Tooth morphology Flashcards
Difference between mesio-incisal and disto-incisal edge in incisors
mesio-incisal edge is sharper than the rounder disto-incisal edge
Which structures meet to form the cingulum?
Mesial and distal marginal ridges
How to differentiate between mesial and distal of incisors and canines using the cervical line
Mesial cervical line is more undulated than distal
Which teeth have a cingulum?
anterior teeth but less pronounced in lowers
Which tooth may have a fossa due to pronounced marginal ridges meeting on the palatal surface?
Upper lateral incisor (12,22)
Which is the most symmetrical anterior tooth?
Lower central incisors (41,31)
Feature of lower anteriors
lingually inclined
Which tooth has a fan shaped crown with a distal flare?
lower lateral incisor
Feature of incisal edge in youth
mammelons (3 cusplets)
Which tooth has the most prominent cingulum?
Upper canine (13,23) with 2 shallow fossae
Which teeth have a cuspid instead of an incisal edge?
canines
Which tooth has a palatal and labial ridge?
upper canine
How to distinguish between mesial and distal in canines?
cervical undulation. Mesial border is shorter and less steeply inclined than distal. Mesial contact point is more incisal than distal contact point.
Difference between mesial and distal contact points in upper canines
mesial contact point is more incisally located (lower) than distal contact point (higher) which is in the centre of the crown.
Which proximal side is smaller in canine?
Mesial side is smaller than distal
Longest and strongest tooth
upper canine
Difference in shape between upper and lower canines
upper canine is more spade-like, while lower canine is more slender
Difference between upper and lower canines
lower canines are lingually inclined and have a flatter labial surface (like lower incisors). Crown is at an angle to the root while in upper canines the crown is straight. Upper canines are more spade-like
Term used to describe canines leading jaw movement
canine guidance
On which sides are the 2 premolar roots?
Buccal and palatal
Which tooth has a canine fossa?
Upper first premolar (14,24) - concave mesial surface
In which tooth does the central groove usually extend over the mesial marginal ridge?
upper first premolar (14, 24)
in upper first premolars what is the difference in cusp size?
buccal cusp is bigger than palatal cusp
in upper second premolars what is the difference in cusp size?
buccal and palatal cusps are similar in size (buccal cusp reduced)
Which teeth have a mesial displacement of the palatal / lingual cusp?
Upper first premolars (14,24), upper second premolars (slightly - 14,25), lower second premolar if only one lingual cusp is present (45,35)
What percentage of upper second premolars have one root?
85% - deeply grooved distally
Which premolars have a more cervical distal marginal ridge than mesial?
Upper first (14,24), upper second (15,25), lower second (45, 35)
Which premolars have a more cervical mesial marginal ridge than distal?
Only lower first premolars (44, 34) - small groove runs from mesial pit to mesio-lingual surface
Difference in shape between upper and lower premolars
upper premolars are more oval while lower premolars are more round
Which tooth has a narrow, flat, bucally-pushed mesial contact point compared to a more rounded, wider distal contact point?
Lower first premolars (44,34)
Which tooth either has one lingual cusp or two lingual cusps?
Lower second premolar (45, 35) - either mesially-displaced large lingual cusp or a large mesio-lingual cusp and a small disto-lingual cusp
Which fossa is larger in lower second premolars? (45,35)
distal fossa larger than mesial fossa
How many roots do upper molars have?
3 roots - 2 buccal, 1 palatal
How many roots do lower molars have?
2 roots - mesial and distal
Where may a tubercle of Carabelli be found?
On the mesio-palatal cusp of upper first molar (16,26)
Which is the largest cusp in upper first molars?
mesio-palatal cusp is largest, disto-palatal cusp is smallest
Where is an oblique ridge found?
Extending from the mesio-palatal cusp to the disto-buccal cusp of upper first molar (16,26)
Shape of fissure in upper first molar (16,26)
H - distal fissure parallel to oblique ridge, mesial fissure has a right angled bend
Shape of upper first molars (16,26)
trapezoid
Shape of upper second molars (17,27)
more triangular
Which cusp is greatly reduced in upper second molars (17,27)?
Disto-palatal cusp
Which is the only tooth to have 5 cusps?
Lower first molar (46,36) - 3 buccal, 2 lingual
Shape of lower molars
more rectangular
In which teeth is the mesial root wider than the distal root?
Lower molars (47,46,36,37)
Which is the smallest cusp in lower first molars (46,36)?
distal cusp
Which tooth usually has a buccal pit/fossa?
Lower first molar (46,36)
Shape of fissure in lower second molar (47,37)
+ shaped. 4 cusps
Which tooth has a mesial hump?
Lower second molar (47,37) - mesio-buccal cusp is largest.
Difference in buccal and lingual surface of lower second molar (47,37)?
Buccal is convex, lingual is straight and higher
Difference in roots between upper first and second molars?
Both have 3 roots. Roots are less divergent in upper second molar (17,27)
How many roots do lower premolars have?
1
