Premolars Flashcards
Which premolar has a longer mesial cusp ridge than distal cusp ridge?
Max 1 premolar
Primary canines also have this feature
Which tooth has the most prominent transverse ridge
Mand 1 premolar
They also have a ML dev groove and a very small lingual cusp
Mand 2 premolar distal aspect
Tooth tilts distally, so the 3 cusps are visible from this view
Occlusal surface can be seen from distal view, which is a characteristic of all posterior teeth
Which is the only premolar with a central fossa
Mand 2 premolar
Lingual aspect of max 2 premolar
How many roots
What does it look like and which way does the root point
Lingual cusp is longer than the max 1 premolar
So max 2 premolar buccal and lingual cusps are more equal in size
Lingual cusp tip is offset to the mesial, ie mesial ridge is shorter than the distal ridge
Single root
Root points to the distal !!
Are mand or max premolars more alike?
Max premolars are more alike
Their buccal and lingual cusps are sim to the same height
Oblong faciolingually
Mand 1 premolar occlusal view
Shape, lobe
Diamond shape
Middle labial lobe makes up bulk of tooth, meaning a lot of the buccal surface can be seen from the occlusal
Very little of the lingual surface is seen because of the small lingual cusp
More bulk in distal half
Which premolar is the smallest
Mand 1 premolar
Max 1 premolar from mesial view
Mesial anatomy
Root and cusp lengths and #
Strength
Prominent mesial concavity (developmental groove) right below the contact area
This makes it harder to do interproximal fillings on the mesial bc the enamel is very thin in this area
And you may need to use a larger wedge
Two spindly roots
Makes tooth very weak and brittle
Buccal root and crown are longer than the lingual root and crown
Mesial marginal ridge groove present
Max 2 premolar occlusal aspect
Shape and ridge
Cusps and grooves
Symmetrical Less prom buccal ridge Buccal cusp offset to mesial Lingual cusp offset to mesial but not as much as max 1 Line angles are more rounded
Short central groove
No mesial marginal groove
More supplemental grooves
Mand premolar characteristics
Less alike than max premolars
Vary in shape
From the proximal view, the crowns are tilted lingually like all mand teeth
Buccal cusps are much larger than the lingual cusps
What groove pattern is visible on the mand 2 premolar 3 cusp type and 2 cusp type?
3 cusp type- Y shaped groove pattern
2 cusp type- U or H shaped groove pattern
Mand 2 premolar
Larger than mand 1
Longer root
Can have 2 or 3 cusps
Which is the only tooth with a mesial crown concavity
Max 1 premolar
Shape of max vs mand premolars
All premolars are longer buccolingually than mesiodistally, BUT
Max are more oblong shaped, MD is a lot shorter than BL
Mand are more square shaped, the difference in length is not as high
Which premolar appears to be “wrinkled” and oval shaped
Max 2 premolar
Canine guidance
When the canines function to protect the more fragile premolars (specifically max 1 premolars) from breaking and occluding too hard together
HOC of mand 1 premolar from proximal view
Middle third for both buccal and lingual
Mand 2 premolar mesial view
Not similar to mand 1 premolar
The marginal ridge is more horizontal and tooth appears to be tilted less lingually
There is no mesial dev groove on root
Triangular ridge
What do triangular ridges across from each other form?
From cusp tip to the central groove
2 across from each other form a transverse ridge
Which tooth is the only posterior tooth to have the mesial marginal ridge more cervical than the distal marginal ridge
Mand 1 premolar, it is also at a different angle than the distal ridge
Also has lingual groove, small lingual cusp, most prom transverse ridge
Mand 1 premolar resembles a ______ and the mand 2 premolar resembles a ____
Mand 1 - canine
Mand 2- molar
Which tooth has a mesial contact that is more cervical than the distal contact?
MAND 1 PREMOLAR!!!
Which mand premolar appears tilted more to the lingual
Max 1 premolar
Functions of specific premolars
First- assist canines is shearing and cutting food
All- support corners of mouth, keep from sagging
Function w molars to chew food
Maintain vertical dimension of face
Which premolar is likely to have two roots
Max 1 premolar
Max 2 premolar from the proximal view
Single root
No mesial concavity or groove
Cusps are more equal in size
Mand 2 premolar
2 cusp vs 3 cusp type
Describe each and Which is more common
3 cusp type is more common
Square shape
Buccal cusp > ML cusp > DL cusp
ML cusp is wider and longer than the DL cusp
Lingual groove separates them
2 cusp type
Round shape
Central groove is U or H shaped
Mand 2 premolar buccal view
Buccal cusp is shorter, and more rounded than mand 1 premolar
Mand 1 premolars have a buccal cusp that is _______ than mand 2 premolar
Sharper and taller
They resemble mand canines
Mand premolars from proximal view
Compare them
Crowns tip to lingual and they appear rhomboid shaped, more so on mand 1
Buccal cusps are longer than lingual cusps, more so on mand 1
Lingual aspect of max 1 premolar
What does it look like and which way to roots point
The crown and root is narrower, so you can see the buccal crown and root from this view
Roots point towards the mesial!!!
Lingual root is shorter than the mesial
Lingual lobe of premolars forms what? In anterior?
Lingual lobe of premolars forms lingual cusp
In anteriors it forms the cingulum
Mand 1 premolar
Buccal and lingual view
Cusp tip more towards mesial, mesial ridge shorter than distal ridge
MESIAL CONTACT IS MORE CERVICAL THAN DISTAL CONTACT
Very small lingual cusp, entire occlusal surface visible from lingual
ML developmental groove
Prominent transverse ridge
Where does the bifurcation begin on max 1 premolar
In the apical third
Which cusp type is most common in mand 2 premolars
The 3 cusp type
Max 1 premolar resembles which tooth
The canine
Except the cusp tip of the premolar is placed more distally
Cusp tip of max second premolar cusp tip is more ______ and _____ than max 1 premolar
More mesial and more rounded
How many developmental lobes make up the facial/lingual face of premolars
Facial is 3 lobes
Lingual is 1 lobe
Compare shapes of mand premolars
Mand 1 is diamond shape bc of large middle labial lobe
Appears to be more bulky towards the distal bc of buccal cusp position, and bc of the ML groove
The ML area is flattened
Mand 2 is often more square
Can have 2 or 3 cusps
Max 1 premolar occlusal view
Shape and ridge
Grooves and cusps
Asymmetrical
Buccal ridge is more prominent
Buccal cusp offset to distal
Lingual cusp offset to mesial
Long central dev groove runs across entire transverse ridge
The mesial marginal ridge groove makes the central groove look even longer
Few supp grooves
Mand 1 premolar from the mesial view
Cusp locations and groove and root
Tip of buccal cusp is centered over root
Tip of lingual cusp is centered over the lingual border of root
This makes the tooth appear to have a steep angle, sloped downwards to the lingual
Can see the ML groove
Short root with deep developmental groove
Which tooth is most likely to be removed to make room on the mand arch
Mand 1 premolar
Sometimes the mand 2 premolar is removed, depends on how much space is actually needed
