Official NBDE Part 1 Study Q & A Thread

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Please post all study questions/answers for the NBDE Part 1 in this thread. Good luck!

As a side note, this is not the place for sales ads. Discussion of remembered questions appearing on the exam is also not permitted.

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If a patient comes with 19 restoration dislodged and broken ML cusp...what will be the result?

1. supraeruption of 14
2. Mesial drift of 19
3. Loss of vertical dimension
4. Canine discclusion
 
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no. transeptal are gingival, interradicular - periodontal
thts wht i thought...but like transeptal fibers, interradicular fibers goes from cementum to cementum in mutirooted teeth...in tht case it should be gingival fibers right?
 
in glycolysis...net outcome s 2 pyruvate , 2 ATP and 2 NADH....so each NADH will give 3 ATP... so told must be 8 ATP'S and 2 pyruvate coming from glycolysis right?
but in decks they have given as 4 ATP's from 2 NADH...how?
 
thts wht i thought...but like transeptal fibers, interradicular fibers goes from cementum to cementum in mutirooted teeth...in tht case it should be gingival fibers right?

interradicular periodontal fibers run from cementum to the interredicular alveolar bone of multirooted teeth....and therefore the interredicular fibers in one of the subtype of dentogingival group of periodontal fibers or principle periodontal fibers...

where as transeptal fibers run b/n roots of adjecent teeth from cementum to cementum

source: wiki and avery oral histology

correct me if i m wrong
 
in glycolysis...net outcome s 2 pyruvate , 2 ATP and 2 NADH....so each NADH will give 3 ATP... so told must be 8 ATP'S and 2 pyruvate coming from glycolysis right?
but in decks they have given as 4 ATP's from 2 NADH...how?

1 NADH molecule is equal to 2 ATP.
1 FADH2 - 3 ATP.

GLUCOSE TO 2*PIRUVATE = 2 ATP+ 2 NADF = (2+2*2) ATP = 6 ATP
2*PIRUVATE TO 2*ACETYL-CoA = 2 FADH2 = 6 ATP
2*ACETYL-CoA TO 2*Kreb's = 2 ATP + 6 FADH2 + 2 NADH = (2+18+4) ATP = 24ATP
 
thts wht i thought...but like transeptal fibers, interradicular fibers goes from cementum to cementum in mutirooted teeth...in tht case it should be gingival fibers right?

Bifurcational\trifurcational (interradicular) fibers cannot be "gingival"
Transseptal fibers attach gingiva
 
Secretin is secreted from the wall of small intestine in response to acidic chyme... which stimulate carboxypeptidase secretion from Pancreas ...

source: wiki

ya thank u....



muscle for opening mouth with translation?
and without translation?


difference bt pulp chamber,pulp cavity?
 
ya thank u....



muscle for opening mouth with translation?
and without translation?


difference bt pulp chamber,pulp cavity?

Medical Dictionary

pulp chamber definition
Function: n
: the part of the pulp cavity lying in the crown of a tooth
 
What does translation mean in this context? Opening only in saggital plane (without lateral shift or protrusion) or opening+protrusion?:confused:


that was answer choices in 1 of the question....
it is the muscle to open the mouth with translation(wide opening)---lateral pterygoid

without translation (slight opening -jus rotation of the condyle)-is also lateral pterygoid

no protrusion...

correct me if im wrong....
 
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that was answer choices in 1 of the question....
it is the muscle to open the mouth with translation(wide opening)---lateral pterygoid

without translation (slight opening -jus rotation of the condyle)-is also lateral pterygoid

no protrusion...

correct me if im wrong....
Right. Avoiding all the confusion-Lat.Pterygoids are the only muscles acting to open the mandible among the muscles of mastication.Rest all have opposite action.:thumbup:
 
Hi guys, Could someone teach me concept behind blood flow and blood vessels?
Some sources including wikipedia says vasoconstriction (decreased diameter of arteries) can restrict blood flow. I also learned in my class that smaller diameter means less blood flow.

However, one of the old released question says angiotension II can constrict blood vessel resulting in increased blood flow and cause hypertension.

Which one is telling the truth?
 
that was answer choices in 1 of the question....
it is the muscle to open the mouth with translation(wide opening)---lateral pterygoid

without translation (slight opening -jus rotation of the condyle)-is also lateral pterygoid

no protrusion...

correct me if im wrong....

It means condyles translation (not jaw translation)

:confused: Latral pterygoid muscles only assist suprahyiod muscles in opening. I think that lat. pterygoids do not work in slight opening. But I'm not sure.
 
Right. Avoiding all the confusion-Lat.Pterygoids are the only muscles acting to open the mandible among the muscles of mastication.Rest all have opposite action.:thumbup:

I read Q again. It does not say muscles of mastication.
 
Hi guys, Could someone teach me concept behind blood flow and blood vessels?
Some sources including wikipedia says vasoconstriction (decreased diameter of arteries) can restrict blood flow. I also learned in my class that smaller diameter means less blood flow.

However, one of the old released question says angiotension II can constrict blood vessel resulting in increased blood flow and cause hypertension.

Which one is telling the truth?
Angiotensin-2 cause vasoconstriction and a decrease in blood flow,increase in blood pressure.
 
each of the following organism can cross the placenta barrier and infect the neonate in utero EXCEPT one. Which one is the EXCEPTION???

A) Syphilis

B) Rubella

C) HSV-2

D) HIV

D) Rotavirus

Please guys help me out. Thanx :)
 
Which of the following laryngeal muscles is responsible for the abduction of the vocal folds

A) cricothyroid

B) Lateral Cricoarytenoid

C) Posterior Cricoarytenoid

D) Transverse Arytenoid

E) Thyroartenoid


Guys i know both the lateral and Posterior Cricoartenoid abduct the vocal fold so which one will be most appropriate answer.

Thanks guys
 
each of the following organism can cross the placenta barrier and infect the neonate in utero EXCEPT one. Which one is the EXCEPTION???

A) Syphilis

B) Rubella

C) HSV-2

D) HIV

D) Rotavirus

Please guys help me out. Thanx :)

Its Rotavirus.

For the next question-lateral cricoarytenoids-adduct; Posterior cricoarytenoids=primary abductor.:thumbup:
 
Which of the following differentiates mandibular premolars from maxillary premolars? Mandibular premolars

a) have pulp horns of equal size
b) have lingual cusps less developed
c) have crowns tilted to the facial
d) have roots much less round and bifurcated
e) have trapezoidal shaped facial surfaces

Answer is C, but if this were on a test I would have gone with B.

We know that mandibular molar crowns tilt to the lingual, and while the mandibular incisors overall have a facial inclination, their crowns do not, so why would mandibular premolars stick out to the facial by themselves? I also referenced a textbook (Consice Dental Anatomy and Morphology, 3rd ed, Fuller/Denehy) which said mandibular premolar crowns are tilted to the lingual, which they honestly look like too in real life. And, B stood out to me as a better choice because the mandibular 1st premolar definitely has a less developed lingual cusp, even if not the 2nd, whereas the maxillary first L cusp is slightly smaller and the maxillary 2nd is equal height. Altogether, I would say taht overall lingual cusp deficiency is stronger in mandibulars. Please shed some light.
 
u r correct ...in mandibular premolars..... crown show lingual inclination , root show facial inclination ,and lingual cusp are less developed.
 
Which of the following laryngeal muscles is responsible for the abduction of the vocal folds

A) cricothyroid

B) Lateral Cricoarytenoid

C) Posterior Cricoarytenoid

D) Transverse Arytenoid

E) Thyroartenoid


Guys i know both the lateral and Posterior Cricoartenoid abduct the vocal fold so which one will be most appropriate answer.

Thanks guys

It is Posterior Cricoarytenoid. Lateral Cricoarytenoid and Transverse Arytenoid adduct vocal folds.
 
Myoglobin is an oxygen transporting protein in muscle. which amino acid is MOST likely to be on the internal end of the protein???

A) Lysine

B) Aspartate

C)Phenylalanine

D)GLutamate

E) Arginine
 
During periods of moderate exercise, one would expect to see all except?
1. inc CO2 production
2. inc O2 consumption
3. inc pulmonary blood flow
4. inc ventilation rate
5. change in arterial pH.

The correct answer is 5.
I am curious why there is no change in pH.
If CO2 increases (just like choice #1 says), it reacts with water to form H2CO3 (carbonic acid) and then it becomes H and Bicarbonate.
increases in CO2 = increase in H = decrease in pH

When I googled it, it says moderate exercise doesn't change pH whereas sternous exercise does by decreasing the pH. Could someone add more explanation as why it doesn't change in moderate exercise?
 
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During periods of moderate exercise, one would expect to see
1. inc CO2 production
2. inc O2 consumption
3. inc pulmonary blood flow
4. inc ventilation rate
5. change in arterial pH.

The correct answer is 5.
I am curious why there is no change in pH.
If CO2 increases (just like choice #1 says), it reacts with water to form H2CO3 (carbonic acid) and then it becomes H and Bicarbonate.
increases in CO2 = increase in H = decrease in pH

When I googled it, it says moderate exercise doesn't change pH whereas sternous exercise does by decreasing the pH. Could someone add more explanation as why it doesn't change in moderate exercise?
Ok theres some mistake in the question-I think its "except one"?
Then the answer is 5.
Moderate exercise=no change in pH because Acid buffers are produce which resist the change.
Strenuous exercise=Lactic acid produced. pH dips!
 
Apparently nobody could help me understanding this:(

"Can somebody please write down all the contacts occurring in a Laterotrusive mandibular movement. Always confusing!"
 
Myoglobin is an oxygen transporting protein in muscle. which amino acid is MOST likely to be on the internal end of the protein???

A) Lysine

B) Aspartate

C)Phenylalanine

D)GLutamate

E) Arginine

I don't know if this can help you but I found a similar problem.
AA expected to be found on the interior of a globular proteins are leucine and valine. And the reasoning to solve this problem was that these two are nonpolar. I don't know if this gives any clue to solve your problem.

And wikipedia says
"The spherical structure is induced by the protein's tertiary structure. The molecule's apolar (hydrophobic) amino acids are bounded towards the molecule's interior whereas polar (hydrophilic) amino acids are bound outwards, allowing dipole-dipole interactions with the solvent, which explains the molecule's solubility."

One of the website I googled says that the nonpolar AA are
"alanine, cysteine, glycine, isoleucine, leucine, methionine, phenylalanine, proline, tryptophan, tyrosine and valine."
It seems phenylalanine is the only nonpolar AA among the choices so I think phenylalanine is the correct answer.

Did I get it right?

Do I really have to memorize the list of all these AA :(
 
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I don't know if this can help you but I found a similar problem.
AA expected to be found on the interior of a globular proteins are leucine and valine. And the reasoning to solve this problem was that these two are nonpolar. I don't know if this gives any clue to solve your problem.

And wikipedia says
"The spherical structure is induced by the protein's tertiary structure. The molecule's apolar (hydrophobic) amino acids are bounded towards the molecule's interior whereas polar (hydrophilic) amino acids are bound outwards, allowing dipole-dipole interactions with the solvent, which explains the molecule's solubility."

One of the website I googled says that the nonpolar AA are
"alanine, cysteine, glycine, isoleucine, leucine, methionine, phenylalanine, proline, tryptophan, tyrosine and valine."
It seems phenylalanine is the only nonpolar AA among the choices so I think phenylalanine is the correct answer.

Did I get it right?

Do I really have to memorize the list of all these AA :(

thanx
 
Which of the following muscles does not receive its innervation from the buccal branch of the facial nerve

A) Platysma

B) Dilator naris

C) Zygomaticus minor

D) Levator labii superioris

E) Procerus

I know that Platysma is from the cervical branch and Procerus from the temporal branch of the facial nerve. does anyone know how to tackle this or you have a different opinion?????

Thank you all
 
I don't know if this can help you but I found a similar problem.
AA expected to be found on the interior of a globular proteins are leucine and valine. And the reasoning to solve this problem was that these two are nonpolar. I don't know if this gives any clue to solve your problem.

And wikipedia says
"The spherical structure is induced by the protein's tertiary structure. The molecule's apolar (hydrophobic) amino acids are bounded towards the molecule's interior whereas polar (hydrophilic) amino acids are bound outwards, allowing dipole-dipole interactions with the solvent, which explains the molecule's solubility."

One of the website I googled says that the nonpolar AA are
"alanine, cysteine, glycine, isoleucine, leucine, methionine, phenylalanine, proline, tryptophan, tyrosine and valine."
It seems phenylalanine is the only nonpolar AA among the choices so I think phenylalanine is the correct answer.

Did I get it right?

Do I really have to memorize the list of all these AA :(

thanx
 
Which of the following muscles does not receive its innervation from the buccal branch of the facial nerve

A) Platysma

B) Dilator naris

C) Zygomaticus minor

D) Levator labii superioris

E) Procerus

I know that Platysma is from the cervical branch and Procerus from the temporal branch of the facial nerve. does anyone know how to tackle this or you have a different opinion?????

Thank you all

:) no different opinion - it's Platisma
 
Hi,
Here are more questions that I have.

One of the old released test question said
"The lingual cusps of a mandibular 1st molar must be restored to accommodate working movement"

An explanation says
"during left working movement, lingual cusp of left mandibular 1st molar will be involved in chewing"
But I am not sure if this is saying that non working becomes working and then working becomes non working?



My 2nd question is
how does anterior guidance result in vertical and horizontal overlap?
anterior guidance means central incisors are touching tip to tip and none of the posterior teeth are touching.
I don't see any of the vertical and horizontal overlap.


3rd question
Bennett movement influences the mesiodistal position of cusps. Could you explain to me how?
 
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1) 3 days ago, a pt recieved her 3rd immunization with TT ..what class of antibodies specific for TT would one find in her serum?
ans - low concetration of IgM , high conc of IgG

2) which of the factors most influence the lingual concavity of max anterior teeth and groove direction of posterior teeth?
ans- Bennett movement

3)If anticodon on t -RNA is 5'ACG3' thn its corresponding codon on m-RNA is?
ans - 5'CGU3'

CAN ANYONE EXPLAIN ME HOW THESE ANS ARE RIGHT...
 
1) 3 days ago, a pt recieved her 3rd immunization with TT ..what class of antibodies specific for TT would one find in her serum?
ans - low concetration of IgM , high conc of IgG

2) which of the factors most influence the lingual concavity of max anterior teeth and groove direction of posterior teeth?
ans- Bennett movement

3)If anticodon on t -RNA is 5'ACG3' thn its corresponding codon on m-RNA is?
ans - 5'CGU3'

CAN ANYONE EXPLAIN ME HOW THESE ANS ARE RIGHT...

I m not sure with 1 but you are correct with 2 and 3.

2) As far as I understand (I actually studied this about 5 hrs ago :D), you know how posterior teeth have a cusp hitting central fossa...etc? When you are moving it laterally (working; bennett movement), it will move from central fossa to groove(facial groove). For example, distobuccal cusp of mand 1st molar that was hitting the central fossa of max 1st molar is gonna pass the facial groove of max 1st molar, right (m i right?) so it's true that groove direction would be affected by Bennett movement when it comes to posterior.
When it comes to anterior teeth, I am not positive whether i understood this correctly or not but I think mandibular cusps are scretching(i don't know if this is right term LOL:D) the lingual concavity of max teeth.

3) A = T (in DNA replication) or U (when paired into RNA)
G = C (in both DNA and RNA)
5 = 3
FYI, A and T are connected via 2 H bond whereas G and C are connected via 3 H bond so more contents of GC provide more stability and higher melting point.

Now, if you are interested in learning more about Bennett movement, maybe you can answer my question above as well :D

edit: I thnk I might be able to answer 1st one :)
our body got more IgG then any other antibodies followed by IgA.
IgM shows up 1st when you encounter a specific antigen for the very first time.
But if you encounter it for the 2nd time, IgG will show up even faster than IgM.
Since the question said he encountered it for the 3rd time, I think that's what this question was asking and IgG is the correct answer.
 
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1) 3 days ago, a pt recieved her 3rd immunization with TT ..what class of antibodies specific for TT would one find in her serum?
ans - low concetration of IgM , high conc of IgG
.

1st immunization - IgM appears first then IgG (high concetration of IgM , low conc of IgG)
2nd immunization - IgG concentration become higher
3rd immunization - high conc of IgG, low concetration of IgM
 
2) which of the factors most influence the lingual concavity of max anterior teeth and groove direction of posterior teeth?
ans- Bennett movement

3)If anticodon on t -RNA is 5'ACG3' thn its corresponding codon on m-RNA is?
ans - 5'CGU3'.

2) Can you write all answers? I don't think this answer correct:confused: How Bennett movement influens lingual concavity - front teeth are not in occlusion in Bennet movement. What does "groove direction" mean? Grooves move to different directions during Bennet movement, protrusion, etc.

3) Imagine 2 complementary sequences - m-RNA(codon) and t-RNA(anticodon). If one sequence 5'ACG3', complementary sequence UGC. But this complmentary sequence is 3' to 5'. 3' UGC 5' = 5' CGU 3'
 
I don't know where you got this question from (If you don't mind, let me know)but I think answer is B.
C doesn't make sense at all.
Mand 1st molar got lingual cusp size that is only 2/3 of the buccal cusp. Since it's so small, this tooth often has only one pulp horn for buccal and no pulp horn for lingual.
 
I think thats the right answer-about Bennett movement. BM is nothing but the lateral shift. Now if the cusps are steep/long....or lingual fossa/concavity is not wide enough,the harder it is for the mandible to slide through the grooves btw the teeth(in post.teeth) or through the fossa/concavity(in ant.teeth) for the lateral movement to occur! Therefore it has got the greatest influence.
I hope you all got it.:thumbup::p
 
Can someone tell me which one is longer Occluso-cervically between max and mand canine?

1 old exam says max canine is larger than mand in all dimension, but another version says max canine has shorter crown.
 
Can someone tell me which one is longer Occluso-cervically between max and mand canine?

1 old exam says max canine is larger than mand in all dimension, but another version says max canine has shorter crown.

From what I read-overall largest-Max canine but occlusocervically(crown) largest in Mand canine.
 
I think thats the right answer-about Bennett movement. BM is nothing but the lateral shift. Now if the cusps are steep/long....or lingual fossa/concavity is not wide enough,the harder it is for the mandible to slide through the grooves btw the teeth(in post.teeth) or through the fossa/concavity(in ant.teeth) for the lateral movement to occur! Therefore it has got the greatest influence.
I hope you all got it.:thumbup::p

:laugh:I have not . Shape and size of lingual fossa and cusps\grooves influence Bennett movement.
But how movement affects shape of the teeth? "Bennett movement is factor that most influence the lingual concavity of max anterior teeth and groove direction of posterior teeth" :confused:
 
:laugh:I have not . Shape and size of lingual fossa and cusps\grooves influence Bennett movement.
But how movement affects shape of the teeth? "Bennett movement is factor that most influence the lingual concavity of max anterior teeth and groove direction of posterior teeth" :confused:

I guess the framing of the question is messed up here. If its actually asking that then the only answer should be Tooth development!:D:laugh: lame!
 
I guess the framing of the question is messed up here. If its actually asking that then the only answer should be Tooth development!:D:laugh: lame!

yeah i guess so..tooth development option s not there...other options are
1) anterior guidence
2)angle of eminence
3) curve of occlusion
4)direction of movement of rotating condyle
5)Bennett movement (ans)

thankz anyway
 
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