Differences between occlusal surface of first permanent molar with second perman!
Question:
Differences between occlusal surface of first permanent molar with second permanent molar?
dental anatomy
Answers:
maxillary(upper) 1st molar- it has 4 cusps in all, with a rhomboidal outline and an accessory tubercle(tubercle of carebelli) to the mesio-lingual side. the cusp sizes are in the order- '(ML)>(MB)>(DL)>(DB)' -. the oblique ridge formed by the triangular ridge of the mesiolinguall and distobuccal cusps is the charecteristic feature.
maxillary 2nd-similar to 1st in shape and no. of cusps, but is slightly smaller. no tubercle is seen. more supplemental grooves are found on the occlusal surface.
mandibular(lower) 1st- hexagonal outline, 5cusps(1st 4 are major). the order in size is 'MB>ML>DL>distal'. the mesio-distal diameter is more than facio-lingual. developmental grooves are-central, mesiobuccal, distobuccal and lingual.
mandibular 2nd-rectangular in outline, 4 cusps. small distal cusp is absent. no distobuccal developmental groove. the buccal and lingual grooves meet central groove at right angles to form a cross and divide the occlusal surface in 4 roughly equal parts. the cusp sequence in terms of size is MB>ML>DL>DB.
key-MB(mesiobuccal),DB(distobu...