Permanent Posterior Teeth Flashcards
one or more major elevations on the masticatory
surface of canines and posterior teeth
Cusp
linear elevation on the masticatory surface of
posterior teeth
Ridge
sloping planes located between cusp
ridges on posterior teeth
Inclined cuspal planes
similar to fissure but not as deep a cleft
Groove
small pointed depression in enamel, usually at the
junction of two or more developmental grooves
Pit
deep cleft; developmental line usually found on the
occlusal or buccal surface, usually from the imperfect fusion
of dental lobes
Fissure
primary groove that marks the
junction among the lobes on
the lingual of anterior and
occlusal in posterior
Developmental Groove
the most prominent developmental groove on posterior teeth which usually travels mesiodistally
Central Groove
secondary groove that is
shallower, more irregular and
moves out from developmental
groove
Supplemental Groove
ridge that descends from each
cusp tip on posterior teeth
Cusp Ridge
rounded raised borders on
on the mesial and distal portion of the
lingual surface of anterior and the
occlusal table of posterior teeth
Marginal Ridge
cusp ridges that descend
from the cusp tip toward the central
portion of the occlusal table
Triangular Ridge
ridge formed by the joining of two triangular ridges crossing the occlusal table from labial to lingual; should be roughly parallel to the marginal ridges
Transverse ridge
ridge that crosses the occlusal
table of maxillary 1st and 2nd molars
only; at a diagonal angle to distal
marginal ridge
Oblique ridge
• Wide occlusal surface for chewing and grinding
• Central grooves are prominent grooves that traverse
mesiodistally
• Supplemental grooves, pits, fossa and ridges appear in varying
degree on the surface
• Occlusal appears wrinkled, increases the more posterior you
go
• Buccal and lingual view, crown appears trapezoidal (four sided)
• Contact area is much wider than anterior teeth
• Roots of molars are closer together as you go posterior.
• The more posterior a tooth, the more variation in anatomy. • CEJ is quite straight unlike the anterior teeth.
• More occlusal surface is visible from distal aspect!!!!!!
• Usually distal and lingual convergence.
General Characteristics of posterior dentition
For posterior teeth is more occlusal surface visible from the distal or mesial aspect
DISTAL
Usually posterior dentition will have mesial or distal lingual convergence
distal
Which of the following features is found only
on Maxillary 1st and 2nd molars?
Oblique ridge
• Older term is bicuspid
• Two or more cusps with one on buccal and one or two on
lingual (develop from 4-5 lobes, 3 facial and 1-2 lingual)
• Premolars are succedaneous • Shorter crown than anterior teeth
• Height of contour (crest of curvature) on buccal surface is in
the cervical 1/3, and lingually is the middle 1/3
• Usually have one root (except for maxillary first premolar) with
root concavities
General Characteristics for Premolars
• Maxillary premolars demonstrate mesial
inclination on lingual cusp
• Wider buccolingually than mesiodistally
General characteristics of Max. Premolars
Do maxillary premolars demonstrate inclination on a cusp
yes. mesial inclination on the lingual cusp
You are examining an extracted molar. It has
two roots, and 5 cusps. The roots are widely
spread, with the mesial root demonstrating a
deep concavity along the mesial surface.
Which molar are you examining?
Mandibular 1st
You are examining an extracted premolar. The
premolar in question is almost square in shape
when viewed from the occlusal plane, has two
cusps, and one root. There is no mesial root
groove and no mesiolingual groove on the
crown. The lingual cusp shows no mesial
inclination. Both cusps are in the occlusal
plane. Which premolar are you looking at?
Mandibular second premolar
Maxillary First Premolar
• From proximal view, two major cusps, one buccal and one lingual, both centered over root trunk • Buccal cusp about 1mm longer than lingual cusp (from lingual or proximal view, lingual cusp is smaller) • Mesial inclination on lingual cusp • Mesial marginal groove (not 100%), if it has a distal marginal groove, the mesial is still deeper • Mesial root groove (proximal root concavity)—depression actually begins just below the contact. What does this mean for us? • Only tooth in the permanent dentition with the mesiobuccal cusp slope that is longer than the distal • Usually has a bifurcated root at the apical third (one lingual, one buccal) • From distal proximal view, more occlusal surface is visible because distal marginal ridge is more cervically located
Only tooth in the permanent dentition with the mesiobuccal cusp slope that is longer than the distal
Maxillary first premolar
Does the maxillary first premolar always have a bifuracated root
no single root occurs 20 %
Does the maxillary first premolar have 2 pulp canals if it has one root
Yes always
which premolar has a mesial depression on root surface
maxillary first premolar
which maxillary premolar has even lingual and buccal cusps
maxillary second premolar
which premolar has a central groove does not cross the marginal ridge and has a wrinkled appearance
maxillary second premolar
• No depression on mesial or distal crown surfaces • Unlike the first premolar, the lingual cusp is closer to the same size as the buccal cusp • Central groove is shorter than first premolar with frequent supplemental grooves, but none that cross the marginal ridge, more wrinkled appearance • Lingual cusp offset to mesial • Occlusal view is more rounded/oval than first premolar
Max. Second Premolar