# Buccal surface of posterior teeth are wider than lingual surface mesiodistally except in:

# Buccal surface of posterior teeth are wider than lingual surface mesiodistally except in:
a) Maxillary second premolar
b) Mandibular second premolar
c) Maxillary first molar
d) Mandibular first molar

The correct answer is C. Maxillary First Molar. 

A measurement of the crown buccolingually and mesial to the buccal and lingual grooves is greater than the measurement on the portion of the crown that is distal to these developmental grooves. Also, a measurement of the crown immediately lingual to contact areas mesiodistally is greater than the measurement immediately buccal to the contact areas. Thus, it is apparent that the maxillary first molar crown is wider mesially than distally and wider lingually than buccally.

Reference:  WHEELER’S Dental Anatomy, Physiology, and Occlusion, 10th Edition, Page 172