Black's Classification of Caries Lesions

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• Class I: Caries affecting pits and fissures of molars and premolars,and Lingual of anterior teeth.
• Class II: Caries affecting proximal areas of posterior teeth of molars and premolars.
• Class III: Caries affecting inter-proximal areas of anterior teeth (central incisors, lateral incisors, canines).
• Class IV: Caries affecting the proximal areas of anterior teeth that also incorporate the tip/edge of (central incisors, lateral incisors, canines)
• Class V: Caries affecting cervical smooth surfaces of anterior or posterior teeth.

Diagnosis of erosion due to bulimia and other acid sources

Teeth are a mineralized structure made primarily from calcium. Because of this, they can be dissolved readily by acid. When this acid comes from bacteria, decay occurs. However there are other sources which can also provide enough acid to damage the teeth.
One common source of acid is the hydrochloric acid found in the stomach. Any time stomach contents are in the mouth, acid can cause erosion of the teeth. This becomes a potential problem for persons with bulimia, (habitual vomiting) gastric reflux esophogitis (GERD) or hernia (medical conditions which allow stomach contents to seep into the mouth when lying down).
Erosion of the teeth can easily be distinguished from wear of the teeth by clenching or bruxing. The following images describe characteristics of erosion.