Teeth ( The Gems ) Function & Disorders

Teeth ( The Gems ) function and disorders

Table of Contents

Teeth are one of the important and sensitive parts of our body that play a big role in chewing food, talking, laughing and the beauty of our face. Teeth are not only important for digesting food, but also play a significant role in communication and aesthetics. 

A healthy and attractive smile can boost self-confidence and improve social interactions. In addition, the teeth provide structural support and prevent sagging of the face and sunken cheeks.

Dental anatomy is a science that studies the structure, shape, size, composition, reproduction and function of teeth and related tissues. 

This science examines the evolution, difference, similarity and role of human and animal teeth.

Dental anatomy is an old science that has its roots in ancient times. Some of the earliest evidence of dental anatomy has been found in Egyptian, Babylonian, Indian, and Chinese cultures. 

These cultures cared about the shape, number, role and treatment of their teeth and their animals.

Entering the historical period, dental anatomy was recognized as an independent science and some famous doctors and philosophers such as Hippocrates, Aristotle, Galen and Ibn Sina investigated and explained it. 

These people helped to identify the structure, number, role and diseases of the teeth and suggested treatment methods such as filling, extraction, cleaning and oral massage.

With the beginning of the modern era, dental anatomy changed with scientific and technological advances and new and better methods were invented to study, teach and treat teeth. Some of these methods include: the use of a microscope, radiography, 3D imaging, DNA analysis, stem cells, dental prostheses, dental implants, and lasers. 

These methods have helped to identify the differences, similarities and evolution of human and animal teeth and have led to the improvement of oral health and beauty.

Types of teeth

There are four types of teeth: incisors, canines, premolars, and molars. Each type of tooth is for specific functions and has distinctive characteristics.

  • Incisors

    Incisors are the front teeth that are located in the upper and lower jaw and are used for biting and cutting food. They have sharp edges that make them ideal for biting into food. Incisors are the second group of human teeth that are next to canines. 

This group of teeth in dental anatomy is smooth and rectangular and is used for biting and crushing food. The incisors are medium and wide and there are four in each jaw. In total, humans have eight incisors: four in the upper jaw and four in the lower jaw.

  • Canine teeth

    Canines are sharp pointed teeth that are located next to the incisors and are used to tear and grab food. They have a long, pointed shape that allows them to penetrate and tear through food. Canine teeth are the first group of human teeth that are located in the front of the mouth. 

Canines are sharp and triangular and are used to cut and tear food. Canines are small and narrow and there are two in each jaw. In total, humans have four canines: two in the upper jaw and two in the lower jaw.

  • Posterior teeth

    Posterior teeth are the third group of human teeth that are located behind the incisors. This group of teeth in dental anatomy are rough and pitted and are used to crush food. 

The posterior teeth are large and thick and there are six in each jaw. In total, humans have twelve posterior teeth: six in the upper jaw and six in the lower jaw:

    • Premolar teeth

      Premolars are located between canines and molars and are used for grinding and crushing food. 

They have a smooth surface as well as indentations that make them ideal for grinding and chopping food.

    • Molar teeth

      Molars are back teeth that are located in the upper and lower jaw and are used for grinding and chewing food. They have a large surface area and multiple roughnesses that make them ideal for grinding and chopping food.

    • Wisdom tooth

      Wisdom teeth are the third molars located at the back of the mouth. They usually develop in the late teens or early twenties and are often pulled due to excessive irregularity and potential teething problems. 

Wisdom teeth are the fourth and last group of human teeth located at the end of the jaw. These teeth in the anatomy of the teeth, like the back teeth, are rough and pitted and are used to crush food. 

Wisdom teeth are big and thick and there are two in each jaw. In total, humans have four wisdom teeth: two in the upper jaw and two in the lower jaw.

Of course, it should be noted that wisdom teeth may not grow in some people or may come out irregularly or incompletely. 

This issue may occur in dental anatomy due to lack of space, genetic defects, damage to dental floss, or contact with neighboring teeth.

  • Baby teeth

    Milk teeth are the first set of teeth that grow in a child’s mouth. They are essential for chewing and speaking and provide space for permanent teeth to grow. So you should try to Keep your Children’s Baby Teeth.

  • Permanent teeth

    Permanent teeth are the second set of teeth that replace milk teeth. They are essential for chewing, talking, and maintaining beauty, and with proper care, they last a lifetime.


The difference between deciduous and permanent teeth

Milk and permanent teeth are different in terms of the number of teeth, growth time, shape and size. Baby teeth are smaller and fewer in number than permanent teeth and usually erupt between six months and three years of age. And it is important to know that How to Save Your Child’s Baby Teeth?

On the other hand, permanent teeth begin to grow at around six years of age and continue to grow until early adulthood.

How do different types of teeth help digestion?

Different types of teeth help digestion by breaking down food into small particles. The incisors and canines are responsible for biting and cutting food, while the premolars and molars grind and crush food, making it easier for the body to absorb nutrients. 

Without proper chewing, the body may have trouble breaking down food, leading to digestive problems.

  • The importance of chewing correctly

Proper chewing is essential to maintain digestion and oral health. Chewing food thoroughly helps break down food into smaller particles, making it easier to digest and absorb nutrients. In addition, proper chewing can help prevent dental problems such as cavities and gum disease.

  • How teeth work together

The teeth work together to break down food into small particles, making it easier for the body to absorb nutrients. Molars and canines are responsible for biting and cutting food, while premolars and molars grind and crush food.

Digestion begins in the mouth, where the teeth break down food into small particles. Then the food goes through the esophagus to the stomach, where it is further broken down by stomach acid and enzymes.


Structure and components of teeth

Dental anatomy in dentistry is a branch of dental science that studies the structure and components of teeth in detail. 

Each tooth consists of three main parts: crown, neck, and root. Each part is made of several layers and textures, each of which has its characteristics and functions.

Crown: the upper part of the gum in the anatomy of the tooth

Part of the dental anatomy includes the crown, which is the visible part of the tooth and is located above the gum. The crown consists of three layers: enamel, dentin, and pulp.

  • Enamel

Tooth enamel is the outer surface of the tooth crown. Enamel is a hard mineral tissue composed of hydroxyapatite crystals. 

Enamel is white, transparent and the hardest tissue in the body. Enamel has a protective role and protects dentin and pulp against pressure, heat, cold, and bacteria. Enamel also helps transmit light to the tooth and enhances its beauty.

  • Dentin

Ivory is the second and lower layer of enamel. Dentin is a relatively hard mineral tissue composed of dentin tubules. 

The dentin is bright yellow, semi-transparent, and sensitive to pain. Dentin has a supporting role and supports enamel and pulp. Dentin also helps transmit light to the enamel and determines the color of the tooth.

  • Pulp

The pulp is the third and innermost layer of the tooth crown. Pulp is a soft and sensitive tissue that consists of connective tissue, blood vessels, nerves, and pulp cells. 

This layer is bright red, invisible, and very sensitive to pain and has the role of nutrition and protection and nourishes and protects the dentin. Pulp also has a production role and produces new dentin in case of dentin damage.

  • The root collar (Dental Cervix neck

the part connecting the crown and the root in the anatomy of the tooth

The neck of the tooth is one of the important parts of the anatomy of the tooth, which is located under the gums. The neck consists of two layers: pulp and gum.

    • pulp

The pulp is the layer inside the neck of the tooth that originates from the development of the crown pulp. The neck pulp has the same characteristics and functions as the crown pulp.

    • gum

The gum is the outer layer of the neck of the tooth, which consists of pink fleshy tissue. The gums are pink, visible, and sensitive to pressure. The gum has the role of covering and protection and covers and protects the neck and periodontal ligament.

  • Root

the lower part of the tooth in the jaw and dental anatomy

The root of the tooth is another main part of the anatomy of the tooth, which is located in the lower part of the tooth and in the jawbone, which connects the tooth to it. 

The root consists of three layers: cementum, periodontal ligament, and jaw bone.

  • Cementum

Cementum is the outermost layer of the tooth root. Cementum is a relatively soft mineral tissue composed of hydroxyapatite crystals. Cementum is bright white, invisible, similar to bone. Cementum plays a connecting role and connects the root to the periodontal ligament and jaw bone.

  • Periodontal ligament

The periodontal ligament is the second and lower layer of the cementum. The periodontal ligament is a connective tissue and collagen fiber that consists of connective tissue, collagen fibers, nerves, and blood vessels. The periodontal ligament is dark pink, invisible, and sensitive to pressure. 

The periodontal ligament has the role of connection, nutrition, and protection, and connects the root to the jaw bone, nourishes and protects the cementum.

The periodontal ligament also has a controlling role and controls chewing force.

  • Jaw bone

    The jaw bone is a hard bone tissue that consists of bone cells and mineral and organic materials. The white jawbone is gray, invisible, and contains dental cavities.

The jawbone has a supporting and shaping role supports the teeth and gums and helps shape the face.

As we have already said, the bones must have the necessary density to play their role. And this is a process that requires care. The jaw bone is not excluded from this story and we may lose it due to reasons such as gum disease and aging. So it is important to know How To Stop Facial Bone Loss? To support the proper performance of its duties. Because sometimes it may be impossible to rebuild Jawbone Loss Naturally after losing it and you have to undergo surgery.

Among the permanent teeth, there are 16 in the upper jaw and 16 in the lower jaw. Human permanent teeth are numbered in the order of the Bostrophydon sequence. Upper jaw teeth include:

  • Central teeth (teeth 8 and 9)
  • Lateral teeth (7 and 10)
  • teeth, bite (6 and 11)
  • First premolar (5 and 12)
  • second premolar (4 and 13)
  • First molar teeth (3 and 14)
  • Second molar teeth (2nd and 15th)
  • Third molar teeth (1 and 16)


The lower jaw also has the following teeth:

  • central teeth (24 and 25)
  • Lateral teeth (23 and 26)
  • canines (22 and 27)
  • First premolars (21 and 28)
  • second premolars (20 and 29)
  • First molar teeth (19 and 30)
  • Second molar teeth of the lower jaw (18 and 31)
  • Third mandibular Asian teeth (17 and 32)

Diseases, disorders, and common problems of teeth

  • Dental cavities and holes

    Cavities and decay are some of the most common dental diseases caused by the activity of bacteria and acidification of the oral environment on the surface of the teeth. These holes may be one of the causes of dental pain, inflammation, abscesses, fractures, and tooth loss.

The stages of tooth decay can be different based on the penetration of the cavities into the dental layers. In the early stages, it is very important to prevent the spread of decay. And if you suffer from enamel decay, you should know How To Cure Tooth Decay In Its Early Stage?. Because Tooth Decay From The Inside will occur with the infection of tooth pulp.

To prevent cavities and decay, you should pay attention to oral hygiene every day and use brushing, flossing, and eating healthy foods. To treat tooth cavities and holes, you must visit a dentist and use filling, restoration, crowning, or tooth extraction methods.

  • Pulpitis

    Pulpitis is an inflammation of the dental pulp that usually occurs as a result of damage to the tooth enamel or dentin. This inflammation may cause severe pain, swelling, fever, chills, and tooth sensitivity to cold or heat. In the article “Why Is Pulpitis More Painful At Night?” We have examined the pain and treatment caused by pulpitis.

To prevent pulpitis, damage to the teeth should be avoided and teeth protection, fluoride, and healthy foods should be used. To treat pulpitis especially Treatment For Chronic Hyperplastic Pulpitis, you should see a dentist and use the methods of root canal, pulpectomy, pulpotomy, or tooth extraction.

  • Periodontal disease

    Periodontal disease is an inflammation of the gums and tooth-supporting tissues that occurs due to the accumulation of plaque and tartar on the tooth surface or under the gums. This disease may cause bleeding, redness, swelling, pain, and tooth loss.

To prevent periodontal disease, you should practice daily oral hygiene and use brushing, flossing, and eating healthy foods. In that regard it is essential to know Best Toothpaste To Reverse Cavities. You should visit a dentist to treat gum and tooth problems and use cleaning methods, gum surgery, prosthetics, or implants.

Related: “What Is The Cause Of Tooth Decay Despite Brushing?

  • Mal occlusion

    Malocclusion means that the teeth and jaws are not right on top of each other. This unevenness may cause pain, wear, fracture, bursting, pressure, and tension on the teeth, gums, jawbone, and joints.

To prevent malocclusion, one should avoid bad habits such as finger sucking, keeping the tongue in front of the teeth, automatic chewing, and using treatment methods such as beautification, jaw surgery, or tooth restoration.

  • Bruxism or teeth-grinding

    Bruxism or teeth grinding is the pressure or grinding of the teeth unconsciously while awake or asleep. This habit may cause wear, fracture, bursting, sensitivity, pain, and inflammation of the teeth, gums, jaw bone, and joints.

To prevent teeth grinding or bruxism, you must find and eliminate the cause and avoid things that aggravate it such as stress, anxiety, anger, pain, or some medications and visit the dentist regularly and use treatment methods such as dental protection (night guard), proper nutrition, breathing exercises.ثس

Factors Affecting Dental Health

Several factors including diet, hygiene, genetics, and environmental factors can affect the health of teeth.

  • Diet

    A diet high in sugar and carbohydrates can lead to dental problems such as tooth decay. In addition, consuming acidic foods and drinks can erode tooth enamel and lead to sensitivity and other dental problems.

  • hygiene

    Poor dental hygiene, such as frequent brushing and flossing, can lead to plaque and tartar build-up, increasing the risk of tooth decay, gum disease, and other dental problems.

  • Genetic factors

    Some people may be genetically predisposed to dental problems such as tooth decay and gum disease. In addition, genetic factors can affect the size, shape, and structure of teeth and make them more susceptible to dental problems.

  • Environmental factors

    Environmental factors such as fluoride exposure, smoking, and medication can also affect dental health. Fluoride exposure can strengthen tooth enamel and prevent tooth decay, while smoking can increase the risk of gum disease and other dental problems.


What should be done to take care of the teeth?

Dental care: The most important parts of the face and body are the teeth. Healthy and tidy teeth not only protect the body’s immunity but also make the person’s face and smile look more beautiful. That is why dental care is very important and everyone must follow its tips.

Dental care includes tips before treatment or after treatment.

The passage of time and, naturally, the increase in lifespan has a direct effect on the health of teeth, so aging is one of the causes of tooth decay

On the other hand, some many factors and disorders occur at a young age and if they are not taken care of in time, they cause the loss of teeth.

Losing teeth disrupts the order of the body and causes many problems for the patient, including digestive problems such as not chewing well and digesting food. 

Also, the absence of teeth or decay, which is accompanied by the blackening and yellowing of the teeth, causes the loss of facial beauty and self-confidence.

To have white and beautiful teeth, you must follow the dental care tips daily and carefully. Otherwise, you will not only lose the beauty of your face but also cause many oral and dental diseases, including decay and gum infection.

Maybe it has happened to you that after your teeth are dark and stained, you decide to have white and shiny teeth like Hollywood actors. For this decision, you must first know What Are The Best Teeth-Whitening Methods? And in the next step to the question “What Is The Longest Lasting Teeth Whitening?” Have a convincing answer.

But in any case, to avoid getting into trouble and having to spend time and money to whiten your teeth, it is better to think about prevention.

The following requirements will help you:

  1. Be sure to brush your teeth before going to bed
  2. Use fluoride toothpaste
  3. Tongue and gum hygiene should be observed
  4. Using dental floss
  5. 5) Using mouthwash
  6. Drinking plenty of water
  7. Increasing consumption of fruits and vegetables
  8. Reduce consumption of sugary foods
  9. No smoking
  10. Visit the dentist regularly


Humans, like other mammals, are diphodonts, meaning they have two sets of teeth. The first set of teeth (called the baby’s primary or baby teeth) usually begins to appear at around six months of age, although some babies are born with one or more visible teeth. Humans have four types of teeth, each of which has a specific function

  Knowing the different types of teeth and their function is necessary to maintain proper dental hygiene and prevent dental problems. By observing proper dental hygiene and visiting the dentist regularly, people can have healthy teeth and maintain their overall health.

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Author and specialist

Dr. Majid Zahrabi,


  • Board Certified Neurosurgeon
  • DHA certificate holder
  • Plantation certificate holder, France
  • Certified holder of Discogol, France
  • A pioneer in the non-surgical treatment of disc herniation in the Middle East and CIS countries.
  • Under the training and coaching of Professor Jacques Theron (founder of Discogel Therapy) since 2008
  • More than 400 successful cervical and 1300 lumbar discogel injections
  • Trained and certified several neurosurgeons and spine surgeons in the Middle East and CIS countries for the treatment of Discogel
  • Strong belief in patient-centered care planning and participation
  • Neurosurgeon and spine surgeon at Imam Khomeini and Amir Mazandarani Hospital, Sari, Iran, with more than 430 surgeries annually, 2000-2011
  • Neurosurgeon and spine surgeon at Farmaniyeh, Nikan and Yas Sepid Hospital, Tehran, Iran, with more than 400 surgeries annually, 2011-2012
  • Neurosurgeon at Iranian Hospital, Dubai, 2022-2023
  • Since 2015, he has been working as a reference doctor for the treatment of intervertebral disc herniation with Discogel and has trained many doctors of spine-related specialties in various countries of the Middle East and CIS in person/practically and online.



  • Individual training sessions under the direct supervision of Professor Jacques Theron in Discogel treatment, 2008-2020
  • Training sessions under the supervision of Professor Thierry Boye on spinal implants, 2007
  • Participation and presentation in several national and international medical and neuro-spinal conferences
  • Board certificate by Iran Neurosurgery Board, 2001
  • Neurosurgery assistant training course, Isfahan University of Medical Sciences, Isfahan, Iran, 1996-2001 (In 2001, he graduated from Isfahan University of Medical Sciences with the first rank in the country.
  • His thesis the titled:The Application of human amniotic membrane in repair of dura matter in dogs.” ( It was happening for the first time in the world. )
  • General medical education, Tabriz University of Medical Sciences, Tabriz, Iran, 1984-1993


Published books:

  • CT scan of the brain for doctors
  • Etiology and treatment of painful spine disorders
  • Atlas of diagnosis, prevention, and treatment of spine disorders
  • The most common mistakes in the treatment of spinal disorders
  • Reading brain CT scan in simple language (3rd place in the book of the year)
  • Treatment of head and spine injuries

Publications and articles:

  • Bacteriostatic and bactericidal effects of DISCOGEL® (https://www.researchgate.net/)
  • Muscle recovery, reduction of pain, and improvement of movement strategies in patients with lumbar discopathy after injection of Discogel.
  • The article on the initial results of the treatment of intervertebral disc herniation with discogel injection, which won the second-best poster rank at the Pan Arab International Congress of Interventional Radiology (March 14-16, 2015) and was accepted for presentation at the Chicago Pain Congress.
  • The use of human amniotic membrane in dura mater repair in dogs, a study for the first time in the world.



  • Annual Congress of Physiotherapists of Iran, 2019
  • Chicago International Pain Congress, 2019
  • Iran International Pain Management Congress, 2018
  • Annual Congress of Physiotherapists of Iran, 2018
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Armenia for orthopedic specialists and neurosurgeons, 2017
  • First Live Workshop and Seminar on Minimally Invasive Disc Therapy (DISCON), 2017
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Azerbaijan for orthopedic specialists and neurosurgeons, 2016
  • Seminar of Iranian official managers, 2016
  • Presentation of Discogel as an innovative solution for the treatment of spinal disc herniation in Tajikistan for orthopedic specialists and neurosurgeons, 2016
  • International Neurological Intervention Congress in Iran, 2014
  • Educational seminar for nurses on treatment approaches for head and spine trauma, 2014
  • Educational seminar for general practitioners on treatment approaches for head and spine trauma, 2014
  • Speech at the Retraining Seminar for General Practitioners and Specialists in Dubai (Discon) in 2017
  • Speech in the internal retraining courses of Irani Hospital, Dubai
  • Holding lecture sessions and practical workshops on the treatment of intervertebral disc herniation with discogel injection in Azerbaijan, Tajikistan, Ukraine, Oman, and Armenia during the years 2015 to 2021.
  • Giving a lecture and holding a practical workshop for neurosurgeons in Vietnam at Ho Chi Minh City University in 2023

Dr. Majid Zohrabi started treating his patients in Dubai in 2022 and continues his activities in private medical centers in the UAE.