premolar tooth anatomy

ohs final fall 24

what is the outline for for a maxillary first premolar? buccal, proximal and occlusal

buccal: pentagonal/trapezoidal

proximal: trapezoidal

occlusal: hexagonal or oval

on what tooth is the mesiobuccal cusp ridge longer than the distobuccal cusp ridge?

maxillary first premolar

the buccal cusp tip of a maxillary first premolar is offset _____. (mesially/distally)

distally

a maxillary first premolar has two cusps, of which the ____ (lingual/buccal) is shorter.

lingual cusp is shorter

which tooth has a deeper mesial root depression than distal root depression?

maxillary first premolar

what tooth has a mesial marginal developmental groove?

maxillary first premolars are the ONLY teeth with a mesial marginal developmental groove

which crown is larger: maxillary 1st premolar or maxillary 2nd premolar

maxillary 1st premolar

what triangular ridges join to form a transverse ridge on a maxillary 1st premolar?

buccal and lingual triangular ridge

what are the interproximal heights of contour of a maxillary 1st premolar?

mesial: middle third (slightly occlusal)

distal: middle third (slightly occlusal)w

what are the buccal and lingual heights of contour on a maxillary 1st premolar?

buccal: cervical/middle junction

lingual: middle third

how many roots does a maxillary first premolar have?

majority: 2 (buccal and lingual/palatal), sometimes 1 root

always has 2 canals whether its 2 or 1 root

compare root lengths on a maxillary 1st premolar

the buccal root is longer than the palatal root

what is the pulp morphology of a maxillary 1st premolar at a cross-section of the CEJ?

kidney bean, because of the deep mesial root depressionwhat i

what is the endo access shape for maxillary 1st and 2nd premolars?

oval

what are the functional cusps on maxillary teeth?

lingual

in class I occlusion, the buccal cusp of a maxillary 1st premolar occludes with

the embrasure space between the mandibular 1st and 2nd premolars

in class I occlusion, the lingual cusp of a maxillary 1st premolar occludes with

cusp-fossa & cup-marginal ridge

cusp-fossa: L cusp : D fossa of SNOT

cusp-marginal ridge: L cusp : DMR SNOT, MMR 1DOT (tripod)SNOT

SNOT

same named opposite tooth

ex: #4 and #29

1DOT

1 tooth distal to the SNOT

describe the outline form of a maxillary 2nd premolar (buccal, proximal, occlusal)

buccal: pentagonal/trapezoidal

proximal: trapezoidal

occlusal: round/oval

the buccal cusp tip of a maxillary 2nd premolar is offset ____ (mesially/distally)

mesially

compare the length of the buccal and lingual cusps on a maxillary 2nd premolar

buccal cusp = lingual cusp

on a maxillary 2nd premolar, the ____ root has a deeper developmental depression

distal

the occlusal table of a maxillary 2nd premolar has a _____ appearance

wrinkled

what are the interproximal heights of contour on a maxillary 2nd premolar

both mesial and distal: middle third (slightly occlusal)

what are the buccal and lingual heights of contour on a maxillary 2nd premolar

buccal: junction of middle/cervical

lingual: middle third

what premolar has a mesial marginal groove?

maxillary 1st premolar

what tooth in the maxillary arch has the greatest root:crown ratio?

maxillary 2nd premolar (root is 2x the size of the crown)

how many roots does a maxillary 2nd premolar have?

majority: 1 root with 1-2 canals

single, sail-shaped root

what is the pulp morphology of a maxillary 2nd premolar at a cross-section of the CEJ?

oval, wider F-L than M-D

in class I occlusion, the buccal cusp of the maxillary 2nd premolar occludes with

the embrasure space between the SNOT (mand. 2nd PM) and 1DOT (mand. first molar)

in class I occlusion, the lingual cusp of a maxillary 2nd premolar occludes with:

cusp-fossa & cusp-marginal ridge

cusp-fossa: L cusp: D fossa SNOT

cusp-MR: L cusp:DMR SNOT + MMR 1DOT

describe the outline form of a mandibular 1st premolar (facial, proximal, occlusal)

facial: trapezoidal/pentagonal

proximal: rhomboidal

occlusal: diamond shaped

the buccal cusp tip of the mandibular 1st premolar is offset ____ (mesially/distally)

mesially

a mandibular 1st premolar is unique in that it has a _____ developmental groove

mesiolingual

the crowns of a mandibular 1st premolar appear to be tiled ___ relative to their roots

lingually

causes more drastic difference in cusp lengths than mandibular 2nd the me

the mesial marginal ridge of a mandibular 1st premolar has (more/less) inclination towards the cervix than the distal marginal ridge

more

what ridges merge to form a transverse ridge on a mandibular 1st premolar?

buccal and lingual

what is unique about the central groove of a mandibular 1st premolar?

nothing, it doesn’t have one

what are the interproximal heights of contour on a mandibular 1st premolar?

mesial: junction of middle/occlusal

distal: occlusal

on what tooth are the interproximal contacts reversed significantly?

mandibular 1st premolar (mesial contact is more cervical than the distal)

what are the buccal and lingual heights of contour on a mandibular 1st premolar?

buccal: cervical third

lingual: middle third

what tooth has “snake eyes” on its occlusal table?

mandibular 1st premolar

in class I occlusion, the buccal cusp of the mandibular premolars occlude with

cusp-fossa & cusp-marginal ridge

cusp-fossa: B cusp: M fossa SNOT

cusp-MR: B cusp: MMR of SNOT + DMR of 1MOT

(1MOT: 1 tooth anterior/mesial to the SNOT)

how many roots and canals does a mandibular 1st premolar have?

1 root (97.9%), 1 canal (75.8%, 2 canals (24.2%)

1-2 pulp horns, the lingual cusp is sometimes too short

describe the outline form of a mandibular 2nd premolar

facial: trapezoidal/pentagonal

proximal: rhomboidal

occlusal: square or rounded

the buccal cusp tip of a mandibular 2nd premolar is offset ____ (mesially/distally)

mesially

compare the cusp heights of a 3-cusped mandibular 2nd premolar

B>ML>DL

3-cusped mandibular 2nd premolar have a ____ groove between ____ and ____ cusps

L groove between ML/DL cusps

all 3 cusps are visible on from the ____ (mesial/distal) aspect of a mandibular 2nd premolar

distal

what are the interproximal heights of contour of a mandibular 2nd premolar?

mesial and distal: middle

what are the buccal and lingal HOC of a mandibular 2nd premolar?

buccal: cervical third

lingual: middle third

how many roots does a mandibular 2nd premolar have? + what does it look like in a cross section of the CEJ

1 root (99.%)

1 canal (91%), 2 canals (9%)

ovoid shape at CEJ