pls anyone answer this question?

[molar747]

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A 36 year patient presents with an ideal class 1 occlusion. The dentist asks the patient to go to maximum intercuspation from left lateral relation. The cusp that moves between the buccal cusps of tooth # 2 is

-distobuccal cusp of # 30
-distal cusp of # 30
-mesiobuccal cusp of # 32
-distobuccal cusp of # 31
-mesiobuccal cusp of # 31

The answer is distobuccal cusp of # 31, however I don't think so. Pls answer with an explanation. Thnx!

 

[Contach]

Whenever you do a question like this, you should draw out this diagram. Do it on every occlusion test, and every dental board exam you take from here on out.

http://usafdds.blogspot.ca/p/q.html

Left lateral relation is when the mandible is swung to the left. When you go from left lateral relation to centric, your distobucal cusp of #31 will go through the lingual groove of #2. No cusp will pass through the buccal groove of #2. The question is wrong, or there must be a typo because there is no correct answer.

 

[molar747]

Whenever you do a question like this, you should draw out this diagram. Do it on every occlusion test, and every dental board exam you take from here on out.

http://usafdds.blogspot.ca/p/q.html

Left lateral relation is when the mandible is swung to the left. When you go from left lateral relation to centric, your distobucal cusp of #31 will go through the lingual groove of #2. No cusp will pass through the buccal groove of #2. The question is wrong, or there must be a typo because there is no correct answer.

Great tips and blog. Thanks, much appreciate it.

 

[sgv]

1. Mandibular premolars's buccal cusp and molars's mesiobuccal cusp hit the maxillary marginal ridges.

2. Mandibular distobuccal cusp hit the central fossa (appearing between the mesiobuccal and distobuccal cusps of maxillary molars during lateral excursion).

3. Mandibular teeth are slightly more mesial in position to opposing maxillary teeth
(Distal ridge of mandibular 1st premolar's buccal cusp would hit the mesial marginal ridge of maxillary 1st premolar reflecting the more mesial position of mandibular teeth)

Also i'm reading this question as if the patient starts in lateral excursion from the observing dentist's left (patient's right) and ends at maximum intercuspation. It seems like a poorly worded question because it doesn't use the patient's anatomical position but the only choice that could make sense is distobuccal cusp of 31.