Class II cavities occur in which part of the teeth?

Class II cavities specifically refer to dental caries that occur on the mesial (toward the midline of the dental arch) or distal (away from the midline) surfaces of posterior teeth, which primarily includes molars and premolars. These cavities are classified under the "Class II" designation in the Black classification system for dental caries, which categorizes carious lesions based on their location within the tooth structure.

The reason Class II cavities are associated with the mesial and distal surfaces of posterior teeth is due to the anatomy of these teeth. They have multiple surfaces, and the structure of posterior teeth, including their grooves and proximal surfaces, makes them more susceptible to decay in those areas. Unlike anterior teeth, which are more visible and generally experience different types of caries development, the posterior teeth's anatomy lends itself to Class II cavities occurring particularly in the interproximal (between the teeth) areas where plaque can accumulate.

Understanding the classifications of cavities is crucial in dental assisting and treatment planning, as it informs how a dental professional will assess, treat, and restore a tooth affected by decay.