What is the structure of a tooth?
A tooth is a living organ, made of hard and soft tissues and anchored in the jaw, that makes chewing, speaking and smiling possible.
Understanding tooth structure helps explain why problems such as decay and sensitivity develop, and what each dental treatment is trying to achieve.
The main parts of a tooth
A tooth has three main parts: the crown, the neck and the root.
Crown
The crown is the visible part of the tooth above the gum line, covered with enamel, the hardest substance in the human body.
Neck
The neck joins the crown to the root, where the tooth meets the gum.
Root
The roots are anchored deep in the jawbone and give the tooth the stability it needs to withstand chewing and biting forces.
The layers of a tooth: enamel, dentin and pulp
The enamel covering the crown is made mostly of hydroxyapatite, a calcium-rich mineral. Despite its strength, enamel contains no living cells and cannot regenerate once it is damaged (Lacruz et al., 2017), which makes protecting it essential.
Under the enamel lies the dentin, hard but less hard than enamel, which makes up most of the tooth. Dentin contains tiny tubules that lead to the pulp: when dentin is exposed, heat, cold, or sweet or acidic foods stimulate the nerves inside the tooth through these tubules. This explains the sensitivity that develops when enamel wears away or when receding gums expose the root.
In the center of the tooth is a chamber containing the pulp, the living part of the tooth, with nerves, blood vessels and connective tissue. The pulp supplies oxygen and nutrients, removes waste and produces the pain that warns of a problem. When the pulp is damaged by deep decay or an injury, root canal treatment may be needed to save the tooth.
| Tissue | Location | Key features |
|---|---|---|
| Enamel | Covers the crown | Hardest substance in the body; cannot regenerate once damaged |
| Dentin | Under the enamel | Hard but less hard than enamel; makes up most of the tooth; contains tubules leading to the pulp |
| Pulp | Center of the tooth | Living tissue with nerves, blood vessels and connective tissue |
The shape of each tooth directly affects treatment options: the anatomy of the root canals varies a lot between incisors, canines and molars, which calls for a tailored approach to root canal treatment and full mouth rehabilitation.
The supporting tissues of the tooth (periodontium)
Beyond its main parts, each tooth is surrounded by a support system called the periodontium: the gums (gingiva), the alveolar bone, the cementum and the periodontal ligament. The gums form a seal around the tooth, keeping bacteria out of the deeper tissues and protecting the supporting bone from infection.
Cementum and periodontal ligament
Cementum is a thin layer of hard tissue covering the root, which anchors the fibers of the periodontal ligament. The ligament, made of collagen fibers, attaches the tooth to the bone and allows tiny movements within the socket, absorbing shocks during chewing.
Blood supply
The blood vessels and nerves of the pulp enter the tooth through a small opening at the tip of the root (apical foramen), while the ligament and bone have their own blood supply. After a dental injury, damage to the vessels at the root tip can affect the vitality of the pulp, which is why the dentist follows an injured tooth over time.
Examination, treatment plan and price quote
detailed and personalized
During the consultation, Dr Haim Aseriel examines your teeth, explains all the options and gives you a transparent price quote, with no obligation. The clinic is at 12 HaTnufa Street, Jerusalem.
When tooth structure changes
Modern restorative materials try to imitate the physical and aesthetic properties of natural enamel and dentin, although their properties are still not identical.
Tooth structure can be altered by decay, injury, wear, grinding and acid erosion. Regular check-ups, with X-rays when indicated, detect these changes before they cause symptoms, and a broken tooth can be restored with broken tooth repair.
Types of teeth and their functions
Teeth develop from before birth into adulthood, and each type is shaped for a specific job: incisors cut, canines tear and molars grind. An adult has up to 32 permanent teeth, 16 in each jaw, each shaped for a specific role in biting, tearing or grinding.
01
Incisors
Four upper and four lower incisors at the front of the mouth, thin and flat with a cutting edge. They are the first teeth to erupt in babies, and the upper central incisors shape the first impression of a smile.
02
Canines
Two upper and two lower canines at the corners of the mouth, with long, strong roots, used to tear food. Because of their role in the dental arch, dentists try hard to preserve them.
03
Premolars
Four upper and four lower premolars behind the canines, usually with two cusps (sometimes three). They help tear food like the canines and start crushing it like the molars.
04
Molars
Three molars on each side of each jaw: 12 in total, including the four wisdom teeth (third molars). With a broad chewing surface and several roots, they do most of the grinding. The first permanent molars erupt around age 6, the second around age 11 to 13.
Tooth names and numbers
Dentists use a numbering system to identify each tooth precisely. In Israel, as in most countries, dentists use the FDI system, which divides the mouth into four quarters and gives each tooth a two-digit number: the first digit is the quarter (1 to 4), the second the position of the tooth in that quarter. In the United States, dentists usually use the Universal Numbering System, which numbers permanent teeth from 1 to 32, so your dental records from the US may look different.
In the FDI system, baby teeth are numbered in quarters 5 to 8. Children usually start losing baby teeth around age 6 to 7, when the first permanent molars erupt behind the baby molars; the exchange is usually complete around age 12 to 13, apart from the wisdom teeth.
17-21 years
Usual age range for wisdom teeth to erupt
Wisdom teeth are the third molars, numbered 18, 28, 38 and 48 in the FDI system. They are the last to erupt, usually between ages 17 and 21, and there is often not enough room for them. The decision on wisdom teeth removal is based on an examination and X-ray, not on age alone.
Dr Haim Aseriel, a US-trained dentist (DDS, NYU College of Dentistry), takes the time to explain your teeth and X-rays in English before any treatment. The clinic is at 12 HaTnufa Street in Talpiot, south Jerusalem, open Sun 8:00–19:00 · Mon 9:00–19:00 · Tue–Wed 9:00–21:00 · Thu 8:30–21:00 · Fri 8:00–14:00.
Tooth structure: frequently asked questions
A tooth has three main parts: the crown, the neck and the root. The crown is the visible part above the gum line, covered with enamel, the hardest substance in the human body. The neck joins the crown to the root at the gum line. The roots are anchored deep in the jawbone and give the tooth the stability it needs to withstand chewing and biting forces.
The pulp is the living tissue in the center of the tooth, containing nerves, blood vessels and connective tissue. It supplies the tooth with oxygen and nutrients, removes waste and produces the pain that warns of a problem. When the pulp is damaged by deep decay or an injury, root canal treatment may be needed to save the tooth.
No. Enamel is made mostly of hydroxyapatite, a calcium-rich mineral, and contains no living cells, so it cannot regenerate once it is damaged by decay, wear or erosion. This is why protecting enamel is so important for long-term oral health.
The supporting tissues of a tooth, called the periodontium, hold it in the jaw. They include the gums (gingiva), the alveolar bone, the cementum that covers the root, and the periodontal ligament that attaches the root to its bony socket.
Each type of tooth has its own role: incisors cut food, canines tear it, premolars tear and crush it, and molars grind it. An adult has up to 32 permanent teeth: 8 incisors, 4 canines, 8 premolars and 12 molars, including 4 wisdom teeth.
Sources
- ADA MouthHealthy, Tooth – View the page
- Lacruz RS et al., Physiological Reviews, 2017 – View the study
- American Dental Association, Permanent Tooth Development, 2012 – View the document
- ADA MouthHealthy, Wisdom Teeth – View the page
