[Biology Class Notes] on Premolar Teeth Pdf for Exam

Premolars or bicuspids or premolar teeth are a type of teeth present between our molars and our canine teeth. Humans have two sets of premolars for every quadrant leading to 8 premolars in total in our mouth. These premolars have at least 2 cusps and are used for chewing food.

They contain properties of both canines (in the front) and molars (in the rear), and they help food transfer from the canines to the molars. The function of premolar teeth is to act as a transitional vessel for the food from the front to the back of our mouth for proper breakdown, thus earning it the name of “transitional” teeth.

Structure of Premolars

The premolar teeth numbers are 8 in our mouth with 2 of each of the following –

• Maxillary first premolar

• Maxillary second premolar

• Mandibular first premolar

• Mandibular second premolar

The structure of these premolars all differ from each other. Let’s take a look at them.

1. Maxillary First Premolar

• The crown is more ovoid, being wider than the rest.

• At first, these first premolars look similar to their neighbor, the canines.

• They generally contain two roots but can sometimes have just one.

2. Maxillary Second Premolar

• Their shape and structure are similar to the first premolars but their distobuccal and mesial-buccal corners are more rounded.

• Their cups are more equal and smaller in size.

• They usually have one root.

• They have smaller occlusal fissures.

3. Mandibular First Premolar

• These premolars are the smallest out of the 4 premolars.

• They have a very short lingual cusp with a broader buccal cusp. The lingual cusp is just half the size of the buccal cusp.

• From the occlusal, only 2/3rd of the buccal surface of this premolar is visible.

• They usually have one root with a round or oval cross-section.

4. Mandibular Second Premolar

• Their crown is larger than even the mandibular first premolar.

• They have a smaller better-developed lingual cusp with a broader buccal cusp.

• The buccal and the lingual cusp is separated by an occlusal fissure which is both mesiodistal and well-defined.

• They usually have one root with a round or oval cross-section.

Taking Care of Premolar Teeth

The most common cause of premolar teeth pain is cavities. Due to their wide cusps, a lot of food gets stuck there leading to cavities. However, there is no extra special care to be taken of one’s premolars. Just like the rest of our teeth, premolars require thorough brushing twice daily with a good quality toothbrush. This will strengthen your tooth enamel. You can also use floss to clear out any plaque from your teeth.

Difference Between Premolar and Molar Teeth

There is very little difference between our molar and premolar teeth. But even that little difference is significant. Their main difference lies in their shape and size. Premolars might look wider and larger than your narrower canine teeth, but they are smaller than molars.

Again, while both molars and premolars contain fissures and pits in their cusps, the fissures are much deeper in the molars. This leads to a greater risk of cavities in your molars than in your premolars.

The molars and premolars also differ regarding the number of roots they have. Only the maxillary or the upper first premolar has two roots while the rest have a single root. On the other hand, the molars are always accompanied by roots except for the upper molars, which may also have three roots.

Premolars in Other Mammals

Premolars were found in primitive placental mammals. The premolar teeth numbers in them were 4 every quadrant but two of them, the medial ones (closest to the front of their mouth) have been lost already since apes and old world monkeys.

Fun Facts

• Human premolars are known as Pm3 and Pm4 by paleontologists.

• Our premolars are our most commonly removed teeth. Almost 48.8% of cases require the removal of premolars during orthodontic treatment.