Dental Anatomy: Maxillary First Premolars

Questions and Answers

What is the number of maxillary first premolars in an individual?

Two

What is the relationship between the lengths of the buccal and lingual cusps of the maxillary first premolar?

The buccal cusp is usually about 1 mm longer than the lingual cusp

How many roots are present in most maxillary first premolars?

Two roots

What is the function of the maxillary first premolars?

Tearing Signup and view all the answers

At what age do the maxillary first premolars erupt?

10-11 years Signup and view all the answers

What is the shape of the crown of the maxillary first premolar from the buccal aspect?

Roughly trapezoidal Signup and view all the answers

What is the characteristic of the mesial outline of the crown from the cervical line to the mesial contact area?

It is concave Signup and view all the answers

What is the position of the crest of the curvature of the contact area when the tooth is posed with its long axis vertical?

It is immediately occlusal to the halfway point from the cervical line to the tip of the buccal cusp Signup and view all the answers

What is the shape of the mesial aspect of the crown of the maxillary first premolar?

Trapezoidal Signup and view all the answers

Where is the crest of curvature located on the buccal outline of the crown?

At the junction of cervical and middle thirds Signup and view all the answers

What is the characteristic of the cervical line curvature on the mesial aspect of the maxillary first premolar?

It is less convex than the cervical curvature on the mesial side of any of the anterior teeth Signup and view all the answers

Where is the tip of the lingual cusp located in relation to the lingual border of the lingual root?

On a line with the lingual border of the lingual root Signup and view all the answers

What is the characteristic of the buccal outline of the crown from the crest of curvature?

It continues as a line of less convexity Signup and view all the answers

What is the name of the marked depression on the mesial surface of the crown?

Canine fossa Signup and view all the answers

What is the shape of the lingual outline of the crown?

Smoothly curved Signup and view all the answers

Where is the crest of curvature of the lingual outline of the crown located?

Near the center of the middle third Signup and view all the answers

What is the shape of the buccal surface of the crown?

Convex Signup and view all the answers

What is the name of the continuous ridge from cusp tip to cervical margin on the buccal surface of the crown?

Buccal ridge Signup and view all the answers

How do the mesial and distal slopes of the lingual cusp meet?

At an angle of about 90 degrees Signup and view all the answers

What is the shape of the lingual cusp from the cervical portion to the area near the cusp tip?

Spheroidal Signup and view all the answers

Which of the following is true about the lingual root apex?

It is more blunt than the buccal root apex Signup and view all the answers

What can be seen from the lingual aspect of the crown?

Part of the mesial and distal surfaces of the crown and root Signup and view all the answers

How do the mesial and distal outlines of the lingual portion of the crown relate to the mesial and distal slopes of the lingual cusp?

They are continuous with the mesial and distal slopes of the lingual cusp Signup and view all the answers

What is the relative length of the mesial slope compared to the distal slope?

The mesial slope is longer than the distal slope Signup and view all the answers

What is the characteristic of the mesial concavity of the maxillary first premolar?

It continues apically beyond the cervical line and joins a deep developmental depression between the roots Signup and view all the answers

What is the function of the mesial marginal developmental groove?

It has no specific function Signup and view all the answers

What is the difference between the distal and mesial contacts of the maxillary first premolar?

The distal contact is more occlusally and more extended Signup and view all the answers

What is the characteristic of the root trunk of the maxillary first premolar?

It is long and bifurcated for half its total length Signup and view all the answers

What is the difference between the cervical line curvature on the mesial and distal aspects of the maxillary first premolar?

The cervical line curvature is less pronounced on the distal aspect Signup and view all the answers

What is the characteristic of the developmental groove on the distal aspect of the maxillary first premolar?

It is shallow and insignificant Signup and view all the answers

What is the characteristic of the bifurcation of the roots of the maxillary first premolar on the distal aspect?

It is abrupt and has no developmental groove leading to it Signup and view all the answers

What is the characteristic of the root trunk on the distal aspect of the maxillary first premolar?

It is longer than on the mesial aspect Signup and view all the answers

Study Notes

The Permanent Maxillary First Premolars

Located in the right and left maxilla, posterior to the canines and immediately anterior to the premolars
Also known as bicuspids, with the buccal cusp being about 1 mm longer than the lingual cusp
Most maxillary first premolars have two roots (about 80%) and two pulp canals, even when only one root is present
Function like canines, with a tearing action
Erupt between 10-11 years of age, with root completion occurring between 12-13 years

Buccal Aspect

Crown is roughly trapezoidal in shape
Cusp tip tilts distally
Mesial outline of the crown is slightly concave from the cervical line to the mesial contact area
Distal outline of the crown is straighter than the mesial, and may be somewhat concave
Buccal surface of the crown is convex, with strong development of the middle buccal lobe
Two shallow developmental grooves and two mesial and distal lobes are present

Lingual Aspect

Mesial and distal outlines of the lingual portion of the crown are convex
Cervical line is regular, with slight curvature towards the root and the crest of curvature centered on the root
Lingual cusp is smooth and spheroidal, with a pointed cusp tip
Apex of the lingual root of a two-root specimen tends to be more blunt than the buccal root apex

Mesial Aspect

Crown is roughly trapezoidal in shape
Cervical line curvature is less than on the mesial side of anterior teeth
Buccal outline of the crown curves outward below the cervical line
Lingual outline of the crown is a smoothly curved line
Mesial developmental depression (canine fossa) is present on the mesial surface of the crown
Mesial marginal developmental groove is present on the mesial surface of the crown

Distal Aspect

Distal contact is more occlusally and more extended than the mesial contact
Curvature of the cervical line is less on the distal than on the mesial surface
No deep developmental groove crosses the distal marginal ridge of the crown
Bifurcation of the roots is abrupt, with no developmental groove leading to it
Root trunk is longer on the distal side, making the bifurcation more apically

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Description

This quiz covers the basics of maxillary first premolars, including their location, number, and relation to other teeth. It is designed for dental students.