Thư viện chuyên khoa

What Are Molars? Is There Any Replacement?

What Are Molars? Is There Any Replacement? When it comes to molars, we are often warned that they are extremely important teeth. However, not everyone understands exactly what molars are. So what number is the molar tooth? Do baby molars replace? Can lost molars grow back? The article below will help you learn about what premolars and molars are.

What are some concepts about molars? What are molars?

What are molars? What is a molar is always a concept that many people are interested in. Because many people know that they are very important but do not define exactly which teeth are molars.

What are molars?
What are molars? What are premolars? Do molars grow back?

So what are molars? Molars are also known as molars. These are the teeth that grow on the inside of the jaw. It protects the jawbone and is responsible for chewing.

Molars are located within two incisors and one canine tooth. Each quadrant of the jaw will have two premolars and four large molars.

What are premolars?

Premolars is a concept that refers to molars. Specifically, this term refers to premolars. Or you may know premolars as premolars and premolars.

Learn about molars

3D Medical Animation Still Showing Types of Teeth
What are molars? What are premolars? Do molars grow back?


When learning about molars, you need to understand the number of molars. An adult usually has 12 molars. 6 on top and 6 on bottom. Each side of the upper and lower jaw will have 3 molars.

They occupy the posterior part of each hemiarch. In addition, this is a group of teeth that do not grow to replace baby teeth, they are called successor teeth.


Time of molar eruption

First molars usually erupt when we are about 6 years old. This is the first permanent tooth to grow in the oral cavity. The second molars will erupt when we are about 12 years old. The third molars are often called wisdom teeth and they grow at different times depending on each person’s constitution.


Large molars are responsible for chewing and crushing food. At the same time, it also maintains the vertical dimension of the floor below the surface. The position of the teeth relative to the temporomandibular joint will help the teeth have the best grinding function.

Shape of molars

The most recognizable characteristics of molars are:

  • They are called molars because they have the largest chewing surface on the dental arch.
  • Each molar usually has 3 – 5 large cusps.
  • This is the only group of teeth where each tooth has at least 2 outer cusps.
  • There are two or three large roots, and the position and direction of the roots are most characteristic of the group.
  • The chewing surfaces of molars are quite cusped with solid roots.
  • About the upper molars

Characteristics of the upper molar group are as follows:

Size of molars mm Molar number 6 Molar number 7 Molar number 8
High crown of teeth 7.5 7 6.5
Near and far from the tooth crown 10 9 8.5
Outside inside the tooth crown 11 11 10
Total high 18 17.5 19.5
Age of growth 6 12 18+
  • They usually have 3 legs: two outer and one inner.
  • Usually there are 3 large segments and one smaller segment.
  • The molar crown has a buccolingual dimension larger than the mesiodistal dimension.
  • The mesial lingual cusp of the molar and the distal buccal cusp have triangular ridges that join together to form diagonal ridges.
  • The mesiobuccal, mesiobuccal and mesilingual smells of the molars will form a triangular pattern with 3 cusps.
  • The two outer zones are not equal in size. Usually the mesial buccal zone is larger than the distal buccal zone.
  • The lingual cusp of the molar is usually small or very small. There are even cases where there is none.

Below is a table of size and age of upper molars:

Size of molars mm Molar number 6 Molar number 7 Molar number 8
High crown of teeth 7.5 7 6.5
Near and far from the tooth crown 10 9 8.5
Outside inside the tooth crown 11 11 10
Total high


17.5 19.5
Age of growth 6 12 18+

About the lower molars

The lower molars occupy the posterior portion of each side. Similar to the upper molars, their size will also gradually decrease. Below are some unique characteristics of mandibular molars:

  • Mandibular molars usually have two roots, one mesial and one distal.
  • Lower molars usually have 4 large cusps and a smaller 5th cusp.
  • The tooth crown has a greater mesiodistal dimension than the buccal-lingual dimension.
  • Lower molars are teeth with two large cusps on the inside of equal size.
  • Their mesial and distal cusps are also similar in size.
  • The upper and lower first molars are both permanent teeth that erupt at the age of 6. They are just distal to the second molar. They also mark the beginning of the mixed dentition milestone. That means with the simultaneous presence of both baby teeth and permanent teeth on the dental arch.
225349 anatomy ot the tooth 1296x1296 body.20200716143350801
What are molars? What are premolars? Do molars grow back?


Below is a table of size and age of eruption of lower molars:

Size of molars mm Molar number 6 Molar number 7 Molar number 8
High crown of teeth 7.5 7 7
Near and far from the tooth crown 11 10 10
Outside inside the tooth crown 10.5 10.5 9.5
Total high 21.5 20 18
Age of growth 6 12 18+

Learn about premolars

In English, premolars are called by another name Bicuspid – two-cushion teeth. However, not all premolars have two cusps, so this name is not widely used.

Time of eruption of premolars

Each of us will have a total of 8 premolars on the dental arch. Premolar teeth will grow to replace baby molars. They will grow between 9 and 11 years old, before the 2nd molars erupt.

The upper and lower first premolars erupt relatively evenly, usually by age 9. Next are the second premolars that erupt around age 11.


In primitive humans there would be 4 premolars in each quadrant, or 16 per person. Over time, the central premolars were lost. Paleontologists call these intermediate premolars 3rd premolars and 4th premolars.

Shape and function

Premolars grow in the position between canines and molars on the dental arch. In terms of morphology, they are considered a transition between canines and molars. And as we know, canine teeth have a wedge-shaped cusp, responsible for the function of biting or tearing.

While molars have many cusps and a wide chewing surface. They will take on the function of chewing and grinding,

Premolars have at least one large, sharp cusp relative to the buccal cusp of the lower premolar. Or have 2-3 cusps and a small chewing surface compared to molars, suitable for the function of crushing food.

About the upper premolars

Outstanding features of the upper premolars are:

  • The upper 1st and 2nd premolars are more similar to each other than the lower teeth.
  • The upper premolars will have two large, raised cusps of equal size. This is completely different from the lower molars.
  • If viewed from the chewing side, the premolars will have a buccolingual dimension larger than the mesiodistal dimension.
  • Viewed from the side, the maxillary premolars will have an outer border that is only slightly inclined lingually, from the point of maximum buccal convexity to the tip of the buccal cusp.
  • Viewed from above, the premolars will have their maximum lingual prominence in the middle third.

Below is a table of sizes and growth ages of the upper premolars:

Size mm Premolar 1 Premolar 2
High crown of teeth 9.3 8.8
Near and far from the tooth crown 7.5 9.5
Outside inside the tooth crown 9.7 9.5
Total high 22.5 22.2
Near and far from the Premolar 5.3 5.3
Outside inside the Premolar 8.7 8.8
Age of growth 9 10

About the lower molars

Mandibular premolar number 1 is likened to a canine tooth. The second lower molar is like a miniature molar.

The characteristics of premolars are:

  • The size of the outer zone is much larger than the inner zone.
  • The tooth crown has a buccal and lingual dimension approximately equal to the mesio-distal dimension.
  • Seen from the side, the outer contour is much more inclined than the inner.
  • The maximum prominence is in the occlusal third.
  • The middle groove often curves inwards.

Here is a table of the size and age of teeth eruption for the lower premolars:

Size  mm Premolar 1 Premolar 2
High crown of teeth 9.5 9.0
Near and far from the tooth crown 7.8 7.8
Outside inside the tooth crown 8.5 9.0
Total high 24 24
Near and far from the Premolar 5.0 5.2
Outside inside the Premolar 7.3 7.7
Age of growth 9 10

What is the difference between upper and lower premolars?

Some common characteristics help distinguish upper and lower premolars:

  • The upper first and second premolars are more similar to each other than the lower molars. However, the crown of the upper first premolar is usually larger than the second tooth. Additionally, in the lower jaw, the first premolars will be smaller than other teeth of the same type.
  • From the mesial and distal sides, the lower molar crowns are often lingually inclined relative to the roots. While the upper teeth are more aligned.
  • The upper premolars have two occlusal cusps of nearly equal size. Lower premolars may have more than two cusps. The cusps inside the lower teeth are usually few and not as obvious as the outer cusps.
  • The buccal cusp being longer than the lingual cusp is the most prominent difference between the mandibular first premolars and the least prominent with the maxillary second premolars.
  • The upper first premolars usually have two roots. While other premolars only have one root.
  • Answering questions about molars

Are molars replaced?

After knowing what molars are, many users still wonder if molars can be replaced. In fact, in children from 7 to 12 years old, there will be a process of permanent teeth growing to replace baby teeth.

The order of tooth replacement for the upper molars is the central incisors, then the lateral incisors. Next, the premolars, canines and molars will be replaced last.

However, for the lower jaw, the canines will be replaced before the premolars. The remaining teeth will also be replaced in the same order as the upper molars.

Note that there will be cases where children’s molars will be replaced and not replaced, specifically:

See more: How much does tooth scaling cost at BeDental? 4 benefits of scaling teeth

Molars do change

These are the molars in the milk teeth. When it comes to age, it will loosen and fall out, leaving space for permanent teeth to grow. Most of the time, molars number 1, 2 on the upper and lower jaw will be molars with replacement. Age range is 10 – 12 years old.

Dental bonding 6
What are molars? What are premolars? Do molars grow back?

Molars do not change

The molar that is not replaced is usually molar number 3. This is a permanent tooth and does not go through the process of replacing baby teeth. Therefore, you need to help your baby take care of and preserve these teeth carefully.

Do molars grow back?

Do molars grow back? When molars have grown into permanent teeth, you need to take care of them carefully because once lost, they will not grow back. However, you don’t need to worry too much because if you lose teeth due to any reason, you can still get dentures.

Currently, there are many aesthetic restoration techniques for missing molars, ensuring both chewing function and aesthetics.

Instructions to protect molars from disease

When lost, molars will seriously affect chewing ability and aesthetics. Therefore, it is necessary to protect and prevent the risk of molar disease such as tooth decay, periodontitis, etc. on molars.

  • To do this, you need to pay attention to some cleaning methods as follows:
  • Maintain proper oral hygiene and brush your teeth at least twice a day.
  • Use dental floss or a waterpik to clean between your teeth perfectly.
  • Scientific and reasonable nutrition. It is especially necessary to provide adequate calcium. Limit foods containing sugar because it affects tooth enamel and gums.
  • Limit bad habits such as teeth grinding, smoking, alcohol, etc.
  • You should have regular dental check-ups and scaling.
scaling root planing
What are molars? What are premolars? Do molars grow back?

Hopefully the above article has helped you understand all the information about molars. If you have any other questions, please contact BeDental for advice and support. The team of good dentists here will help you with a general examination.

See more: Cavities Between 2 Molars (Interdental Caries) and Effective Treatment Methods



Address 1: 7B Thi Sach St, Ngo Thi Nham, Hai Ba Trung Dist, Ha Noi. - 0934.61.9090
Address 2: 343 Tay Son St, Nga Tu So Ward, Dong Da Dist, Ha Noi. (Nga Tu So Cross) - 0934.61.9090
Address 3: CC2 Tower  Nguyen Huu Tho St, Dinh Cong Ward, Hoang Mai Dist, Ha Noi. (Inside True Hope ) - 0934.61.9090
Address 1: 53 -55 -57  Pho Duc Chinh St, Nguyen Thai Binh, Dist. 1, Ho Chi Minh. - 0766.00.8080
Address2: 25, City Land urban area, Go Vap Dist, Ho Chi Minh - 0766.00.8080
Working: 9am - 6pm everyday

Rate this post