MDS AIPGDEE preparations B-IDS | mesiolingual cusp of the maxillary third molar MCQ

In centric occlusion, the mesiolingual cusp of the maxillary third molar will contact:
a. the central fossa of the mandibular second molar
b. the central fossa of the mandibular third molar
c. the distal marginal ridge of the mandibular first molar and mesial marginal ridge of the second molar
d. the distal marginal ridge of the mandibular second molar and mesial marginal ridge of the third molar

Ans. B. The mesiolingual cusp of a maxillary third molar is a holding cusp. The general rule for maxillary holding cusps is as follows: a maxillary holding cusp contacts the distal marginal ridge of its mandibular counterpart and the mesial marginal ridge of the mandibular tooth distal to its counterpart, 

EXCEPT FOR THE MESIOLINGUAL CUSPS OF THE MOLARS,

WHICH CONTACT THE CENTRAL FOSSAE OF THEIR COUNTERPARTS, should be the central fossa of the counterpart, the mandibular third molar