– Dental caries are not evenly distributed throughout the mouth.
– Certain surfaces of the teeth are particularly susceptible to carious lesions; others are nearly immune.
– In the late 1800s, Dr. G.V. Black classified the most common sites for dental caries.
– His classification system adequately describes most simple carious lesions.
– In high-caries patients, a single tooth may have more than one lesion.
– These lesions may be of the same class or of different classes.
– The pits and fissures of teeth, particularly posterior teeth, are the most susceptible to dental caries.
– Pit and fissure caries are called Class I lesions, and the associated restorations are called Class I restorations.
– The area of the tooth just below the interproximal contact is also susceptible to caries.
– If such a lesion occurs in a posterior tooth, it is called a Class II lesion.
– Dental radiographs are commonly used to diagnose Class II caries.
– If interproximal caries occur in an anterior tooth, it is called a Class III lesion.
– Dental radiographs and clinical examination are commonly used to diagnose Class III lesions.
– If a Class III lesion is left untreated, it may progress and involve the incisal angle
of an anterior tooth.
– A lesion that involves the incisal angle of an anterior tooth is called a Class IV lesion.
– Class IV restorations are also used to restore the incisal angle of an anterior tooth that has been fractured as the result of trauma.
– The gingival third of the facial and lingual surfaces of both anterior and posterior teeth
is susceptible to caries when patients have poor oral hygiene or a high-sugar diet.
– The Class VI lesion was a later addition to Black’s classification.
– A Class VI lesion involves the cusp tip or incisal edge of a tooth.
– Actually, a Class VI carious lesion is quite rare.
– For most people retaining a large number of teeth later in life, however, wear of cusp tips and incisal edges is not uncommon.
– When attrition causes dentin to become exposed, it wears much faster than the surrounding enamel because enamel is much harder than dentin.
– The result is a “dished out” area of worn dentin.