Permanent Molars Flashcards
what is the shape of the occlusal surface of an upper first molar?
diamond-shaped
what is the largest cusp on the upper first molar
the mesio-palatal cusp
what is the smallest cusp on the upper first molar?
the disto-palatal cusp
what is the longest diagonal on the occlusal surface of the upper first molar?
it goes from the mesio-buccal to the disto-palatal cusp
what is an oblique ridge
a strong ridge of enamel on the occlusal surface of a tooth
what is present on each side of the oblique ridge on the upper first molar
a fissure
what are the two fissures on the upper first molar connected by and what does this look like
they are connected with another shallow fissure which gives rise to an H-shaped fissure pattern
where does the distal fissure on the upper first molar run?
parallel to the oblique ridge and continues to the palatal surface
what does the mesial fissure on the upper first molar look like?
it has a right-angled bend and one arm runs towards the mesial surface (but not on to it) while the other goes to the buccal surface
what is a tubercle of carabelli and where is it found?
it is an extra cusp and it is found on the palatal surface of the mesio-palatal cusp on the upper first molar
how many roots does an upper first molar have and where are they?
3 roots - 2 buccal and 1 palatal diverging from a common root stalk
what is significant about the disto-palatal cusp on the upper second molar?
it is greatly reduced and may be absent altogether which makes the shape of the crown more triangular
what is the shape of the upper second molar crown?
triangular/heart-shaped
what can be said about the roots of the upper second molars
they are much less divergent and the palatal root is often partially fused with either of the buccal roots
what is the crown of the upper third molar like and how many cusps does it have?
smallest of them all and usually only 3 cusps (no disto-palatal)
what are the roots of the upper third molar like?
usually fused together into one common bulky root with grooves where the usual furcations would be
what is the smallest cusp on the lower first molar?
the distal cusp
how many cusps does the lower first molar have?
5 - 3 buccal and 2 lingual
where does the transverse fissure on the lower first molar run?
from the buccal surface to the lingual surface
what causes the formation of a pit in the centre of the lower first molar crown?
the deepening of the transverse fissure
what does the mesio-distal fissure do when it reaches the distal cusp
it bifurcates to pass onto each side of the distal cusp
is the buccal or lingual surface of the lower first molar larger?
the buccal surface
what shape are the proximal surfaces of the lower first molar?
convex with the distal much rounder because of the distal cusp
how many roots does the lower first molar have?
2 - one mesial and one distal both compressed mesio-distally and may show distal curvature
