When most people think about their teeth, they focus on brushing and flossing routines, straightness, or whitening treatments. But beneath the surface, teeth are complex anatomical structures, each with distinct parts and roles. Understanding the biology of your teeth isn’t just academic—it’s essential for maintaining healthy teeth and long-term oral health.
At Legacy Smiles, we believe that informed patients make better choices for their dental care. This article breaks down the parts of a tooth, the number of teeth humans have throughout life, and how each component plays a role in your oral well-being.
How Many Teeth Do Humans Have?
Most adults have 32 permanent teeth, including wisdom teeth. These are divided as follows:
- 8 incisors (4 upper, 4 lower) – the sharp front teeth for cutting food
- 4 canines (2 upper, 2 lower) – pointed teeth used for tearing
- 8 premolars – transitional teeth for grinding
- 12 molars – large back teeth for chewing, including 4 wisdom teeth
However, not everyone retains all 32 teeth. It’s common for people to have 28 teeth if wisdom teeth have been extracted or never developed. According to the American Association of Oral and Maxillofacial Surgeons, about 85% of wisdom teeth will eventually need removal due to impaction or crowding.
In contrast, children have 20 primary teeth, which start erupting around six months of age and are typically all present by age three. These “baby teeth” begin to fall out around age six, making room for permanent teeth.
Parts of a Tooth: Breaking Down the Anatomy
Teeth may appear simple on the outside, but they are composed of several layers and structures, each serving a unique function. A complete understanding of the parts of a tooth helps clarify how dental diseases form—and how to prevent them.
Enamel
What it is: The outermost layer of the tooth
Composition: 96% mineral (mostly hydroxyapatite), making it the hardest substance in the human body
Function: Protects the tooth from physical wear and acid erosion
Important note: Enamel contains no living cells, so it cannot regenerate once damaged
Fluoride helps strengthen enamel by forming fluorapatite, which is more resistant to acid attacks. That’s why fluoride use is a cornerstone of preventive dentistry at Legacy Smiles.
Dentin
What it is: The layer beneath the enamel
Composition: About 70% mineral and 30% organic material and water
Function: Supports the enamel and carries sensations (such as heat or cold) through microscopic tubules
If enamel erodes or cavities form, dentin becomes exposed, often causing sensitivity. According to the Journal of Clinical Dentistry, dentin hypersensitivity affects 10–30% of the population.
Pulp
What it is: The innermost layer of the tooth
Composition: Soft tissue made up of nerves, blood vessels, and connective tissue
Function: Supplies nutrients to the tooth and responds to stimuli (pain, pressure, temperature)
If bacteria reach the pulp, infection can occur, requiring a root canal to preserve the tooth. Maintaining the outer layers of the tooth helps avoid pulp exposure and the associated complications.
Cementum
What it is: A calcified layer covering the root of the tooth
Function: Anchors the tooth to the jawbone via the periodontal ligament
Vulnerability: Can be damaged by aggressive brushing or gum disease
Cementum is softer than enamel and more vulnerable to wear and decay once exposed, especially in cases of gum recession.
Periodontal Ligament
What it is: A group of connective tissue fibers that attach the tooth to the alveolar bone (jawbone)
Function: Acts as a shock absorber during chewing and helps stabilize the tooth in its socket
The health of this ligament is essential for healthy teeth, as its deterioration is a key marker of periodontal disease, which affects nearly 47% of adults over age 30 in the United States, according to the CDC.
Types of Teeth and Their Functions
Teeth are not uniform—each type plays a distinct role in digestion and oral function.
Incisors (8 total): Cutting food
Canines (4 total): Tearing food
Premolars (8 total): Crushing and grinding
Molars (12 total): Chewing and mashing
A balanced bite depends on all these tooth types working together. Losing even one molar can alter chewing efficiency, affect speech, and shift neighboring teeth out of alignment, compromising long-term oral health.
The Role of Teeth in Oral and Systemic Health
While teeth are localized to the mouth, their health has systemic implications. Poor oral health, particularly if tied to decay or gum disease, can influence broader medical outcomes.
Links Between Tooth and Systemic Disease
- Cardiovascular health: Gum disease has been linked to increased risk of heart disease due to systemic inflammation
- Diabetes: Poor oral health can exacerbate blood sugar control, and vice versa
- Pregnancy complications: Periodontitis has been associated with low birth weight and preterm births
The parts of a tooth—from enamel to the periodontal ligament—are all susceptible to these systemic effects, especially when oral bacteria enter the bloodstream.
How to Maintain Healthy Teeth
Prevention is central to keeping all parts of the tooth intact. At Legacy Smiles, we advocate for a comprehensive care routine rooted in the latest research.
Proper Brushing and Flossing
Use a soft-bristled toothbrush and fluoride toothpaste twice daily. Flossing once daily helps remove plaque from between teeth and under the gumline—areas where toothbrushes can’t reach.
Dietary Habits
Limit intake of acidic and sugary foods. Frequent snacking can maintain acid levels in the mouth, eroding enamel. Choose foods rich in calcium, phosphorus, and vitamin D to support enamel remineralization.
Regular Dental Visits
Routine checkups and cleanings help monitor wear on enamel, early signs of decay, or gum disease. X-rays and professional evaluations at Legacy Smiles allow us to detect issues before they escalate.
Protective Gear
If you grind your teeth (bruxism) or play contact sports, wear a mouthguard to prevent mechanical damage to enamel and underlying structures.
Fluoride Treatments
Professional fluoride varnishes or at-home rinses can help remineralize enamel and strengthen vulnerable areas of the tooth.
When Things Go Wrong: Common Dental Issues by Tooth Structure
Each part of the tooth can be affected by specific conditions:
- Enamel: Susceptible to erosion and cavities
- Dentin: Exposure leads to sensitivity
- Pulp: Infection or inflammation can require root canal therapy
- Cementum and Ligaments: Vulnerable to periodontitis and trauma
Understanding which parts of a tooth are impacted helps guide treatment. At Legacy Smiles, our treatment plans are customized based on the specific structure affected and the severity of the issue.
Future Research: Enamel Regeneration and Beyond
While current dental practices focus on preserving existing tooth structure, emerging research is exploring tooth regeneration. In 2023, researchers at Kyoto University announced successful trials of a drug that could stimulate the growth of new teeth in mice, aiming for human clinical trials by 2030.
In the meantime, the best strategy for preserving healthy teeth remains proactive care and a strong understanding of anatomy.
Conclusion: The Anatomy of a Lifetime Investment
Your teeth are more than tools for chewing—they’re complex anatomical structures vital to nutrition, communication, and systemic health. Knowing the parts of a tooth—enamel, dentin, pulp, cementum, and periodontal ligaments—can help you take proactive steps to protect them.
At Legacy Smiles, our mission is to preserve and enhance your oral health through science-backed care, detailed diagnostics, and education. Whether you’re looking to maintain healthy teeth, address a specific concern, or learn more about how teeth function, our team is here to guide you.
If it’s been a while since your last dental exam, schedule a visit today. Your teeth—and every layer within them—will thank you.
Sources
- Centers for Disease Control and Prevention (CDC). “Oral Health Surveillance Report 2019.”
- American Dental Association. “Tooth Anatomy.” ada.org
- Journal of Clinical Dentistry, Vol. 27, Issue 1
- Kyoto University. (2023). “Drug Treatment Shows Promise for Tooth Regeneration in Mice.”
- American Association of Oral and Maxillofacial Surgeons. “Wisdom Teeth Facts.”
- National Institute of Dental and Craniofacial Research. “Dental Caries and Tooth Loss”
