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Module 2: Dental Caries Process

2.3 Dental Caries Progression

Figure 3: Tooth Structure
Used with permission from Aetna InteliHealth.

To understand the caries process, it is important to have a basic understanding of the tooth and its structure. A tooth is composed of the crown and the root. The crown is visible in the oral cavity, and the root is below the gumline and anchors the tooth to the surrounding bone (see figure 3). Structures of the tooth include:

  • Enamel. Enamel is white in color and covers the crown of the tooth. It is the hardest substance in the body. The enamel layer in primary teeth is much thinner than the enamel layer in permanent teeth.
  • Dentin. Dentin is the underlying material that supports the enamel. It is a yellow bone-like material that is softer than enamel. Dentin also caries nerve fibers that are made up only of pain receptors.
  • Pulp. The pulp contains blood, lymph vessels, and nerve fibers, which nourish the tooth and transmit pain.
  • Cementum. Cementum is a bone-like layer that covers the root of the tooth. It serves to attach the tooth to the bone surrounding the tooth.

For dental caries to occur, a biofilm (also known as dental plaque) containing cariogenic bacteria (Mutans streptococci) adheres to the tooth surface. This biofilm organizes into a thick layer if it is not removed from teeth via regular toothbrushing with fluoridated toothpaste. Nourished by foods and beverages containing sugar, Mutans streptococci produce acid that initiates the tooth-demineralization process.