DA Q's from Rel. 96

[32pearls]

Hi everybody,
I have a few doubts from some q's in DA .Hope somebody can answer.

1. In an ideal intercuspal relation,lingual cusp of max. 2nd premolar contact
A. distal fossa of mandibular 2nd pm
B. MMR of mand. 1st molar
C. DMR of mand. 2nd molar
D. DMR of mandibular 1st premolar

I feel the ans. to this is D.- DMR of mand. 1 pm [according to notes of Kaplan], but in the ASDA ans. key its given as A.
In the Kaplan explanation for the same question they are saying it is D. eventhough they mixed up the expln. by saying "DMR of mandibular 2nd premolar or MMR of mandibular 1 molar"- [this could be a typing mistake eventhough I noticed more mistakes]

2. On non-working side in an ideal occlusion,interfering contacts on posterior teeth will be located on which inclines of which cusps?
Inclines Cusps
A. Outer Guiding
B. Inner Guiding
C. Outer Supporting
D. Inner Supporting

Can anyone plz explain this one?

3. Which is characteristic of primary maxillary canine?
A. crown height < mesial-distal width
B. cusp is lower & rounded
C. mesial-incisal cusp ridge shorter than disto-incisal
D. mesial-incisal cusp ridge longer than disto-incisal


I feel its ans. is D. and in ASDA key it says D. But Kaplan expln says it could be both A. & D.
How can this be possible?According to wheelers crown ht of max. primary canine is 6.5 mm while its mes-dis width is 7 mm

Now I'm kinda confused with Kaplan explanations,can we really rely on it?

Hope someone will be kind enough to answer these.
Thanks

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[Ibanez]

Hi everybody,
I have a few doubts from some q's in DA .Hope somebody can answer.

1. In an ideal intercuspal relation,lingual cusp of max. 2nd premolar contact

The answer is A.

In simplest of terms, I give you the RULES for posterior contact relations...

RULE 1:

The BUCCAL cusps of MAX PREMOLARS follow CUSP EMBRASURE RELATIONSHIP with mandibular counterparts (1 mand. tooth with 2 max. teeth)

RULE 2:

The LINGUAL cusps of MAX PREMOLARS follow CUSP FOSSA relationship with mandibular counterpart (these supporting cusp contacts DISTAL FOSSA of mandibular counterpart; "1 tooth contacting 1 tooth")

RULE 3:

BULL NEVER Works: Buccal-upper; Lingual-lower --> BALANCING side contacts (mediotrusive contacts) follow CUSP EMBRASURE relationship.

RULE 4:

WORKING/SUPPORTING CUSPS (Maxillary= Palatal/Lingual; Mandibular= Facial/Buccal) follow CUSP FOSSA relationship

RULE 5:

MAXILLARY SUPPORTING/WORKING CUSPS (Lingual/Palatal) contacts DISTAL FOSSA of the mandibular counterpart

*Exception:
Mesio-lingual cusp of max molars contacts CENTRAL FOSSA (and not distal fossa) of mandibular counterpart.

RULE 6:

MANDIBULAR SUPPORTING/WORKING CUSPS (Buccal/Facial) contacts MESIAL FOSSA of maxillary counterpart.

*Exception:
1. Disto-buccal cusp of mandibular molars contact CENTRAL FOSSA of max counterpart.
2. Distal cusp of mand. 1st molar contacts DISTAL FOSSA

RULE 7:

MESIO-LINGUAL CUSP of MAXILLARY first/second molar contacts CENTRAL FOSSA of mandibular first/second molar.

RULE 8:

DISTO-BUCCAL CUSP of MANDIBULAR first/second molar contacts CENTRAL FOSSA of maxillary first/second molar

RULE 9:

I love making sad attepmts at being Jackass (var. Jhak-as; read)

---> Applying Rule 2,4,5 ; the maxillary 2nd premolar contacts Distal fossa of mandibular 2nd premolar.


2. On non-working side in an ideal occlusion,interfering contacts on posterior teeth will be located on which inclines of which cusps?
Inclines Cusps

Can anyone plz explain this one?

The answer is D.

The non-working/cross-arch-balanced contact relation occurs between the BUCCAL incline of Maxillary Palatal/Lingual cusp and LINGUAL incline of Mandibular Buccal cusp.

--> INNER SUPPORTING
(I presumed that inner inclines are relative to individual tooth)




3. Which is characteristic of primary maxillary canine?
A. crown height < mesial-distal width

D. mesial-incisal cusp ridge longer than disto-incisal

The answer is D.

Well the "CHARACTERISTIC" feature of primary max canine is Mesial Incisal cusp ridge (cf. crown height < M-D width)

1.All maxillary primary teeth (except primary max LI) have crown height < M-D width.

2. If you have to identify primary max canine RIGHT Vs. LEFT, the MESIAL INCISAL RIDGE is the key and not crown height Vs. M-D width.



Your hope has been answered, my friend!

If you still have any doubt (God! Have mercy on my soul )... buzz me!

Nevermind,
Mayank.


PS Never apply rule 9

 

[32pearls]

Hi Ibanez,
Awesome job!!! I really appreciate the way u answered my "hope"! Thanks for ur time. I'm sure this will be useful to all who go thru this thread.
I will post more questions soon.
Thanks again!

 

[Ibanez]

You're welcome, anytime.

 

[fairy123]

hi everyone
if sombody knows the exact ans of these dental anatomy ques,
1-Which of the following anatomic features of a maxillary lateral incisors will most likely complicate root planning?

A-root convexity
B-mesial concavity
C-distolingual groove
D-root bifurcation
E-extremedistal cervical line curvature.

ans in key is B,

2-in a protusive movement,the contacting surfaces of the incisors are

A- the lingual of the mandibular and the incisal edge of the maxillary
B-the facial of the maxillary and the incisal edge of the mandibular
C-the lingual of the maxillary and the incisal edge of the mandibuar
D-the facial of the mandibular and the incisal edge of the maxillary

ans in key is C

3-which of the following teeth is most likely to exhibit 3 pulp canals?

A-tooth#4
B-tooth#12
C-tooth#20
D-tooth#27

ans in key is B

4-which of teh following describes the contact relationship between a maxillary central incisor and a maxillary lateral incisors?

A-contact is offset to the lingual
B-contact is centered incisocervically
C-lingual embrassure is larger than the facial embrassure
D-incisal embrassure is the largest of all the embrassure

in one ques paper the ans key is A
n in pilot2004 ans is C
what is the exact ans?

 

[Ibanez]

1-Which of the following anatomic features of a maxillary lateral incisors will most likely complicate root planning?

A-root convexity
B-mesial concavity
C-distolingual groove
D-root bifurcation
E-extremedistal cervical line curvature.

B or C?
C, it is.

--> Root CONCAVITY and RADICULAR GROOVES are absolute HINDERANCE to ROOT PLANING.

--> If the radicular grooves are DEEP into the pulp, it will "COMPLICATE" root planing . Even if they are not, they are still a predisposing factor for periodontal disease.
A flap is raised in such situations for root planing.

--> Root CONCAVITY will result in incomplete root planing (Nidus for bacterial growth; accelerated periodontal disease)

Radicular grooves are more complicating than mesial concavity...
So the answer is C.





2-in a protusive movement,the contacting surfaces of the incisors are

A- the lingual of the mandibular and the incisal edge of the maxillary
B-the facial of the maxillary and the incisal edge of the mandibular
C-the lingual of the maxillary and the incisal edge of the mandibuar
D-the facial of the mandibular and the incisal edge of the maxillary

The answer is C.

This is known as INCISAL GUIDANCE. In a group function occlusion (/mutually protected occlusion; Ideal) the lingual slope of maxillary Incisors GUIDE the mandible during protrusion (the incisal edge of mandibular incisors traverse the slope of maxillary incisors during protrusion.)




3-which of the following teeth is most likely to exhibit 3 pulp canals?

A-tooth#4
B-tooth#12
C-tooth#20
D-tooth#27

The answer is B.

#12 is Max. Lt. 1st Premolar (two roots MC, sometimes single
#4 is Max Rt. 2nd Premolar (single root; Root canals: 1 MC in Caucasians and 2 MC in negros; 3 rarley)
#20 is Mand. 2nd premolar (single root; root canal: 1 MC, 2... 3 very rarely)
#27 is Mand. Rt. canine (single root; single canal MC)

MC=most common



4-which of teh following describes the contact relationship between a maxillary central incisor and a maxillary lateral incisors?

A-contact is offset to the lingual
B-contact is centered incisocervically
C-lingual embrassure is larger than the facial embrassure
D-incisal embrassure is the largest of all the embrassure


The answer is C.

Generally LINGUAL EMBRASURE > FACIAL;

EXCEPTION: Maxillary molars and mandibular anteriors (F>L)

Contact is in the center of labio-lingual diameter and not lingual.


PS I'm done with my daily SDN dose! Whoof!

 

[fairy123]

thanks a loooooottt

 

[Ibanez]

thanks a loooooottt

You're welcome.

Mayank.

 

[seeundbe]

Q . Which of the following marginal ridges have little or no contact in ideal centric & ecentrc maxilomand contact relationship
1 D to Max 2 PM
2 D to mand 1PM
3 D to mand 2PM
4 M to max canine
5 M to mand 1PM

1 - 1, 2
2 - 1 , 4
3 - 2, 3, 4
4 - 2, 3, 5
5 - 4, 5
please explain this

 

[Ibanez]

Q . Which of the following marginal ridges have little or no contact in ideal centric & ecentrc maxilomand contact relationship
1 D to Max 2 PM
2 D to mand 1PM
3 D to mand 2PM
4 M to max canine
5 M to mand 1PM

1 - 1, 2
2 - 1 , 4
3 - 2, 3, 4
4 - 2, 3, 5
5 - 4, 5


1. Option 5 sounds true to me according to the question (centric + eccentric); MMR of mand 1st premolar. The MMR of mand 1st is opposed by lingual surface max canine, but does not contact (Ant. Occlusion/ Mutually protected)

2. The DMR of mand premolars of does come in contact with max counterpart in CENTRIC (but how intimately they are in contact... I don't know. Maybe a "little") but during eccentric I think they are not in contact (Mutually protected Occlusion).

The DISTAL MARGINAL RIDGE of mand 1st PM is higher but still I don't think has much contact in centric. So maybe yes...



3. Also, MMR of Max Canine will have NO contact in CENTRIC but will definitely come in intimate contact during lateral eccentric (/Canine Guidance)

Since MMR of mand 1st premolar stands 100% good, and I almost sure about DMR also... the only available options left is Option 4 (2,3,5) but I'm not quite sure.




Mayank.