Differences between 245 and 330 burs: All other dimensions the same except for
length
shape
what angle they form. Correct Answer: length
245 bur is 3mm in length
330 is 1.5mm.
Which bur do you use for peds?
A.245
B.18
C.51 Correct Answer: A.245
Which is best for occlusal con...
differences between 245 and 330 burs all other dimensions the same except for
which bur do you use for peds
which is best for occlusal convergence in
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El Maestro – Complete| 1935 questions
Differences between 245 and 330 burs: All other dimensions the same except for
length
shape
what angle they form. Correct Answer: length
245 bur is 3mm in length
330 is 1.5mm.
Which bur do you use for peds?
A.245
B.18
C.51 Correct Answer: A.245
Which is best for occlusal convergence in a prep? Correct Answer: 245
(169 is better for occlusal)
QUESTION: Diameter of 245 bur? Correct Answer: 0.8 mm
What bur use for amalagam retention in class II?
245 or 330 Correct Answer: 245
Example of pear shape bur:
329,
330,
245 (330L) Correct Answer: 245 (330L)
245 = 330L = pear and elongated bur (tip is a cone)
Bur used that converges F and L walls?
#245,
7901,
169 (tapered bur, 0.9 diameter) Correct Answer: - If 169 is not thre, pick 245.
What bur do you use to shape convergent walls for amalgam -> Correct Answer: 169
Burs for smoothing out preps?
More flutes and shallow
,more flutes and deeper
less flutes and shallow
less flutes and deeper Correct Answer: More flutes and shallow (this is what red burs are)
More # of blades on carbide burs: Correct Answer: SMOOTHER, DECREASED CUTTING EFFICIENCY
Which high speed bur gives a smoother surface? Correct Answer: Plain cut fissure bur = best cross cut
fissure have a higher cutting efficiency
Bur used for polishing - Correct Answer: Carbide have more threads, STEEL FOR POLISH
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 Correct Answer: . Large bur from periphery to the center
- use the largest bur that fits, and go around the periphery and then towards the deepest
Rotary high speed, how many round per min? Correct Answer: 200,000 RPM
- slowspeed goes 20-30k average, endo = usually 800
Chisel vs spoon application: Correct Answer: Chisels are intended primarily to cut enamels, but spoons
remove caries & carve amalgams
What's the difference between an enamel hatchet & gingival marginal trimmer? Correct Answer: Both
chisels but GMT has curved blade and angled
cutting edge while Enamel HA has cutting edge in plane of handle
QUESTION: 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 Correct Answer: angle of the blade
QUESTION: What do you not use to bevel an inlay prep?
a. enamel hatchel
b. ging marg trimmer
c. flame diamond bur
d. carbide bur Correct Answer: enamel hatchel
What do u not use when beveling gingival margins? Correct Answer: Tapered diamond
- Causes enamel fracture
How do you bevel occlusal floor (gave list of instruments)
• 13, 8
What instrument would not be used to bevel the gingival margin of an MOD prep? Correct Answer:
Enamel Hatchet
Proper pulpal floor depth using Bur 245? Correct Answer: 3mm, so half of it is 1.5 mm which is proper
pulpal floor depth
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 Correct Answer: C) Heat
Most common pulpal damage from cavity prep - Correct Answer: heat, dentin dessication
What would cause displacement of odontoblastic processes?
Thermal
Dessication
Mechanical
Chemical Correct Answer: Thermal
What causes displacement of odontoblastic nuclei in the dental tubules?
- related to hydrodynamic theory I think so I put thermal
Acute mercury toxicity for dentists or subacute mercury poisoning symptoms, the first signs is:
, other are Correct Answer: nausea, other are muscle weakness
(hypotonia) and hair loss.
Mercury poisoning effects? Correct Answer: Loss of hair was a choice (I looked it up, and I think that is
the answer)
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? Correct
Answer: The prep was not deep enough.
When prepping the amalgam, which is incorrect?
Cavo surfaces is _______ than 90 degrees Correct Answer: Cavo surfaces is greater than 90 degrees
- Ideal cavo margin (margin between tooth and your prep) is 90 degree
Axial pulp should be?
______ mm into DEJ Correct Answer: 0.2 - 0.5 into DEJ
How far do you extend the pulpal floor in class I amalgam cavity on primary dentition?
- 1mm into dentin
- Just into dentin Correct Answer: Just into dentin
(total prep should 1.5 mm so 1 mm for enamel & ~ 0.5 mm for dentin
QUESTION: Greatest wear on enamel of the opposing tooth:
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,
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