03 molar morphology

Question 1

how many pulp horns are present in the maxillary 1st molar?

Answer 1

four (MB, ML, DB and P)

Question 2

what is the shape of the pulp in max 1st molar?

Answer 2

triangular to rhomboid

Question 3

which root of the max 1st m usually has two canals and what is the %?

Answer 3

MB, 70-95%

Question 4

what is the shape of the MB root of the max 1 m?

Answer 4

wide b-l and has a concavity on distal

Question 5

shape of P root of max 1 m

Answer 5

wide M-D, curves to the buccal in apical third

Question 6

“two roots with two canals is not uncommon-8% have only B and P canals”

Answer 6

max 2 m

Question 7

does max 2 m have two roots in the MB root?

Answer 7

yes, but a lower incidence

Question 8

how many roots and canals for mand 1 m?

Answer 8

usually has two roots but can have three
2 canals 6-7%
3 canals 64% (weine type III about 60%)
4 canals 29% (weine type III about 39%)

Question 9

what is the shape of the pulp chamber floor for the mand 1 m?

Answer 9

trapezoid

Question 10

how many pulp horns in mand 1st m?

Answer 10

four (MB, ML, DB, AND DL)

Question 11

compare 1st and 2nd mand m

Answer 11

pulp chamber for 2nd is similar to 1st, but slightly smaller and more compressed,
-lower incidence of 2nd distal canal relative to 1st

Question 12

third molars

Answer 12

anywhere from 1-4 roots with 1-6 root canals

Question 13

“C” shaped canals

Answer 13

mandibular second molar, but sometimes in mand first molar, max 1st and 2nd molars and mand first pm

Question 14

what is the root canal system of a C shaped canal?

Answer 14

single, ribbon-shaped orifice with an arc of 180 degrees or more

Question 15

which law state: “the floor of the pulp chamber is always located in the center of the tooth at the level of the CEJ”

Answer 15

Law of Centrality

Question 16

“the walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ, that is, the external root surface anatomy reflects the internal pulp chamber anatomy”

Answer 16

Law of Concentricity

Question 17

except for the maxillary molars, canal orifices are equidistant from a line drawn in a MD direction through the center of the pulp chamber floor

Answer 17

first law of symmetry

Question 18

except for max molars, canal orifices lie on a line perpendicular to a line drawn in a mesiodistal direction across the center of the pulp chamber floor

Answer 18

second law of symmetry

Question 19

law of color change

Answer 19

the pulp chamber floor is always darker in color than the walls

Question 20

law of orifice location:

Answer 20

the orifices of the root canals are always located at the junction of the walls and the floor