---
title: "What Is Dentin? Dental Glossary | Town Center Dental"
description: "Dentin is the layer of a tooth that sits under the enamel and cementum. It makes up most of the tooth and contains tiny tubes that lead toward the nerve."
url: https://towncenterdental.multisites.ai/glossary/dentin
publisher: Town Center Dental
phone: +1-636-273-5866
quote: https://towncenterdental.multisites.ai/request-appointment
---

Anatomy

# Dentin

Dentin is the layer of a tooth that sits under the enamel and cementum. It makes up most of the tooth and contains tiny tubes that lead toward the nerve.

Dentin is the hard tissue that forms the bulk of a tooth. It lies under the [enamel](https://towncenterdental.multisites.ai/glossary/enamel) on the crown and under the [cementum](https://towncenterdental.multisites.ai/glossary/cementum) on the root. Dentin is softer than enamel. It also contains microscopic tubes, called tubules, that lead toward the [tooth pulp](https://towncenterdental.multisites.ai/glossary/tooth-pulp).

When enamel wears away or gums pull back, the tubes in dentin are exposed. Heat, cold, sweets or acids can then reach the nerve and cause a short, sharp twinge. This is a common cause of tooth sensitivity.

Dentin can also decay once a cavity reaches it. A dentist can check for decay at an exam and talk with you about next steps.

## Related terms

-   [Enamel](https://towncenterdental.multisites.ai/glossary/enamel)
-   [Tooth pulp](https://towncenterdental.multisites.ai/glossary/tooth-pulp)
-   [Cementum](https://towncenterdental.multisites.ai/glossary/cementum)
-   [Tooth sensitivity](https://towncenterdental.multisites.ai/glossary/tooth-sensitivity)
-   [Cavity (dental caries)](https://towncenterdental.multisites.ai/glossary/cavity-dental-caries)

## Sources

1.  [MouthHealthy (ADA): Tooth](https://www.mouthhealthy.org/all-topics-a-z/tooth)

## Ready when you are

[Request an appointment](https://towncenterdental.multisites.ai/request-appointment)[Call (636) 273-5866](tel:+1-636-273-5866)