contraction
344
Main advantage of doing direct composite over composite onlay?
a. less Shrinkage
b. better marginal adaptation, seal
c. greater hardness and wear resistance
b. better marginal adaptation, seal
might be less shrinkage, second best
345
Most important factor when placing a composite in posterior teeth?
Case selection and technique
346
Sensitivity after placing composite restoration in posterior is mostly likely caused by? due to resin polymerization shrinkage in
margin, shrinkage floor.
due to resin polymerization shrinkage in
| margin,
347
You place a conservative composite on a posterior tooth and the patient returns due to sensitivity. What is the most likely reason?
Putting large amount of comp while filling, microleakage, trauma to dentin during preparation, etch causing pulpal pain, bacteria, gap, cuspal
microleakage, trauma to dentin during preparation
348
Most common reason for replacing posterior composites: recurrent caries, inadequate margins, fracture of composite
recurrent caries,
| - Two main causes of posterior composite restoration failure: secondary caries and fracture (restoration or tooth)
349
After placing a crown with composite resin 6 month ago, there is discoloration around the porcelain gingiva (brown color). What is
the cause?
discoloration of resin
350
An anterior composite placed 10 years ago without caries, what is the most common reason to make a new one?
color change/staining
351
How long should you wait after bleaching to do a composite on an anterior tooth?
1 week at least
352
How long after vital tooth bleaching can you bond resin to it? 24 hours, 3 days, 1 week
1 week
353
Why do you bevel when placing anterior composite?
More surface area
354
Which one is not reason for post-op sensitivity Class I comp?
cusp deformation due to shrinkage force
355
You have a pt. with a composite filling that complains of pain to cold during chewing, you ditch it out with a bur, no more pain.
What was the cause of the pain?
Polymerization Shrinkage
356
Post-op sensitivity on MOD so removed a portion of the occlusal & placed more composite. What was cause: Fracture
Microleakage
Inadequate margins and water coming out of the tubules
Acid etch
Compression pulling on cusps
Compression pulling on cusps
357
Post-op sensitivity from a recently placed Class I composite. Everything could be a reason for sensitivity EXCEPT:
1 etchant causes pulpal sensitivity
2 shrinkage causing gap for microleakage of bacteria
3 shrinkage causing gap for movement of fluid out of pulp
4 polymerization shrinkage that causes cuspal shrinkage
4 polymerization shrinkage that causes cuspal shrinkage
358
When do you see microleakage with composite restoration done without rubber dam?
Same amount of time as if done with rubber dam
2 weeks later
2 months later
2 weeks later
359
Class II composite done without rubber dam, how long until you see microleakage – 2-4 weeks, 4-6 weeks, same time as with
rubber dam on
2-4 weeks
360
Highest chance of leakage under rubber dam? Holes too wide, Holes too far apart, Holes too close
Holes too close
361
What is not an advantage of rubber dam when compared to not using it? Improved properties of materials, shortens operative
time, facilitates the use of water spray
facilitates the use of water spray
362
Placement of rubber dam affect the color selection by
dehydration of tooth gives inaccurate tooth shade
363
“W” on the rubber dam clamp means it is?
Wingless
364
Pt has composite restoration with severe pain with localized swelling, Tx is?
Incision & Drainage
365
Pt had a bunch of little pits in #8 central incisor, how would you fix it? Composite over pits only, or over entire tooth, or veneer w/
porcelain, etc
Composite over pits only
366
Pt complains of a marginal stain on #8, what do you do?
Polish it
367
Patient’s chief complaint is #8 and #9 don’t look right. Picture shows nothing is wrong with #9. #8 has extra enamel at the incisal-
distal aspect. What do you do?
Shave the inciso-distal aspect of #8.
368
All of the following are an indication for putting a temporary on a deep caries and restoring at a later time except? Lack of time due
to it being an emergency appt, weakened dentin under cusps, to assess pulp condition
Lack of time due
| to it being an emergency appt,
369
Photo initiator of resin composite?
Camphoroquinone
370
Diketones activate by?
Visible light
- Composite resins contain alpha diketones as photoinitiators. Blue light to produce slow reactions. Amines are added to accelerate
curing time. Crosslink reaction.
371
The most radiopaque in composite is:
Barium (it is a metal)
372
QUESTION: Most radiopaque in porcelain:
a. barium and zirconium glass
b. silica
c. quartz
a. barium and zirconium glass
373
Heat-cured indirect composite (stronger) vs direct composite. Which is incorrect?
a. Heat composite is harder
b. Heat composite is more resistant to abrasion
c. Heat composite is done indirectly so Less irritation to tooth due to less shrinkage
d. Heat indirect composite has better bonding to the dentin and enamel
Heat indirect composite has better bonding to the dentin and enamel
374
Which composites have more color stability?
light cure due to TEGDMA (Triethylene glycol dimethacrylate)
| - HEAT CURED (light cured) RESINS HAVE SUPERIOR COLOR STABILITY
375
With TEDGDMA and HEMA:
light cure to maintain proper shade
376
What is importance of light cured vs self-cured in terms of shade balance?
less number of nitrates when you light cure
377
What is false about LED vs halogen curing lights?
a. blue light is 340-370
b. battery powered/cordless LED is acceptable
c. LED lasts longer than halogen
d. something about a photoinitiator
a. blue light is 340-370
Blue light is not 340-370, actually 450-750
- We use LED curing light b/c has more narrow spectrum, less heat generated, light bulb last longer & generally smaller.
378
Lasers and LED lights don’t cure all resins b/c some resins photoinitiatiors have require light sources is out of range:
true and correct
| logic.
379
Which of the following will be not be good against enamel? – Porcelain, Hybrid resins, enamel, amalgam , unfilled
resins
Porcelain, Hybrid resins,
| - Hybrids have silica filler, which increase hardness wear resistance & is the most abrasive.
380
Worse restorative material for canine restoration? gold, glass ionomer, composite, amalgam
- Worst will be Composite > GIC> Amalgam> Gold (according to dental decks composite not given for class 3 DL in canines)
381
For a class 3 on a canine, all are appropriate except: gold inlay, composite, amalgam, glass ionomer
composite
382
what does etchant remove
smear layer
383
GI adhesion
chemical
384
Components of GI CEMENT:
alumina silicate and polycarboxylate
385
GI compressive and tensile strength?
high compressive, low tensile
386
Beveling in acid etching composite:
Increase surface area
387
Does etchant provide chemical bond?
no
388
What does acid etching NOT do? Increase surface area, remove debris, increase wettability of enamel, or decrease irregularities at
cavosurface margin.
decrease irregularities at
| cavosurface margin.
389
What does acid etching NOT cause? Acid-etching does not cause. Reduced leakage, better esthetics, increased strength of
composites
increased strength of
| composites
390
Acid-etching does not cause: Reduced leakage, better esthetics, increase composite strength
increase composite strength
391
what does etch do
remove smear layer and form HYBrid layer with resin
392
Hybrid layer -
primer within intertubular dentin
393
If contamination occurs after etch,
Re-etch
394
The most unreliable etch system?
Self-etch (all in 1 system – etch, prime, bond)
395
Function of filler in resin—
strength (reduces polymerized shrinkage & increases hardness)
396
Filler size in composites:
Larger fillers have more strength, but do not polish as well
397
Dentist who work with HEMA (methacrylate, acrylic) can have what kind of complication?
Contact dermatitis
Anaphylaxis
Immune mediation reaction
Arthus phenomena
Contact dermatitis
- Think acrylic allergy due to monomer
398
What acid is in GI cement?
silicate glass powder & polyacrylic acid
399
Glass ionomer, what is the liquid made of?
Powder = fluoroaluminosilicate glass; Liquid = polyacrylic acid
400
What is the acid in glass ionomer? Phosphoric acid, Polyacrylic acid
Polyacrylic acid
401
Why do you use a cool glass slab? More powder incorporated, less powder incorporated, decrease working time
More powder incorporated,
402
Purpose of a cool glass slab when mixing cement is:
to incorporate the most powder into liquid as possible.
403
Which indicated for high caries risk or multiple class Vs?
Glass Ionomer
404
What is the most practical way to seat a casting at the time of cementation?
Grind the inside away
405
To make sure casting seats, do the following EXCEPT:
• Increase thermal expansion of investment
• Mix cement thin
• Remove internal nodule with occlude
• Remove internal nodule with occlude
406
If you have a bubble in an impression for a crown that is not visible, what is going to happen with the crown when comes from the
lab and you try to seated in the mouth?
Crown does not seat
407
Small void in die, crown was processed, what will happen?
Crown will seat in die, but not on tooth
408
What won’t affect metal casting seated on master cast?
Impression inaccuracies
| - It won’t fit the tooth but will fit the cast.
409
You notice a void on occlusal of cast. Crown will:
a. Fit on die and not on tooth
b. Fit on tooth and not on die
c. Fit on both
d. Not fit on either
a. Fit on die and not on tooth
410
What do you not do if your crown doesn't fit?
Don’t change the cement ratio mixture
411
Why do we lute all ceramic crowns with composite/resin? Increase strength, color stability, sealing of margins, enhance retention
Increase strength
| Composite Resin - the luting material of choice to cement a ceramic crown and can provide the strongest bond.
412
Why don't you use GI resin cement in cementation of all ceramic restoration? I
ts expansion could cause cracking of porcelain.
413
QUESTION: Sensitivity of pulp in regards to cement, which is correct?
Resin ionomer and glass ionomer cause highest pulp sensitivity.
414
Which cement is the easiest to remove after procedure?
Zinc Phosphate cement
415
Zinc phosphate pH is 3.5, what is the significance of that?
This might also cause pulp sensitivity
416
ZOE pH?
~7
417
What component of cement contributes to adhesion? Polycarboxylic acid, benzoyl peroxide, others,
Polycarboxylic acid
| - Polyacrylic side group à chelation between carboxyl groups and calcium in tooth.
418
RMGI: What is the advantage beside fluoride release?
Ionic bond btwn enamel and dentin
| - GI forms ionic bonds
419
You place a CaOH on the tooth for a direct pulp cap, what else is needed?
Placement of a liner
420
Pulp capping:
Use CaOH & in order to protect the pulp, put 2mm thickness of liner/base above CaOH
421
How do you improve the success of calcium hydroxide on a direct pulp cap?
Place GI liner over calcium hydroxide
422
Which procedure is most unsuccessful in primary tooth with deep caries? Direct pulp cap, indirect pulp cap, pulpectomy, partial
pulpectomy, pulpotomy
Direct pulp cap
423
The strength of Zinc Oxide Eugenol (IRM) can be increased by adding what?
Methylmethacrylate (MMA)
- Zinc oxide eugenol is IRM but there’s an extra component that makes it IRM which is the methylmethacrylate, which is an inactive
ingredient.
424
```
What is the material in reinforced IRM that give it strength?
A. amalgam powder
B. Zinc phosphate
C. Poly methyl methacrylate (PMMA)
D. Titanium powder
```
C. Poly methyl methacrylate (PMMA)
425
Zinc eugenol is a good temp filling bc: gives a good bacterial seal, high compressive strength, high tensile strength, good biological
seal.
gives a good bacterial seal
426
The main component of any root sealers is?
Zinc oxide
427
What do you use to fill a root canal on the primary tooth?
ZOE w/out catalyst
| - Lack of catalyst gives it adequate working time to fill canals
428
```
What do you fill a root canal with on a primary tooth?
• Gutta percha
• Sealer alone
• ZOE with accelerator
• ZOE without accelerator
```
• ZOE without accelerator
429
Zinc phosphate cement is used as luting agent. The initial acidity may elicit a traumatic response if:
a. Only a thin layer of dentin is left btwn cement and pulp
b. very thin mix of cement is used
c. tooth has already a previous traumatic injury
d. No cavity varnish is used
A. a, c, & d
B. an or d
C. b only
D. all of the above
D. all of the above
430
If you add BIS-GMA to PMMA (acrylic)
à increases strength or results in the doughy texture to have more working time
431
Crosslinking factor of P-MMA? BIS-GMA, benzoyl peroxide
- Bis-GMMA- provides the CROSS LINK
432
Cross-linking in polymers leads to what?
Better Strength
433
Addition of long cross-linking chains in PMMA is for what reason? increase strength, allow doughy consistency before set, allow for
addition of more powder without crazing, prevent shrinkage
increase strength
434
By having excess amount of monomer in acrylic, it can create excessive amounts of what: shrinkage, expansion, thermal conduction
shrinkage
435
Adding more monomer increases:
a. Expansion
b. Shrinkage
c. Brittleness
d. Harness
Shrinkage
436
critical pH of fluoroapatite and enamel
4.5 vs 5.5
437
when to do sealants
6-12 yo
438
Sealants adhesion -
mechanical microretention binding to tooth
439
Contraindication of sealant:
when you have rampant or gross caries
440
A child with no decay but deep pits and fissures, what is the Tx plan?
Sealants
441
Patient has deep grooves but no decay on permanent molars, what do you suggest?
Sealants
442
High caries risk patient, when is he indicated for sealants? Obvious clinical cavitation on the occlusal, deep fissures without caries
deep fissures without caries
