Pros Flashcards
porosity in PFM
inadequate condensation
What is the weakest porcelain?
Feldspathic porcelain
Best material to oppose a porcelain crown?
porcelain
What turns a PFM green?
silver
what component makes a PFM green in the cervical 1/3
copper
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
fact: Pt had veneers cemented with light cured resin. Now comes back few weeks later with
brown staining at gingival margins. Why?
Chromogenic bacteria
fact: Pt had veneers cemented with light cured resin. Now comes back few weeks later with
brown staining at gingival margins. Why?
Chromogenic bacteria
How much tooth structure needs to removed on the facial for a porcelain veneer?
___ mm
0.5 mm
order of what you do if veneer fractures:
mice, etch, microetch, etch, microabrasion,
silane
What do you use to cement a veneer?
• Resin cement
• Polyacrylic
resin cement
minimum incisal reduction in anterior PFM
2mm
Pt has veneers from 6-11, which fluoride do you use to not stain?
A. Stannous Flouride
B. Sodium Flouride
C. Acid Flouride
Sodium Flouride
10 crown on a patient is PFM. It looks longer than #7. All of the following maybe the
reason why the crown looks like this, except?
– Incorrect shade.
– insufficient tooth prep
– too think metal
– too thick porcelain
incorrect shade
Most common reason for PFM bridge breakage?
Firing schedule,
high contact,
inadequate design
inadequate design
What prevents lingual displacement of a ¾ crown?
a. lingual wall of grooves
b. facial wall of grooves
c. facial aspect of prep
a. lingual wall of grooves
Most important dimension that ensures the metal connector between abutment and
pontic is sufficient (in 3-unit fpd bridge)?
-buccolingual
-occlusogingival
-Mesiodistal
occlusogingival
How do you decrease the width of an artificial tooth? Deepen the facial line angle proximally and increase the interproximal embrasure, Deepen the facial line angle proximally and decrease interproximal embrasure, take the facial line angle labially and increase the interproximal embrasure, take the facial line angle labially and decrease the interproximal
embrasure.
take the facial line angle labially and increase the interproximal embrasure
The strength of soldered connector of FPD in enhanced? 1. Using higher carat solder, 2.
Increasing height , 3. Increasing width, 4. Increasing gap
increase height
key vs keyway: which one is on pontic and which one is on abudment?
Key is within pontic
keyway is within retainer
What is an active screw (post) vs. inactive post?
An active post is one that engages (screws into) the dentin in the canal space. Traditionally, the major
concern about active posts has been the potential for vertical fracture of the tooth during placement of the
post. active posts are indicated when the canal length is insufficient to gain adequate retention with a
passive post
Most important when selecting shade? value, transluceny, chroma,
concentration, and hue, color .
value
When you have color index of 100, which of the following is effected?
hue/value/chroma
value
When you add a different color to a resin, you increase what? Hue? Value? Chroma?
chroma
A dentist adjusts the shade of a restoration using a complementary color. This procedure will result in A. increased value. B. decreased value. C. intensified color. D. increased translucency
B. decreased value.
QUESTION: What cant you change: hue, increase value, decrease value, change chroma
increase value
What complement color to darken porc? gray, orange, ochre, violet
orange
Wavelength assoc with
- hue
- chroma
- value
hue
what is best way to determine value:
- open eye as wide as you can,
- arrange the shade guide in increasing value
arrange the shade guide in increasing value
The mesial angle of the ML of max 2nd molar occludes with what on the man 2nd molar
a. Mesial MB cusp
b. Distal MB cusp
c. Mesial DB cusp
d. Distal DB cusp
distal of MB cusp
What is Bennett angle?
a. it is the angle that is formed by the non-working condyle and the sagittal plane during lateral
movement
b. it is the angle that is formed by the condyle and the horizontal plane during protrusive movements.
c. It is an difference in condylar inclination between protrusive and lateral movements
d. It is the difference between in the condylar and incisal inclinations.
a. it is the angle that is formed by the non-working condyle and the sagittal plane during lateral
movement
what’s bennett shift?
lateral movement or working side
what type of bond is composite to tooth structure?
a. chemical bond
b. mechanical bond (micromechanical)
c. organic coupling
d. adhesion
mechanical bond (micromechanical)
2 things that account for successful post composite restoration
Type of resin and form of prep
C-factor?
bonded / Unbonded
what’s 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
MOD amalgam that passes the 1/3 distance of cusp height, do what – MOD amalgam, MOD composite, MOD onlay, MOD inlay
MOD onlay
main advantage of doing direct composite over composite onlay?
a. less shrinkage-
b. better marginal adaptation -
c. greater hardness and wear resistance
b. better marginal adaptation
Post op sensitivity on MOD so removed a portion of the occlusal and 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
Composite recently placed. all could be a reason for sensitivity. EXCEPT:
1 etchant causes sensitivity
2 gap causing microleakage of bacteria
3 gap causing movement of fluid out of pulp
4 polymerization shrinkage that causes cuspal shrinkage
3 gap causing movement of fluid out of pulp
Class 2 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 wks
Highest chance of leakage under rubber dam? Holes too wide, Holes too far apart, Too close
too close
W on the rubber dam clamp means it is?
wingLESS
Steps for adding to porcelain?
microetch, etch, silane, bond
what’s hybrid layer?
bonding agent to penetrate the intertubular dentin, forming the hybrid layer (resin-dentin interdiffusion zone)
denstist who work with HEMA( composite) can have what kinda complication?
contact dermatitis
what’s the powder of GI made of?
what’s the liquid of GI made of?
Powder: fluoroaluminosilicate glass
Liquid: polyacrylic acid
Why don’t you use GI resin cement in cementation of all ceramic restoration?
its expansion could cause cracking of porclain
Photo initiator of composite?
Camphoroquinone
Which composites have more color stability? why?
light cure due to Triethylene glycol
dimethacrylate TEGDMA
What is importance of light cured vs autocured in terms of shade balance
the less number of nitrates when you lightcure (mem)
curing light intensity
400
What is false about LED vs halogen curing lights:
a. blue light is 340-370to 450-750
b. battery powered/cordless LED is acceptable
c. LED lasts longer than halogen
d. something about a photoinitiator
e. Blue light is not 340-370
a. blue light is 340-370 to 450-750
T/F: 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
what kind of bond does GI form?
- Covalent
- Ionic
ionic
What is compomer?
combined benefits of composites (the “comp” in their name) and glass ionomers (“omer”).
-GI and Composite modified with polyacid groups, used in
low-stress-bearing areas (Less wear resistant than composite, Releases fluoride)Root caries and Class V.
RMGI is better
The strength of Zinc Oxide Eugenol can be increased by adding what?
Methylmethacrylate
what is IRM?
ZOE + MMA
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 (to increase
What is the material in reinforced IRM that give it strength: A. amalgam powder B. Zinc phosphate C. Poly methyl methacrylate** D. Titanium powder
PMMA
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. a or d
C. b only
D. all of the above
D. All of the above
What does BIS-GMA in PMMA do?
BIS-GMA is the x-linker in PMMA
By having excess amount of monomer in acrylic can create excessive amounts of what:
a. Expansion
b. Shrinkage
c. Brittleness
d. Harness
shrinkage
relation of gypsum W/P ratio to expansion?
• If the water/powder ratio is increased, the expansion is reduced
(DD, Op 123)
Gypsum: relation of spatulation to expansion
• The longer the spatulation time, the greater the expansion
DD, Op 123
Amalgam: relation of trituration to expansion
The longer the trituration time, the smaller the setting expansion
(DD, Op 11)
take an impression and lip immediately swells?
what do you give patient?
Angioedema
tx: C1 esterase inhibitor
Which of the following systems is thought to malfunction in the hereditary form of angioneurotic edema? A. C-1 esterase B. C-1q inhibitor C. CH50 consumption D. Serine phosphatase E.Complement synthetase
C-1 esterase
Alginate 100% humidity: Shrinks due to:
Imbibition/Syneresis/historgysm
syneresis.
when pouring gypsum material into an impression which material will cause the least amount
of bubbles? Polysulfide, polyether, silicone, irreversible hydrocolloid
silicone
____ gets affected by latex (handle with latex gets messed up the sulfer
in latex gloves that retards the setting of PVS addistion silicone))
PVS
arrange impression materials from best to worst dimensional stability
PVS (addition silicone), Polyether, polysulfide, condensation silicone, hydrocolloids
(DD, Pros 2012-13, pg 18)
wiki: dimensional stability is The degree to which a material maintains its original dimensions when subjected to changes in temperature and humidity.
Rate impression materials from greatest to least tear strength
polysulfide, PVS, polyether, condensation silicone, hydrocolloids
(DD, Pros 2012-13, pg 18)
Rate impression materials form most to least Stiffness
polyether, PVS, condensation silicone, polysulfide, hydrocolloids
(DD, Pros 2012-13, pg 18)
wiki: Stiffness is the rigidity of an object — the extent to which it resists deformation in response to an applied force.
Biggest disadvantage of polyether?
most likely to get stuck in mouth
DD, Pros 2012-13, pg 3
Most rigid impression material
a) polyether b) polysulfide c) PVS
polyether
what material you would not use for a single crown : a) polyether b) polysulfide c) PVS
polysulfide
condensation silicone releases
ethyl alcohol
Addition silicone releases
H2
The most stable elastic impression in moisture environment?
a. polyether
b. additional silicon
c. condensation silicon
d. polysulfide
addition silicone (PVS)