What characterizes a Class II caries lesion?

A Class II caries lesion is characterized as a cavity found on the proximal surfaces of posterior teeth, often affecting molars and premolars. In this stage, the lesion typically extends beyond the enamel and into the dentin, often progressing more than halfway through the enamel. This kind of progression indicates that the caries has breached the outermost protective layer of the enamel and is moving into deeper structures, which is essential for the classification of the lesion.

Options like involving the dentin-enamel junction or not extending through the DEJ would suggest a different classification of caries. Similarly, extending through the pulp would classify a more advanced stage of dental decay, typically recognized as a Class IV or extensive caries that require different management. Thus, identifying that Class II lesions extend more than halfway through the thickness of the enamel is crucial for accurate diagnosis and treatment planning in dental hygiene practice.