If someone asks you how many teeth do you humans have? Then the most accurate answer would be – it depends on the age group. Children and adults have different types of teeth. The number of teeth also varies. Children have 20 teeth, whereas adults have 32 teeth (including 4 wisdom teeth).
But do you know that the teeth developments begin in the fetal stage itself? Proper nutrition from the mother at the time of pregnancy is the stepping stone which determines our oral health.
And hence pregnancy diet should have adequate amounts of calcium, vitamin D, and vitamin C. Certain medications such as tetracycline taken during pregnancy can cause permanent discoloration of the developing teeth of the embryo.
So before you visit the dentist next time, have a basic knowledge about your teeth for a better understanding of the dental procedures. Let’s find out how many teeth do kids have.
Diphyodont teeth set
Human beings are diphyodont mammals, as they get two successive sets of teeth (1). The first set is called the deciduous set, also known as the milk teeth or the baby teeth.
The second set is called permanent set that erupts after the deciduous teeth fall out. As an infant, our mouths are too small to accommodate a full set of permanent teeth.
Deciduous teeth maintain the space until our jaw can accommodate the permanent set. As the adult teeth form, specialized cells in our mouth called odontoclasts absorb the roots of the baby teeth.
When your adult teeth start to emerge from your gums, the deciduous teeth have no roots and hence no anchorage making them loose and able to easily fall out.
Children begin teething around the age of six months. The term for these early teeth is deciduous teeth because they eventually shed out. Most people know these teeth as the baby teeth, sometimes called milk teeth or primary teeth.
Children have 20 baby teeth – 10 in the upper jaw called the maxillary teeth, and 10 in the lower jaw called the mandibular teeth. The primary teeth set comprises 8 incisors, 4 canines, and 8 molars. Around six years of age, most children begin to lose their baby teeth, and this process will continue until their early teens.
Taking proper care of primary teeth is essential as a decay in primary teeth can cause infection which can travel down to the developing permanent teeth.
Premature exfoliation or removal of the primary teeth can lead to loss of space (2), the permanent teeth won’t have a proper guide for the eruption and this can lead to crowding of the teeth.
Let’s find out how many teeth do adults have?
Adult teeth are also called succedaneous teeth as they erupt succeeding the primary teeth. Adults have more teeth than children; most adults have 32 teeth. Upper and lower jaw contain sixteen teeth each in most cases.
Among these teeth are 8 incisors, 4 canines, 8 premolars, and 12 molars including 4 wisdom teeth. Around the age of fourteen- sixteen most adults get complete set of permanent teeth.
The third molar also is known as the wisdom teeth start erupting post the age of seventeen years. Some people have congenitally missing teeth and the tooth count in such individuals will be less (3).
Classification of teeth
A human tooth can be divided into two sections. The visible portion of the tooth above your gum line is called the crown portion of the tooth.
The part of tooth seated in the bone is called the root portion of the tooth. A tooth can be single rooted or can have multiple roots, depending on their location and anatomy.
Based on their anatomy and function, we can divide the teeth set into four major categories.
The front 4 teeth, in both upper and lower jaw, are the incisors. The two set of teeth on either side of the midline are called central incisors, the tooth next to the central incisors are the lateral incisors.
Incisors are used for biting on food, and its chisel edge has been adapted for cutting (4). In the deciduous teeth set, the mandibular central incisors erupt first around six months of age which is followed by the maxillary central incisors, then the mandibular lateral incisors and finally the maxillary laterals.
Around six years of age, the lower mandibular central incisors are the first the exfoliate.
Canines are called the cornerstone of our dentition(5). They are the third teeth from the center. Canines are your sharpest teeth and are used for ripping and tearing food apart. They have a single cusp which aids in holding and shearing of food.
Primary canines appear around 16 and 20 months, the maxillary canines coming in just ahead of the mandibular canines. In permanent teeth, the order is reversed, the mandibular canines erupt around the age of 9 years, and the maxillary canines erupt between 11 to 12 years of age.
Premolars as the name suggests, are located before molars. Also known as bicuspids, because of the presence of two cusps (6), premolars are absent in the primary dentition and erupt around the age of ten years.
They are four in number both in the maxillary jaw and mandibular jaw. The four premolars are located two on each side between canines and molars. Premolars are mostly used for chewing and grinding food.
Molars are the main teeth of mastication. Primary molars, appear between 12 and 28 months. The premolars succeed the deciduous molars. The permanent molars do not replace any of the primary teeth.
The first permanent molars erupt around the age of six years while the second molars erupt in between 11 to 13 years of age. The molars do the mastication, chewing and grinding process of our food (7).
The third molars are also commonly known as the wisdom teeth. They are paired tooth and erupt as the last tooth behind the second molars in the maxillary and mandibular jaw.
Third molars or the wisdom teeth are the last teeth to erupt, around 18 to 20 years of age (8). Some people never develop third molars at all. They do not aid much in any process of mastication, and many cases are impacted.
Most people require surgical removal of the impacted wisdom teeth (9).
Parts of your teeth
Your teeth contain four different kinds of tissue, their function and structure classify them. As mentioned, Our teeth have a crown and root portion. The crown portion compromises of enamel and dentin tissue.
The root portion contains cementum. The pulp tissue is common in both the crown and root portion of the teeth.
Enamel is the visible substance that covers the tooth crown. Enamel is the hardest structure in your body, even harder than the bone. It is brittle, and it protects the vital tissues within the tooth. Enamel also protects our teeth from sensitivity.
The composition of enamel is mostly hydroxyapatite, phosphorous, and calcium. The enamel is the whitest part of your teeth, and with age, it tends to wear off showing the yellow inner tissue, dentin.
Certain habits such as tobacco, drinking aerated drinks, aggressive brushing can cause premature wearing of enamel.
Underneath the enamel layer, you find dentin; Dentin is a bone-like structure but is softer than the bone. Dentin compromises of mostly two layers primary and secondary dentin.
A third layer known as tertiary dentin is placed in response to a stimulus. Dentin consists of microscopic tubules which contain dentinal fluid. The purpose of these channels is to carry sensations from the outer enamel to the inner pulp.
All three types of dentin are vital to the longevity of the tooth. Dentin is softer than the enamel, and hence if the enamel layer wears off, the dentin will be prone to decay. Just inside the dentin layer is the pulp, in cases of tooth decay or tooth structure wear, the stimulus can cause dentinal hypersensitivity (10).
Cementum covers the tooth root and aids in the anchorage of the tooth in the bone. Your gum tissue surrounds the cementum. With inadequate dental care, the gums may become diseased and shrink, exposing the cementum to harmful plaque and bacteria.
As it is softer than enamel and dentin, it can get decayed easily. Hence gum health is essential to protect cementum from getting decayed.
The pulp is the centermost core of your tooth. It compromises of blood vessels, nerves, and other soft tissues. Pulp has a smooth, gelatinous consistency. Dental pulp is not mineralized, and the majority of pulp (75-80%) is water.
The pulp cavity extends down through the root of the tooth as the root canal. The pulp cavity of a molar tooth is approximately four times larger than an incisor tooth. Due to decay or trauma, the pulp tissue gets inflamed and can cause intense pain.
So, how many teeth do you have?
Ideally, kids have 20 teeth and adults have 32 teeth (including 4 wisdom teeth). But this number largely depends on how you care for them. Human tooth tries to heal itself. But repeated trauma and improper dental hygiene can cause permanent decay and damage to the tooth.
Proper brushing and flossing habits should be started from an early age. Taking care of primary teeth is just as important as taking care of the permanent teeth.
Be regular with your dentist, if you take care of teeth, it can save your time and money. Fill out those small cavities before it goes for a root canal treatment. Do regular cleaning to avoid gum diseases.