Difference between First and Second Premolar

Premolars are transition teeth that are present between the canine and molar teeth. In humans, there are a total of eight premolars present, two in each quadrant. They help in proper chewing and mastication of the food by transferring the food from canines to the molars. The premolars have atleast two cusps (the pointed, elevated feature on the teeth). There are no baby premolars.

The premolars are divided into mandibular and maxillary, and first and second premolars. Let us discuss them.

First Premolar

The first premolar is the one that is found just next to the canine on either side of the jaw. The two premolars, located in the upper jaw, are referred to as maxillary first premolar, and the two located in the lower jaw are called mandibular first premolar.

The function of the premolars is to ensure proper tearing of the food during mastication. The first premolars have two root canals. They have sharp and prominent cusps. The premolars are annotated with numbers, as per the universal system of notation. The right mandibular first premolar is 28, and the left is 21. The right maxillary first premolar is 5 and the left is 12.

Refer: Types of Teeth In Humans, Diagram and Functions

Second Premolar

The second premolar is the one that is found between the first premolar and the first molar on either. The two premolar located in the upper jaw is referred to as maxillary second premolar, and the two located on the lower jaw is called mandibular second premolar. The second premolars have one root, and their cusps are rounded and small.

The right mandibular second premolar is annotated as 29 and the left as 20. The right maxillary second premolar is 4 and the left is 13.

Refer: 10 Captivating Facts About Teeth

First vs Second Premolar

First Premolar	Second Premolar
Description
The premolar that is found away from the midline of the face, just next to the canine is referred to as the first premolar.	The second premolar is found away from the midline of the face, in between the first premolar and first molar.
Structure
It is sharper, with more prominent cusps.	It is rounded and the cusps are smaller.
Root
They have a smaller root.	They have a longer root anchoring the tooth into the gums.
Similar to
The first premolars are more similar to the canines.	The second premolars are more similar to the molars.
Number of Cusps
The mandibular first premolars have two cusps.	The mandibular second premolars have three cusps.
Activity of the Cusp
The lingual cusp (located near the tongue) in the mandibular first premolar does not take part in chewing.	All the three cusps in the mandibular second premolar are functional.
Universal Number of Notation
Mandibular first premolar: 28, 21 Maxillary first premolar: 5, 12	Mandibular second premolar: 29,20 Maxillary second premolar: 4, 13

Visit BYJU’S Biology for more.

Frequently Asked Questions on Difference between First and Second Premolar

How do you tell the difference between a first and second premolar?

The major visible difference between the first and second premolar can be observed in their cusps. The first premolar has more sharp and prominent cusps, but the second premolar has rounded and small cusps.

How do you differentiate maxillary first and second premolar?

The buccal cusp (near the cheek) is almost V-shaped and is more prominent than the second premolar.

What premolar often has three cusps?

The mandibular second premolar has three cusps.

Which premolar has two root canals?

The first premolars have two root canals.