Lecture 7 - Mandibular Premolars Flashcards
what are the numbers of mandibular premolars on the left
1st- #21
2nd - #20
what are the numbers of the mandibular premolars on the right
1st- #28
2nd - #29
are mandibular premolars succedaneous teeth
yes they replace primary molars
how many lobes do mandibular first premolars develop from
3 facial
1 lingual
how many lobes do second premolars develop from
3 facial
1 or 2 lingual
what is the shape of the mandibular first premolar from the buccal view
trapezoidal
what does the buccal ridge on the mandibular first premolar develop from
the middle buccal lobe
what does the buccal cusp of the mandibular first premolar resemble
mandibular canine but tip is more rounded
describe the mesiobuccal cusp arm and distobuccal cusp arm on the mandibular first premolar
mesial is shorter than distal
describe the mesial and distal outlines from the buccal view of the mandibular first premolar
slightly concave
where are the mesial and distal heights of contour of the mandibular first premolar from the buccal view
middle 1/3
describe the cervical line from the buccal view of the mandibular first premolar
exhibits little curvature
describe the buccal surface of the mandibular first premolar
convex, especially in the middle and cervical third
describe the root of the mandibular first premolar from the buccal view compared to the mandibular canine
3-4 mm shorter and curves distally
where do the crown and root taper of the mandibular first premolar
toward lingual
describe the lingual cusp of the mandibular first premolar
small, may resemble the cingulum of a canine
describe the occlusal surface of the mandibular first premolar from the lingual view
slopes lingually in a cervical direction, visible from lingual view
describe the lingual view of the mandibular first premolar
- convex
- mesial and distal outlines are concave from the cervical margin to the contact areas
what does the mesiolingual developmental groove mark on the mandibular first premolar
demarcates the lingual lobe from the mesiobuccal lobe
- separates mesial marginal ridge from lingual cusp
what aspects of the mandibular first premolar are visible from the lingual view
the lingual, mesial, and distal aspects are visible
describe the root from the lingual view
-tapers to a pointed apex
- developmental depressions or grooves mesially on the root
what is the shape of the mandibular first premolar from the mesial view
rhomboidal in outline
describe the buccal outline of the mandibular first premolar from the mesial view
very convex
where does the buccal cusp tip lie in relation to a line bisecting the midline of the root of the mandibular first premolar from the mesial view
centered on the line
where is the buccal height of contour of the mandibular first premolar from the mesial view
junction of the middle and cervical 1/3
describe the lingual outline of the mandibular first premolar from the mesial view
less convex
where is the lingual height of contour of the mandibular first premolar from the mesial view
middle 1/3
where does the lingual height of contour lie in relation to the root from the mesial view of the mandibular first premolar
lingual to the outline of the root (hangs over the root)
where does the lingual cusp tip of the mandibular first premolar lie in relation to the root from the mesial view
lies on a line with the lingual border of the root
describe the difference in length from the CEJ to the lingual cusp tip compared to the length of the CEj to the buccal cusp tip
length from CEJ to lingual cusp tip is 2/3 distance from CEJ to buccal cusp tip
describe the mesial marginal ridge of the mandibular first premolar from the mesial view
sloped cervically from buccal to lingual
describe the mesiolingual developmental groove from the mesial view of the mandibular first premolar
separates lobe from the lingual lobe
describe the cervical line of the mandibular first premolar from the mesial view
curves occlusally about 1mm
describe the mesial surface of the mandibular first premolar
smoothly convex except for the mesiolingual developmental groove
describe the root of the mandibular first premolar from the mesial view
- tapered to a pointed apex
- deep developmental depression groove on the mesial surface
which marginal ridge is higher above the CEJ in the mandibular first premolar
the distal
which tooth is the only tooth with a mesial marginal ridge lower than the distal marginal ridge
mandibular first premolar
describe the distal marginal ridge of the mandibular first premolar from the distal view
distal marginal ridge is almost at right angles to the long axis of the tooth
- convex, may have concavity above the cervix extending buccolingually
describe the distal contact of the mandibular first premolar
contact is broader than the mesial
- height of contour is in the middle 1/3rd
describe the distal cervical curvature of the mandibular first premolar
less or similar to mesial curvature
describe the root of the mandibular first premolar from the distal view
- more convex than mesial - less grooved
- shallow developmental depression but no deep groove
what shape is the mandibular first premolar from the occlusal view
diamond
describe the buccal cusp and the lingual cusp of the mandibular first premolar from the occlusal view
-buccal cusp and ridge are pronounced
-lingual cusp is small
is the crown of the mandibular first premolar wider bucally or lingually
bucally
describe the MB and DB line angles of the mandibular first premolar from the occlusal view
prominent and quite rounded
where are mesial and distal contacts of the mandibular first premolar from the occlusal view
centered buccolingually
what is the transverse ridge of the mandibular first premolar from the occlusal view
the buccal and lingual triangular ridges joined together to form a single ridge
which ridge is larger on the mandibular first premolar: buccal or lingual triangualr ridge
buccal
is there a central groove on the occlusal surface of the mandibular first premolar
sometimes
what does the transverse ridge on the occlusal surface of the mandibular first premolar separate
mesial occlusal fossa from the distal occlusal fossa
which is larger on the mandibular first premolar: distal occlusal fossa or the mesial occlusal fossa
distal occlusal fossa
what does the mesiolingual developmental groove separate on the mandibular first premolar
the mesial marginal ridge from the lingual cusp
describe the root of the mandibular first premolar
-single
- rounded
-curves distally
-grooved on distal and mesial surfaces (mesial is larger)
- root may be bifurcated (rare)
what are the types of the mandibular 2nd premolars
-three cusp type (5 lobes)
- two cusp type (4 lobes)
what is the difference between the mandibular first premolars and the mandibular 2nd premolars from the buccal view
buccal cusp is shorter and less pointed
- mesial and distal contact areas are broad and appear higher on the crown due to smaller buccal cusp
where are the mesial and distal contacts of the mandibular 2nd premolars located
middle third, distal is more cervical
describe the root of the mandibular 2nd premolars from the buccal view
root is broader mesiodistally
- apex is more blunt
how does the mandibular 2nd premolars differ from the mandibular first premolar from the lingual view
-lingual lobes are better developed
- less of occlusal surface is visible
- root is wide mesiodistally but not as wide as buccal
if the mandibular 2nd premolars is the 3 cusp type what separates the 2 lingual cusps
the lingual groove
how does the mandibular 2nd premolars differ from the mandibular first premolar from the mesial view
- crown and root are wider buccolingually
- buccal cusp tip is not as lingually placed
- buccal cusp is shorter
- lingual and buccal cusps are more equal in size
where is the mesial marginal ridge of the mandibular 2nd premolars from the mesial view
at right angle to the long axis of the tooth
is there a mesiolingual developmental groove on the mandibular 2nd premolars
no
describe the root of the mandibular 2nd premolars from the mesial view
root is longer and apex is more blunt
how does the distal view of the mandibular 2nd premolars differ from the mesial view
distal marginal ridge is at a lower level and thus more of the occlusal surface is visible
what is the shape of the three cusp type mandibular 2nd premolars from the occlusal view
square
what are the cusps in the 3 cusp type of the mandibular 2nd premolars from the occlusal view and what is the order in size
2 lingual cusps and one buccal
buccal > mesiolingual > distolingual
describe the occlusal surface of the three cusp type of the mandibular 2nd premolars
- developmental grooves separate the cusps forming a Y shape on surface
-mesial, distal, and lingual developmental grooves - central pit
- mesial triangular fossa and distal triangular fossa
describe the occlusal surface of the two cusp type of the mandibular 2nd premolars
H or U shaped developmental grooves
- lingual convergence of the mesial and distal marginal ridges
- lingual cusp is well developed
- central developmental groove, mesial and distal fossae
- may or may not have mesial and distal pits
what is the shape of the mandibular 2nd premolars from the occlusal view
rounded
