Lecture 6 - Maxillary Premolars Flashcards
what are the numbers of the maxillary right first and second premolar
1st- #5
2nd - #4
what are the numbers of the maxillary left first and second premolars
1st- #12
2nd- #13
what are the 2 cusps on the maxillary premolars and describe each
lingual - functional cusp
buccal - non-functional cusp
are premolars succedaneous teeth
yes they replace deciduous molar teeth
what are the lobes of the maxillary first premolars
-3 buccal lobes ( mesial buccal, middle, and distobuccal)
- 1 lingual lobe - develops into the lingual cusp
what does the buccal cusp develop from on maxillary first premolars
the middle buccal lobe
what is the central developmental groove on maxillary first premolars
a demarcation between the lingual and buccal lobes
describe the shape of the maxillary first premolar from the buccal view
roughly trapezoidal
describe the buccal cusp arms (M vs D) of the maxillary first premolars
-mesial cusp arm is longer and straighter
- distal cusp arm is shorter and more curved
where is the buccal height of contour of the maxillary first premolars
in the cervical third
where is the mesial contact of the maxillary first premolars
middle 1/3rd
describe the mesial outline from the facial view of the maxillary first premolars
mesial concavity below the contact
where is the distal contact of the maxillary first premolar
middle 1/3rd, larger contact (broader) and more cervical
describe the distal outline of the maxillary first premolar from the facial view
generally convex
describe the lobes/ridges on the buccal view of the maxillary first premolars
-middle buccal lobe -> prominent buccal ridge and associated developmental depressions
- less developed mesial and distal lobes -> mesial and distal line angles
which direction does the crown taper of the maxillary first premolars
lingually
- lingual is more narrow than buccal
describe the lingual cusp of the maxillary first premolars
-smoothly convex
- 1 mm shorter than buccal cusp and more pointed
where is the lingual cusp located of the maxillary first premolars
mesially
describe the lingual cusp arms (M vs D) of the maxillary first premolars
mesiolingual cusp arm is shorter than the distolingual cusp arm
what is the shape of the maxillary first premolar from the mesial view
trapezoidal
what cusps are visible from the mesial view of the maxillary first premolars
both lingual and buccal
where is the buccal height of contour of the maxillary first premolars
cervical 1/3
where is the lingual height of contour of the maxillary first premolars
middle 1/3
what depressions are visible from the mesial view of the maxillary first premolars
developmental depression on the cervical portion of the crown and the root
where is the mesial contact area for the maxillary first premolar from the mesial view
middle 1/3 and offset buccally
how many roots do maxillary first premolars have
- 50-60% have 2 roots (buccal and lingual)
- 50% have 1 root
how long is the root trunk of the maxillary first premolars
1/2-2/3 the length of the root
what are the differences between the distal view and the mesial view of the maxillary first premolars
-distal view does not have concavity, developmental depreesion, or marginal ridge developmental groove
- curvature of CEJ is less
where is the distal contact area from the distal view of the maxillary first premolars
middle 1/3
-offset buccally
-contact borader
- located more cervical than mesial
describe shape of the the maxillary first premolars from the occlusal view
hexagonal in outline
which dimension is the maxillary first premolars larger in from occlusal view: BL or MD
BL > MD
how many ridges make up each cusp on the maxillary first premolars
4 ridges each
where is the buccal triangular ridge of the maxillary first premolars located from the occlusal view
from the central developmental groove to the middle cusp
where is the lingual triangular ridge of the maxillary first premolars located from the occlusal view
from the central developmental groove to the lingual cusp
what is the difference between the buccal and lingual triangular ridges from the occlusal view of the maxillary first premolars
lingual less prominent and angled not straight
what is a triangular ridge
prominent elevation, triangular in cross-section, which extends from the tip of a cusp towards the central portion of the occlusal surface of a tooth
what ridges are visible from the maxillary first premolars occlusal view
- mesial and distal marginal ridges
what grooves are visible from the maxillary first premolars occlusal view
-central developmental groove
- mesial marginal ridge developmental groove
- mesiobuccal and distobuccal supplemental groove
what pits and fossa are visible from the maxillary first premolars occlusal view
mesial and distal developmental pits
mesial and distal triangular fossa
what does the root from the buccal (MD) aspect of the maxillary first premolar resemble
the root of the canine
describe the root of the maxillary first premolar in cross section
broad BL, narrow MD
- kidney shaped
- mesial developmental depression
how many pulp horns and pulp canals are there in the maxillary first premolar
2 pulp horns and 2 pulp canals ( buccal is larger canal)
what is a distinct feature to help identify the maxillary first premolar
the mesial marginal ridge developmental groove on the occlusal surface
what are the main differences between the maxillary first premolar and the maxillary second premolar
- smaller
- more rounded
- single rooted
- more shape variations
what are the differences from the buccal view from the maxillary first premolar and the maxillary second premolar
- MB and DB line angles are less prominent
- buccal cusp ridge not as obvious
- buccal developmental depressions not as developed
compare the MB cusp arm to DB cusp arm of the maxillary second premolar from the buccal view
MB cusp arm is shorter than the DB cusp arm
what is the difference between the lingual view of the maxillary first premolar and the maxillary second premolar
lingual cusp is longer in the second premolar so less visibility of the buccal cusp lingually
describe the buccal and lingual cusps of the maxillary second premolar from the mesial view
buccal and lingual cusps are approximately equal in size but shorter compared to first premolar
where is the mesial contact from the mesial view of the maxillary second premolar
middle 1/3 and slightly offset buccally
describe the mesial view of the maxillary second premolar
no mesial marginal ridge developmental groove
no mesial developmental depression
single tapered root
where is the distal contact from the distal view of the maxillary second premolar
middle 1/3 and offset to the buccal
what shape is the maxillary second premolar from the occlusal view
rounded or oval
describe the MB and DB line angles of the maxillary second premolar from the occlusal view
more rounded
describe the central developmental groove of the maxillary second premolar from the occlusal view
central developmental groove is shorter therefore, mesial and distal marginal ridges are wider
describe the supplemental grooves of the maxillary second premolar from the occlusal view
numerous supplemental grooves - wrinkled appearance
describe the root of the second premolar
-single tapered root 50% have two canals
- root length the same as first premolar
broad BL, narrow MD
- no developmental depression
- oval shaped in cross section
how many pulp horns and canals do the maxillary second premolar have
two pulp horns and 50% have two canals
where is the mesial height of contour of the maxillary second premolar
middle third
where is the distal height of contour of the maxillary second premolar
middle third
where is the buccal height of contour of the maxillary second premolar
cervical third
where is the lingual height of contour of the maxillary second premolar
middle third
when does the maxillary first premolar erupt
10-11 years
when does the maxillary second premolar
11-12 years
describe the cervico- occlusal length of the maxillary first premolar crown vs the maxillary second premolar crown
same length
describe the MD diameter of crown of the maxillary first premolar crown vs the maxillary second premolar crown
same
describe the root length of the maxillary first premolar vs the maxillary second premolar
same