permanent teeth

Everyone goes through the period of tooth eruption in life. It is fascinating to know that humans are born with two different sets of dentitions. The first set of teeth that erupt in the early childhood are referred to as the primary dentition or baby teeth. The successors of primary teeth are called as the adult teeth or permanent dentition.

Typically, permanent dentition consists of a set of 32 teeth – 16 teeth in each dental arch. These teeth are primarily guided into correct positions by the primary teeth in the mouth. Unlike primary dentition, permanent teeth cannot be replaced naturally. Once lost, an artificial dental crown or bridge can only replace them. Therefore, it is essential to always take extra care of the permanent teeth.

Let’s read this interesting article and know more about your precious pearly white permanent teeth. We are going to discuss about the importance, functions, and eruptions sequence of the permanent dentition.

What do you mean by permanent dentition?

Permanent teeth are commonly referred to as adult teeth. This dentition forms the second set of teeth in the humans. This is the reason why human beings are considered as diphyodonts – which means born with two sets of teeth.

Permanent dentition typically consists of 32 teeth in total – 16 teeth in each dental arch. Each toot has a specific structure and function. However, together, all the permanent teeth aid in proper digestion, speech, and overall appearance of the smile. (1) To breakdown the division of permanent teeth, there are typically four types of teeth that form the permanent dentition –

  • Four incisors on each dental arch
  • Two canines on each dental arch
  • Four premolars on each dental arch
  • Six molars on each dental arch

As compared to the primary teeth, permanent teeth have thicker enamel, dense tooth roots, and more prominent crown structure. All these characteristics contribute to defining the smile of a person.

What is the importance of permanent teeth?

Permanent teeth are the last set of teeth that erupt in the mouth. They are typically the long-lasting teeth that aids in chewing, speaking, and swallowing. Moreover, permanent teeth play a significant role in maintaining the appearance of the smile. Unlike the primary dentition, permanent teeth cannot be replaced by a natural tooth.

However, it can be replaced by cosmetic dental prostheses such as a dental crown, bridge, or denture. It is therefore, essential to take extreme care in maintaining the health of the permanent teeth. (2) Any damage to these teeth may lead to a series of oral health problems. Moreover, it can significantly impact the aesthetics of the smile.

What are the functions of permanent teeth?

Typically, permanent teeth play a crucial role in the following aspects –

  • Aids in digestion by allowing the proper breakdown of the food particles and formation of the food bolus in the mouth.
  • Helps the individual in speaking.
  • Provides a white and bright smile which is considered as one of the most attractive features of the face.
  • Helps in swallowing the food.
  • Presence of teeth gives a characteristic dimension to the facial profile of an individual.

As mentioned above, every tooth in the permanent dentition has its own unique set of functions that help to simplify the process of digestion and speech. Some of the primary purposes of each permanent tooth are listed below –

Incisors

Incisors are typically characterized as the front teeth in the mouth. Both the upper and lower arch consists of two central and two lateral incisors. Usually, incisors have a chisel shape with sharp edges that help to cut the food or bite on the food substance. This action can be seen while biting a piece of apple with the teeth. Incisors are also the main attraction to a person’s smile. Proper shape and size of incisors can significantly impact the look of a person’s smile. Moreover, it boosts up their confidence and self-esteem.

Canines

Canines are the conical teeth that form the cornerstone of the smile. These teeth are located on either side of the lateral incisors in both the dental arches. The shape of the canine differs from that of the incisors. It consists of a pointed cusp instead of the incisal edge. Hence, canines are also called as cuspids. The unique pointed shape of the canine helps to tear the food into smaller pieces easily. This way canines establish the first step of digestion which his to breakdown the food into smaller particles. (3)

As mentioned above, canines act as at the cornerstone of a person’s smile. Rotated canines or forwardly placed canines can cause improper bite and also affect the aesthetics of the smile. Permanent canines are also considered as the second most commonly impacted tooth in the mouth.

Premolars

Premolars are a unique set of permanent teeth that are not found in the primary dentition. Typically, a permanent dentition consists of two pairs of premolars on the sides of the canine in both the dental arches. Premolars have a unique oval shape which forms as a result of two cusps on the occlusal surface. This is the reason why premolars are often referred to as bicuspids. Premolars are also one of the most prominent teeth as compared to the front incisors and canines.

The flat surface of the premolars often helps to crush the food completely in the mouth. Grinding of the food allows to breakdown the smaller pieces of food into soft chewable particles.

Molars

Molars are considered as the most bulbous and most comprehensive teeth in the mouth. These teeth are also one of the most prominent teeth in the oral cavity as compared to the premolars. Typically, a permanent dentition consists of three pairs of molars on each dental arch.

The first set of molars are usually the first set of permanent teeth that erupt in the mouth at the age of six years. The third molars are the last set of teeth to erupt in the mouth. Often the third molar teeth, also known as the wisdom teeth, are considered as the most commonly impacted teeth in the mouth. This happens due to lack of space in the jaw for proper growth and development. (4)

Molars consist of four to five cusps which broaden the occlusal table of the tooth and provides a broader area for grinding of the food. Just like the premolar teeth, molars are known for their crushing and grinding motions that completely break down the food particles and prepares it into a food bolus which is swallowed down the throat.

What is the eruption sequence for permanent teeth?

Typically, the permanent teeth begin to erupt at the age of six years. The first molars are the first set of permanent teeth that erupt in the mouth at this stage. (5)

Following is the eruption sequence of the permanent teeth for both the upper and lower dental arches –

Tooth Eruption Date
Maxillary
Central Incisor 7-8 Years
Lateral Incisor 8-9 Years
Canine 11-12 Years
1st Premolar 10-11 Years
2nd Premolar 10-12 Years
1st Molar 6-7 Years
2nd Molar 11-13 Years
3rd Molar 17-21 Years
Mandibular
Central Incisor 7-8 Years
Lateral Incisor 8-9 Years
Canine 9-10 Years
1st Premolar 10-12 Years
2nd Premolar 11-12 Years
1st Molar 6-7 Years
2nd Molar 11-13 Years
3rd Molar 17-21 Years

A note on permanent teeth disorders

Just like primary dentition, permanent teeth are also prone to common dental diseases that typically include tooth decay, cavity formation, tooth sensitivity, enamel erosion, and tooth loss. Dental plaque is one of the main culprits that initiates the process of tooth decay in the mouth. It develops as a sticky yellow layer of food debris and bacteria on the tooth surface. As the plaque accumulates, it eats away the tooth enamel and penetrates the underlying dentin and pulp.

This vicious cycle continues to weaken the tooth structure that progresses to the gums causing loss of support and resulting in tooth loss. Some other disorders of permanent teeth include –

  • Delayed tooth eruption because of premature primary tooth loss (6)
  • Impaction of third molars
  • Tooth discolorations
  • Development of weak tooth due to developmental disabilities, for example, amelogenesis imperfecta.
  • Tooth abscess

What factors influence the eruption of permanent teeth?

Several factors typically influence the eruption rate and sequence of the permanent teeth in the mouth. Some of these factors are listed below –

Genetic influence

Several scientific studies co-relate the genetic influence on permanent tooth eruption. Most commonly, genetic disorders lead to delay in the tooth-eruption pattern of permanent teeth. Typically, genetic diseases can be categorized into two types –

  • Genetic disorders that affect the formation of tooth follicle for example – amelogenesis imperfecta and hurler’s syndrome
  • Genetic disorders that interrupt the osteoclastic activity of the tooth, which helps the tooth to break free into the jaw. These disorders include cleidocranial dysplasia and osteoporosis.
  • Other disorders that can influence the eruption rate of permanent teeth include the formation of supernumerary teeth and gingival hyperplasia. (7)

Gender influence

It is typically seen that permanent teeth erupt at a faster rate in girls as compared of the boys. These differences are evident, especially during the eruption of upper lateral incisors, canines, and lower canines. Usually, the time difference between the eruption of these teeth in both the genders ranges between four to six months.

Nutritional influence

There is not much data that supports an evident impact of nutrition on the eruption rate of the permanent teeth. However, there is evidence that chronic malnutrition that extends beyond early childhood can cause discrepancies in the eruption sequence of the permanent teeth.

Hormonal influence

Usually, endocrine disorders can significantly impact the growth and development of several organs in the body, including the teeth. Several hormonal conditions like hypothyroidism, hypoparathyroidism, and hypopituitarism lead to the delayed eruption of the permanent teeth. In contrast to the disorders mentioned above, an increase in growth hormone factor can accelerate the eruption rate of permanent teeth. (8)

Socioeconomic factors

A clinical survey study revealed that children who are part of a higher socioeconomic family experience early tooth eruption. This is because of the presence of healthy nutrition and health care that allows proper growth and development of the permanent teeth.

Systemic illnesses

Our mouth reflects the underlying health conditions in the form of dental problems like gingival hyperplasia, fibromatosis, and other hormonal changes. Such situations often impact the eruption rate of the developing permanent teeth and cause a delay in the emergence of the teeth in the mouth.

Take away message

Our teeth are one of the most unique aspects of the mouth. They perform a lot of functions that includes speaking, chewing, and swallowing. More importantly, the teeth contribute significantly in giving us the attractive pearly white smile. Permanent dentition is considered as an essential component of the oral cavity. This is because there are no successor teeth that erupt after this dentition. Permanent teeth differ slightly from the primary teeth in terms of better strength, color, and structure.

Several factors influence the eruption rate of the permanent teeth. Some of these factors include genetic disorders, hormonal changes, gender influence, systemic diseases, and socioeconomic factors. It is essential always to increase the longevity of the natural smile. It not only saves a lot of time, money, and energy but also prevents painful dental conditions.