Important solved Questions for NBDE part2-1

QUESTION: Tx of root surface caries
gic true

QYESTION:what kind of dentin should not be restored? Eburnated dentin(Sclerotic dentin)

QUESTION: Fluoride works best onr?
Smooth interproximal surfaces.

QUESTION: Smooth surface caries most likely due to?

QUESTION: What caries lesion has a V shape pointing to pulpsmooth caries true

QUESTION: Which of the following is a factor for smooth caries and sugar in-take?
– Consistency–consistency b/c if it’s the sticky type it stays on the tooth longer allowing bacteria
to keep ph lower longer

QUESTION: Caries in children depend most on: amount, consistency, time
all true

QUESTION: occlusal caries where is base and cone?
Triangle Base towards dej and apex towards tooth surface

QUESTION: 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. Both bases facing DEJ( answer both bases facing dej)

QUESTION: DEJ- diff btw smooth caries(conical), occlusal (apex at occlusal), interprox (apex
at DEJ) true

QUESTION: conical shaped caries w/ broad base with apex towards pulp is commonly seen in?
A. Root caries
B. Smooth caries TRUE
C. Pit/fissure caries

QUESTION: Diagnosis of pit and fissure caries,

– explorer catch,

QUESTION: enamel caries best detected by explorer catch
-, true

QUESTION: 40 y pt w/ all 32 teeth. No cavities. Has stain & catch in pit of molar. what do you
a. watch and observe
b. sealantc. composite

QUESTION: if you inadvertently seal over caries what happens?
Arrested caries.

QUESTION: If you feed a person through a tube,
then you decrease risk of caries true

QUESTION: mechanism of caries indicator: enters the dentin and binds to the denatured
• A colored dye in an organic base adheres to the denatured collagen which distinguishes
between infected dentin and affected dentin

QUESTION: What type of caries detection is the Dyfoti used for?
Class I Class II, Class III {all occlusal and interproximal} answer- all
QUESTION: DaignoDent is Class I
– ONLY OCCLUSAL CARIES (pit and fissure) true
QUESTION: Number of people with caries or other stat your looking for in your office this year
is 300 out of 1000, last year it was 200, so what is it for this year?
300/1000 im pretty sure incidence
is NEW cases. And the answer is 300-200/1000= 100/1000 =0.1 DESCRIPTIVE STUDY
QUESTION: Radiographic decay most closely resemble which zone of carious enamel?
Body zone*,
dark zone,
translucent zone,
surface zone
QUESTION: Know what DMFS stands for decay missing filling surface
QUESTION: DMFS is for surfaces including 3rd molars
QUESTION: in DMFS “ s” stand for ———–
measures how permenant dentition is affected by caries
QUESTION: DMFT is for permanent teeth in WHO modification 3rd molars are included
QUESTION: Which race has a higher F in DMFT index:
Whites trueQUESTION: Which population has the most number of unrestored caries:
QUESTION: deft= for primary (e=extraction)
QUESTION: which of the following acronyms is only used for kids?
QUESTION: Whats the D__ the one that’s only three letter system of tooth carries tracking, what
can it not do?-
Track how teeth were lost. true
QUESTION: Differences between 245 and 330 burs245 bur is 3mm in length, 330 is 1.5mm. All other dimensions the same except for length.
QUESTION: burs 245 vs 330 question = 245 is longer nd sharper angle!!! (3mm) 330 is 1.5mm
in length.
QUESTION: Example pear shape bur- 56 or 699? (Isn’t pear shaped…more like a 330?)
Pear = 329, 330, 245 (330L)
QUESTION: Bur used that converges F and L walls? #245, 7901, 245
245 = 330L = pear and elongated bur, 169 = tapered bur, .9 diameter
QUESTION: What bur do you use to shape convergent walls for amalgam
QUESTION: Which bur do you use for peds? A.245 B.18 C.51?
I think its 330
QUESTION: which is best for occlusal convergence in a prep,
245 true
QUESTION: Diameter of 245 bur ?
QUESTION: What bur use for Amalagam retenetion in class II
– 245
QUESTION: Burs and smoothing out preps? More flutes and shallow, more flutes and deeper, less flutes and shallow, less flutes and deeper
QUESTION: More blades on bur:
QUESTION: Which burr is used to smoothe the prep?
Carbides for cutting diamonds for finishing true
QUESTION: Which high speed bur gives a smoother surface?
Plain cut fissure bur = best for smoother surface
cross cut fissure have a higher cutting efficiency
QUESTION: Bur used for polishing –
QUESTION: What is the correct method of excavation of deep caries.
Long bur from periphery to the center,true
large bur from center to periphery,
small bur from periphery to center,
small bur from center to the periphery
QUESTION: How to excavate if think might be close to pulp- **I would think you would use
the largest bur that fits, and go around the periphery and then towards the deepest true
QUESTION: Rotary hand instrument: high speed how many round per min? 200,000 rpm 25
QUESTION: know applications of chisel and spoon
Chisels are intended primarily to cut enamels, but spoons remove caries and carve amalgams
QUESTION: whats difference btwn an enamel hatchet and gingival marginal trimmer (both
GMT has curved blade and angled cutting edge. Enamel HA: 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 true
c. push/pull action instead of
QUESTION: what can’t you use to bevel inlay prep?
a. enamel hatchel
b. ging marg trimmer
c. flame diamond
d. carbide.
QUESTION: Instrument to plane gingival margin on a class II?• 2 with 3 number and 2 with 4 numbers
• Answer has 4 numbers – last number is different. Answer is not clear but it might be gmt it has
4 numbered formula for bevening the gingival margin
QUESTION: How do you bevel occlusal floor (gave list of instruments)
• 13,8
• 15,80
• 15,95
15 95 gmt for beveling distal gingival margins,15 80 for bevening mesial gingivalmargins
QUESTION: What instrument would not be used to bevel the gingival margin of an MOD prep?
Enamel Hatchet
QUESTION: Proper pulpal floor depth using Bur 245? true
is 3mm, so half of it is 1.5 mm which is proper pulpal floor depth
QUESTION: Hydrodynamic theory?
Definition: Postulates that the pain results from indirect innervation caused by dentinal fluid
movement in the tubule that stimulates mechanoreceptors near the predentin
QUESTION: Most commonly accepted theory of dentinal sensitivity?
A: Hydrodynamic theory z
QUESTION: You did a prep with high speed and diamond bur, tooth is sensitive, what is it about
bur and handpiece that it caused sensitivity?
A) Desiccation b) traumatized dentin? Heat
QUESTION: Most common pulpal damage from cavity prep
– heat
QUESTION: Which method of sterilization does not corrode instruments
– Dry Heat
QUESTION: which Sterilization most destructive to burs:
steam heat (autoclave)
QUESTION: What is best to sterlize carbide burs?
DRY HEAT or unsaturated chemical vapor->no corrode or dull
Ethylene oxide is for heat-sensitive instruments. true
QUESTION: Acute mercury toxicity for dentists, first signs – tremors
Paresthesia are early signs in mercury poisoning true
QUESTION: Subacute mercury poisoning symptoms – hair loss
QUESTION: Amalgam failure in primaryteeth
–moisture contamination
QUESTION: MOD amalgam with hole why?
-poor condensation
QUESTION: Most common reason for Amalgam fracture occuring in a primary tooth:
Inadequate cavity prep (especially the isthmus area)
QUESTION: Most common fracture of Class II amalgam:
isthmus true
QUESTION: Most common reason for failure of dental amalgam:
moisture contamination
answer-improper prep design- not enough depth true(first preparation fauilt den followed by
moisture contamination)
improper titrutration,
improper condensation
QUESTION: Patient had occlusal amalgam on tooth #30 few weeks ago, one day the dude went
to China-town 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. true
QUESTION: Page 48. Table 2-3….Prepped the amalgam, which is incorrect?:
Cavo surfaces is greater than 90 degree
QUESTION: Axial pulp should be ?
0.2-0.5 into DEJ
QUESTION: how far extend pulpal floor in class I amlgam cavity on primary dentition
a. 0.5 -1mm into dentin
QUESTION: Greatest wear on opposing tooth: amalgam, porcelain, microfill, hybrid composite?
QUESTION: Picture of deep amalgam with overhang but it looks really bad why does it look
like that?
QUESTION: What is wrong with marginal ridge of DO amalgam of #29? All of the following
(except maybe)?Occlusal wear,
wedge not placed right,
QUESTION: Which tooth will the matrix band be a problem with when placing a two surface
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) > Distal of max molar
QUESTION: worse restorative material for class3 canine? gold, glass ionmer, composite,
amalgum? worst will be Composite > GIC> Amalgam> Gold( according to dental decks
composite not given for class 3 DL in canines)
QUESTION: What is the corrosive phase of amalgam?,
Gamma2 – tin/mercury
QUESTION: What causes corrosion in amalgam? Tin
– The most common corrosion products found with conventional amalgam alloys are
oxides and sulfides of tin
– The chief function of zinc in an amalgam alloy is to act as a deoxidizer, which is an oxygen
scavenger that minimizes the formation of oxides of other elements in the amalgam alloys during
QUESTION: What type of Mercury is in the dental office?
QUESTION: most toxic mercury – methyl mercury (organic mercury) 28
Question: Type of mercury most hazardous to dentist health: ethylmercury,
QUESTION: Amalgam large condenser with lateral condensation is used in:
QUESTION: What type of amalgam needs to be condensed more?
Irregular or lathecut
Spherical requires light pressure,irregular more pressure
Large condenser produces light pressure,small condenser produces more pressure
QUESTION: Type of amalgam to use for best interprox contact of a CLASS II is
Admix Amalgam
QUESTION: Over triturating amalgam? sets too fast,
decreases setting expansion (increase compressive strength)QUESTION: Huge MOD in posterior à
restore with amalgam
QUESTION: MOD amalgam with tooth pain?
– fractured true
QUESTION: Tooth #30 has huge MOD amalgam and is deep. Hurts pt when he eats french
bread. what is the cause?
a. root fracture
QUESTION: Patient has a line of separation coronoapical (the wont say vertical fracture on the
test), the tooth is asymptomatic and it only hurts when patient eats French bread. What should
you do? Ext only if moveable pieces. If asymptomatic & not moveable àfair prognosis àRCT
QUESTION: days after placed an MOD amalgam pt present pain in biting and cold :
check occlusion. true
QUESTION: Placing pin in amalgam restoration, only choices I remember are 1mm pin or
1.5mm 2mm into amalgam true
QUESTION: Threaded pin- Amt in tooth/restoration/angulation
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 and parallel to the external surface between the pulp and tooth surface. Pins
should be 2mm into dentin, 2mm within amalgam, and Imm from the DEJ (to be safe) with no
bends in the pins.
QUESTION: Moisture contamination during amalgam restoration?
Decreased strength
QUESTION: If there is water while you are condensing amalgam, what happens? I put decrease
in strength
QUESTION: If there is water while you are condensing amalgam, what happens?
Delayed explansion (severe expansion, corrosion and decreased compressive strength)
QUESTION: Marginal leakage in an amalgam after 1 year, then what happens? I put that it
decreases. true
QUESTION: You have an amalgam that is ditched at the margin by .5mm and no signs of
recurrent decay what do you do:
observe/monitor, remove and replaceQUESTION: Where is it acceptable to leave unsupported enamel?
Occlusal of class V amalgam
QUESTION: What do class I & class V Ag ideal prep have in common
a. both slightly extend into dentin
b. both have flat axial & pulpal wall
QUESTION: Indirect restoration over amalgam:
in order to get ideal contours
QUESTION: What is the reason you would do MOD onlay vs Amalgam:
Better facial contour true
QUESTION: Class 2 amalgam vs class 2 gold inlay except:
line angles round in amalgam and sharp in gold true
QUESTION: Advantage of inlay over amalgam?
less tooth reduction true
QUESTION: Is the isthmus the same for inlay and amalgamà
YES {one third of intercuspal distance}
QUESTION: 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 aboveanswer- convergent walls and dovetail provides retention
QUESTION: Resistance form for amalgam prep :
bevel in the axiopulpal line angle to reduce stress and increase RESISTANCE form- “ways to
resist stress”.
Flat pulal floor also resistance feature
QUESTION: how to prevent proximal displacement of Cl II filling
– occlusal dovetail
QUESTION: What’s the best way to prevent proximal dislodgement/fracture of class II amalgam
• Retentive grooves*or (dovetail )
• converging axial walls (B&L walls)
• depth of prep
QUESTION: Proximal resistance form of amalgam restoration comes from what?
a. convergence of buccal/lingual wall
b. retention grooves in axiobuccal/axiolingual walls – for proximal resistance truec. Dovetail – provides retention form
resistance form is by rounding of axiopulpal line angle and flat pulpal floor
QUESTION: Mesial and distal walls of class I amalgam must be divergent not to undermine
marginal ridges true
RETENTION: 1st = BL walls converge, 2nd = Retention grooves/Occlusal dovetail
RESISTANCE: 1st = Flat floors, rounded angles (bevel in axiopulpal line angles) 30
QUESTION: How to account for mesial concavity on maxillary 1st premolar when restoring with
answer custom wedge or wedge wedging
QUESTION: BWX, Tooth #18 has mesial amalgram restoration with overhang and very light
contact. – ! (or poor adaptation of matrix band) true
QUESTION: premolar restored with open contact, why?
Wedge not placed right-I think ive seen this question before
Matrix band was not well adapted
QUESTION: Put wedge after matrix
QUESTION: From pt images, Which amalgam filling has the lowest Copper content?
One that looks corroded.
QUESTION: a pt presents with amalgams restorations in good shape, the dentist suggest to
change them for composites due to systemic toxicity of the amalgam what ethic principle is there
or the dentist is violating what principle:,
QUESTION: Definition of Veracity – doctor lied to patient about amalgam should be replaced
with composite, because amalgam causes toxicity
Malleability – deform (without fracture) under compressive strength; ability to form a thin sheet;
gold is malleable
Greatest malleability to least: gold, silver, lead, copper, aluminium, tin, platinum, zinc, iron, and
Ductilty – deform (without fracture) under tensile strength; ability to stretch into wire
greatest ductility to least: gold, silver, platinum, iron,nickel, copper, aluminium, zinc, tin, and
Gold inlay/onlay – divergent walls (2-5 degrees per wall), 30 degree bevel margins
QUESTION: onlay /retention:
2 to 5 degrees of taper per wall, as long a wall as possible, . primary retention is from wall
height and taper. Secondary retention is from retention grooves, skirts, and groove extensionsQUESTION: What is the hardest type of gold?
Gold Type IV
QUESTION: When do use base metal apposed to gold…. Long span bridges ?
QUESTION: Ductility –Golds ability to be worked into different shapes true
QUESTION: only advantage of porcelain over gold :
QUESTION: advantage of gold on occlusal surface, porcelain in facial surface—-conserve tooth
structure, minimal reduction…???? Gold is compatable in wear with natural tooth, porcelain
gives esthetics. Gold crown is more conservative. true
QUESTION: Reduction dimension for functional/non-functional cusps in gold and PFMgold-1.5mmfunctional,1mm non functional;
pfm 2mm functi 1.5mm nonfunctional

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