help on questions in part 2 papers

[dentalfloss]

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hi everyone,
I had a few qs in some papers, the answers to which I am not sure of. Pls help me:
1) Using B speed film, exposure to the patient at 3 feet is 1Roentgen.What would the exposure be with a D speed film at 6 feet? (Assuming all other exposure factors to be the same)
1) 1/8R
2) 1/4R
3) 1/2R
4) 3/4R
Is there a formula to calculate this?

2) Which is the most commonly overretained primary tooth?
1) Mandibular 1st molar
2) Maxillary 1st molar
3) Maxillary 2nd molar
4) Mandibular 2nd molar

The answer to the 2nd q as per dental decks is 1- Mandi 1st molar. But I was thinking it is mandibular 2nd molar, right? since the mandibular 2nd molar is the one mostly ankylosed too..and also the mandibular 2nd premolar is the one more commonly missing.
Pls help me with these qs.
Thanks

 

[kaukam]

hi everyone,
I had a few qs in some papers, the answers to which I am not sure of. Pls help me:
1) Using B speed film, exposure to the patient at 3 feet is 1Roentgen.What would the exposure be with a D speed film at 6 feet? (Assuming all other exposure factors to be the same)
1) 1/8R
2) 1/4R
3) 1/2R
4) 3/4R
Is there a formula to calculate this?

2) Which is the most commonly overretained primary tooth?
1) Mandibular 1st molar
2) Maxillary 1st molar
3) Maxillary 2nd molar
4) Mandibular 2nd molar

The answer to the 2nd q as per dental decks is 1- Mandi 1st molar. But I was thinking it is mandibular 2nd molar, right? since the mandibular 2nd molar is the one mostly ankylosed too..and also the mandibular 2nd premolar is the one more commonly missing.
Pls help me with these qs.
Thanks

Considering A, B, C, D, E, F films exposure required for B is half that of A, and that for C is half that B ..... so on.



therefore exposure of D film is 1/4 of B film



T a D2
Kvp X mA


When all the factors remain constant,
a) exposure time is inversly proportional to milliamperage and KVP
b) directly proportional to the square of anode-film (target film) distance


In this question distance is doubled, the exposure time should be increased by four times.

therefore the answer should be 1R only ( 1/4 X4=1)

 

[vaish]

Which one is depressed first by LA.
(1) small unmyelinated fibre
(2) small myelinated fibre.

In decks ,in one card it is myelinated and in one card it is unmyelinated.

Plz help which one is the right answer.

 

[kaukam]

sorry friends I was giving explnation to the exposure time . I would like to correct my explanation as follows

Considering A, B, C, D, E, F films exposure required for B is half that of A, and that for C is half that B ..... so on.



therefore exposure of D film is 1/4 of B film



intensity of radiation is inversly proportional of the square of the distances. So in the question if distance is doubled the radiation decreases by 4 times or it becomes 1/4R .

we see in the first statement that D film exposure is 1/4 of B film , then answer should be 1/4 X 1/4= 1/16R

 

[kaukam]

The answer for second question is primary mandibular second molar

 

[kaukam]

Which one is depressed first by LA.
(1) small unmyelinated fibre
(2) small myelinated fibre.

In decks ,in one card it is myelinated and in one card it is unmyelinated.

Plz help which one is the right answer.

unmyelinated nerve fibres

 

[WenChen]

look at the correction at deck corp.

Dental Decks Part II 2007 - 2008 Edition

Section: Oral Surgery
Category: Anesth
Card: Local anesthetics stop axonal conduction by blocking:

Correction: On the back of the card the paragraph that begins with Important: should read as follows (the correction is in red):

Important: Small, nonmyelinated nerve fibers which conduct pain and temperature sensations, are affected first, followed by touch, proprioception, and skeletal muscle tone.

Which one is depressed first by LA.
(1) small unmyelinated fibre
(2) small myelinated fibre.

In decks ,in one card it is myelinated and in one card it is unmyelinated.

Plz help which one is the right answer.

 

[WenChen]

according to my textbook Oral & Maxillofacial pathology 2nd ed. by Nevelle,
they state primary mandibular 1st molar is the most commonly ankylosis tooth

hi everyone,
I had a few qs in some papers, the answers to which I am not sure of. Pls help me:
1) Using B speed film, exposure to the patient at 3 feet is 1Roentgen.What would the exposure be with a D speed film at 6 feet? (Assuming all other exposure factors to be the same)
1) 1/8R
2) 1/4R
3) 1/2R
4) 3/4R
Is there a formula to calculate this?

2) Which is the most commonly overretained primary tooth?
1) Mandibular 1st molar
2) Maxillary 1st molar
3) Maxillary 2nd molar
4) Mandibular 2nd molar

The answer to the 2nd q as per dental decks is 1- Mandi 1st molar. But I was thinking it is mandibular 2nd molar, right? since the mandibular 2nd molar is the one mostly ankylosed too..and also the mandibular 2nd premolar is the one more commonly missing.
Pls help me with these qs.
Thanks

 

[dentalfloss]

Thank you Kaukam, But the answer is 1/8R.

 

[dentalfloss]

You are right wenchen.. .The most commonly ankylosed tooth is Mandi 1st molar. I was wrong, I guess. I have'nt figured how the answer to my 1st q is 1/8R though.