Maxillary Premolars (objectives + highlights + quiz)

Premolars are also referred to as:

bicuspids

The general trend of the cervical line as you move posterior:

cervical line gets flatter

What is a distinguishing characteristic of the maxillary 1st premolar CUSP TIP from the buccal view?

This is the only tooth where the mesial cusp ridge is LONGER than the distal cusp ridge

From the buccal aspect, the maxillary 1st premolar cusp tip will lean slightly ____________.

distal

From the buccal aspect, the mesial outline of the maxillary 1st premolar crown between the medial contact area and the cervical line is slightly ___________.

concave

Buccal view: Why does the maxillary 1st premolar have a concaved mesial outline?

developmental root depression

(picture is from mesial view, not buccal)

Lingual view, maxillary 1st pre molar: The tip of the facial cusp is ____(a.)______ and the tip of the lingual cusp is ____(b.)______ to the mesiodistal long axis bisector.

a. distal (red dot)

b. mesial (blue dot)

Think: the 1st max premolar wants to be Like Mike = LM = lingual mesial

Mesial view, maxillary 1st pre molar: What is unique about the triangular ridges?

Slope towards the central groove is STEEPER than any other tooth

Think: The max 1st premolar is a "STaR" = steep triangular ridge. Also, triangles form the points of a STaR.

Mesial view, maxillary 1st pre molar: The mesial marginal developmental groove crosses the ridge and extends into the _____________________.

mesial developmental depression

occlusal view, maxillary 1st pre molar: What shape is the mesial contour? Why is it this shape?

shaped like a "3" due to the mesial marginal ridge groove

Think: Mesial --> m --> if you flip the "m" it looks like a 3

occlusal view, maxillary 1st pre molar: What shape is the distal contour?

convex

occlusal view, maxillary 1st pre molar: The mesial and distal fossae are connected by a ______________.

central groove (red line)

occlusal view, maxillary 1st pre molar: The central groove that extends over the mesial marginal ridge (MMR), onto the mesial surface is called ___________.

MMR Developmental Groove

(Picture: red circle)

Facial view, maxillary second premolar: Which facial cusp tip is shorter? Which is longer?

Mesial cusp = shorter (mesial = mini)

Distal cusp = longer

Which maxillary premolar facial cusp is more rounded?

2nd premolar

Note: mandibular premolars follow this same pattern

Typically, how many root(s) and pulp canal(s) will maxillary second premolars have?

one root

2 pulp canals

The proximal outline of all maxillary posterior teeth is described as a:

trapezoid

Mesial view, maxillary 2nd premolar: Which is more pointed, the facial cusp tip or the lingual cusp tip?

Facial cusp tip

Maxillary 2nd premolar: General rule of functional cusp in comparison to non-function cusps.

functional cusp is more rounded

Occlusal view: Which maxillary premolar will typically measure slightly smaller from the same dentition?

maxillary second premolars

Occlusal view: Which maxillary molar has a relatively short central groove and relatively wide marginal ridge?

2nd premolar

Occlusal view: How do the mesial and distal triangular fossae of the 2nd premolar compare to the 1st premolar?

on the 2nd premolar, the M&D triangular fossae are closer to the center of the tooth

From the occlusal aspect, why does tooth #4 have a "wrinkled" appearance?

Lots of supplemental grooves extending from the short central groove

Which tooth is the only permanent tooth where the mesial cuspal ridge of the facial cusp is longer than the distal cuspal ridge?

maxillary first premolar

Looking at #5 from the lingual, the lingual cusp appears _____ and the buccal cusp appears ______ to mesiodistal long axis bisector.

-mesial

-distal

On which tooth and surface would you find a marginal ridge developmental groove?

a. #12M

b. #4M

c. #5 D

d. #13D

a. #12M

Some distinguishing features of a maxillary second premolar that would help you identify it from a maxillary first premolar? (3 answers)

-Buccal cusp more blunt

-More supplemental grooves

-Mesial cusp ridge is shorter than the distal cusp ridge

A maxillary first premolar will most likely have ___ roots. A maxillary second premolar will most likely have ___ roots.

2,1

For all maxillary premolars, the facial height of contour is in the _____ third of the tooth. The lingual height of contour is in the ____ third of the tooth.

cervical, middle