Well I'm sure about "c" (max canines and 1st pms) but "e"... I can't really say.
Okay if you're still wondering what is being asked in the question, then we'll go easy on it...
1. The first thing asked in the question is about "Prominent developmental grooves"...
2. Second thing given in the question is "Association with embrasure" , (the tooth in the opposite arch will occlude the given embrasure)
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LOGIC
Now if you analyze these two statements, the logic says the presence of development grooves on :-
a. Buccal surface of Maxillary
(Buccal Cusps are guiding cusps, they follow CUSP EMBRASURE occlusion; Posterior Occlusion)
b. Lingual surface of Mandibular.
(Lingual cusps=guiding cusps; follow CUSP EMBRASURE occlusion; Posterior Occlusion)
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Analyze the options now,
a. Embrasure b/w Max CI and LI
It is opposed by Mand. LI, the lingual surface of which never comes in contact with maxillary counterparts (Ant. Occlusion). Even if it was possible (which is not!) the lingual anatomy of mand. LI is indistinct and very rarely a developmental groove is seen.
b. Embrasure b/w max. LI and canine
It is opposed by Mand. Canine, again the lingual surface of this tooth will never come in contact (Ant. Occlusion) and also it has indistinct lingual anatomy. The developmental grooves are rarely found (anyway it has nothing to do with EMBRASURE relationship with max counterpart/s)
c. b/w Max canine and 1st PM
It is opposed by "MAND 1st PM" (Cusp Embrasure relation= Max tooth contacts the embrasure b/w counterpart tooth and one distal tooth)
Now the LINGUAL SURFACE of MAND. 1st PM has a CHARACTERISTIC mesio-LINGUAL GROOVE. (read the LOGIC above again)
You've ONE ANSWER, now.
d. b/w Max 1st and 2nd PM
It is opposed by MAND 2nd PM.
Similar to "c" explanation but it DOES NOT HAVE A CHARACTERISTIC mesio-LINGUAL GROOVE.
e. b/w Mand. canines and 1st PMs
It is opposed by MAX CANINE. Although it doesn't contact the mand counterparts in CENTRIC, the lingual surface of max canine does contact in ECCENTRIC movements (CANINE GUIDANCE) and the lingual anatomy is distinct and a developmental groove may be found.
WELL ONE QUESTION WITH MULTIPLE OPTIONS CORRECT IS NOT THE WAY OF NBDE, you can let rest ALL ENGLISH "FDS RCS" exam pattern.
And if it were on my boards, I'd ONLY marked the OPTION "C"
(Development groove association in centric and eccentric both and characteristic LINGUAL groove present which very common cf. dev. groove found on the lingual surface of MAX CANINE which will participate only in eccentric movements.)
f. b/w Mand 1st and 2nd PMs
It is opposed by Maxillary 1st PM, no characteristic developmental groove seen ( In strictly centric occlusion, the BUCCAL surface of max 1st pm shows no dev. groove)
g. b/w Mand. 2nd PM and 1st Molar
It is opposed by Max 2nd PM, no characteristic developmental groove seen ( In strictly centric occlusion, the BUCCAL surface of max 2nd pm shows no dev. groove)
h. b/w Mand 1st and 2nd Molar.
It is opposed by Maxillary 1st.
Although the buccal groove is present, it is located centrally and doesn't occupy the embrasure, the distobuccal cusp occupies the embrasure and the buccal groove is in association with distobuccal cusp of mand. 1st molar and not embrasure.
So if it were on my NBDE, I would have just marked "OPTION C"
But if multiple options are correct then option "E" is also good but relatively speaking b/w "option C Vs. E" option C rocks my dock.
Mayank. 😀
PS You've just been Neo-maxi-zoom-dweebie-fied !!!
(Enjoy the status for the rest of your lives... 😎)
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DISCLAIMER: I'm not a ready-made encylopedia, nor I'm God, nor do I guarantee my answers. I make mistakes like we all do. Well if everybody else doesn't make mistakes, I'm happy that I do. In all my senses, I suggest everyone to use their brain before they accept any concept/fact.
Regards,
Mayank.
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