Tooth morphology Flashcards
Primary vs Permanent
a) size
b) shape
c) colour
d) hardness
e) roots
f) pulp cavities
g) dentine thickness
a) smaller
b) more bulbous
c) whiter = more proteins, less minerals
d) enamel is thinner so softer
e) thinner, shorter and more diverged
f) larger
g) thinner
Why are primary teeth less susceptible to inter proximal caries?
Less crowded
Difference in pulp horn position between primary and permanent teeth?
Primary = closer to EDJ
What do all primary teeth possess on labial/palatal surface?
Low rounded labial cingulum
Crown shape of upper primary 1?
Transverses equal to vertical height
Mesial angle RA, distal angle rounded
Root of upper primary 1?
Conical root compressed in labio-palatal direction
Primary vs permanent upper lateral
Primary = more acute medial angle and more rounded distal angle
Root is compressed in labio-palatal direction
Primary vs permanent upper canine
Primary = symmetrical, if it isn’t the cusp is displaced distally unlike permanent
Much fatter
Primary molars
Crowns of first primary molar intermediate in shape between permanent premolars and molars
Primary 2nd molars resemble permanent 1st molars
Upper primary first molar
a) crown shape
b) buccal and palatal cusps
c) roots
a) irregular quadrilateral (4 cusps)
Buccal side wider and palatal side shorter
b) convergence of buccal and palatal cusps towards midline
c) 3 roots (2 buccal, 1 palatal)
Which incisors have mesiodistally compressed roots?
All lower incisors
What is the angle of the mesio-incisal edge of upper central incisors?
90
How can you distinguish between lower central and lower lateral incsiors?
Lateral = asymmetric fan shaped crown with distal angle more acute than medial
Incisal edge distally is curved lingually
Central = symmetrical rectangular crown = both angles 90
Which ridge is shorter on all canines?
Mesial
State 2 differences between upper and lower canines
Upper canine - larger and longer root
Lower = difference in length of ridges is less pronounced.
Has a labial cingulum and is inclined labially
Which ridge is steeper on all canines?
Distal
Which pre-molars have disto-lingual accessory cusps?
Lower 5 almost always and lower 4 often
Roots of upper 4?
One buccal one palatal root, sported by the canine fossa
Are upper or lower pre-molar crowns more circular?
Lower
Which tooth has canine groove and fossa?
Upper 4
Which tooth has canine groove?
Upper 4 and Lower 4
Difference in buccal cusps of lower 4 and 5
Lower 4 = very prominent buccal cusp and small lingual cusp
Lower 5 = better developed lingual cusp and smaller buccal cusp
On which tooth is the medial ridge straighter and longer than the distal?
Upper 4
Upper 4 vs Upper 5
Upper 4 usually has 2 roots (buccal and palatal) where as upper 5 has only one although it is deeply grooved
Buccal cusp of upper 5 is smaller than upper 4
Upper 4 has canine fossa and groove
