Dental caries disease, also called tooth decay, refers to demineralization or weakening of the teeth, and the end result of caries disease is a caries lesion.
An advanced caries lesion can progress to a point where the tooth surface forms a cavitation or a hole, which is the physical evidence of tooth breakdown.
Let's start by building a model of a tooth and its surrounding structures.
In the mouth, the bone beneath the bottom row of teeth is the mandible, and the bone above the top row of teeth is the maxilla.
Both bones have an alveolus, or socket, for each tooth.
The socket is lined on the inside by a periodontal ligament.
Protecting the alveolus on the outside, is a layer of soft, supportive tissue called the gingiva, or gums, that sits on top of the bone and covers the root surface from the bone to the cementoenamel junction - where the cementum and enamel come together.
The tooth itself can be roughly divided into a few parts.
The first part is the root, and it sits within the alveolus.
The root is covered by cementum, which is a bonelike substance that the periodontal ligament’s fibers attach to.
Next, there’s the neck, which is the transition between the root portion covered by bone and the crown.
The crown is the visible part of the tooth that protrudes from the gingiva, and it’s covered in enamel, which has such a high mineral content that it’s the hardest substance in the human body.
When the teeth are developing, enamel is made before the tooth erupts into the mouth by a group of cells called the ameloblasts that die once the tooth erupts - meaning that the teeth lose the ability to make more enamel forever.