Pre Molars

Question 1

Upper right first premolar identification markers?

Answer 1

More than 50% have two roots (one buccal other palatal) - root decision (bifurcation)
Root can sometimes have very fused roots
Looks like canine from buccal view
Crown = distal very convex and mesial slightly convex but root = canine fossa ( cervical half mesial concave in between roots ) present as of mesiodistal flatness of canine
Palatal surface narrower and lower than buccal
Also buccal cusp wider and higher

Of occlusal surface:
Two cusps separated by U shaped fissure that doesn’t cut distal marginal ridge and then has groove that also cuts through mesial marginal ridge in line with canine fossa ( a developmental depression )
Roughly oval

Mesial displacement of lingual cusp
Distal marginal ridge more cervical that mesial
Always wide and flat pulp with shape of root and two horns

Question 2

Upper right second premolar identification markers?

Answer 2

Smaller than upper first
Single root with no bifurcation but can see outline of two roots (only 15% have 2)
Buccal cusp reduced = similar width and height of both cusps
No groove through mesial marginal ridge and convex mesial crown
Slight mesial displacement of lingual cusp (less than first)
Distal marginal ridge more cervical
Same fissure except stays within ridges
Root compressed mesiodistally
Pulp generally not deprecated into horns

Question 3

Lower right first premolar identification markers?

Answer 3

Buccal surface greatly inclined lingually
Lingual cusp extremely lower and slightly narrower than buccal and displaced distally
Occlusal surface almost round like canine
Small groove runs from mesial pit to the mesiolingual surface
ONLY of the 4 premolar types to have marginal ridge more cervical on mesial side (as groove pulls marginal ridge down)
Mesial side of oclusal surface less flat and more bulged to make short and flat contact point for canine
Contact point more buccally at mesial side compared to distal
Often root grooved mesially and distally
Usually one pulp horn and pulp compressed mesiodistally

Question 4

Lower right second premolar identification markers?

Answer 4

Larger crown and larger lingual cusp than first (also displaced mesially
May have two lingual cusps ( mesial larger )
Distal fossa generally larger than mesial
Distal marginal ridge more cervical
Single root
More circular root than first lower and stronger
Pulp cavity only slightly compressed mesiodistally

Question 5

Lower and upper differences

Answer 5

Lower more circular and upper more oval