Carious Lesions Occur in Four General Areas of the Tooth

Pit and Fissure Caries (Figure 2) - includes class I occlusal surfaces of posterior teeth, lingual pits of maxillary incisors, and buccal surfaces of mandibular molars.
Smooth Surface Caries & Interproximal Surface Caries (Figure 3) - includes class V buccal, lingual surfaces of anterior and posterior teeth, and class II interproximal surfaces of all teeth below the interproximal contact points.
Root Surface Caries (Figure 4) - cementum is exposed due to teeth traumatized by conditions such as malocclusion, consistent bruxing, or clenching. Due to cementum being only 50% mineralized, root surface caries can occur if the patient receives multiple lactic-acid exposures.
Secondary or Recurrent Caries (Figure 5) - Includes caries seen adjacent to or beneath an existing restoration.

Figure 2. Pit and Fissure Caries.

Figure 3. Smooth Surface Caries & Interproximal Surface Caries.

Figure 4. Root Surface Caries.

Figure 5. Secondary or Recurrent Caries.

Image source: The Ohio State University College of Dentistry

Current Concepts in Preventive Dentistry Carious Lesions Occur in Four General Areas of the Tooth