When will a patient begin to feel sensation when a tooth is subject to a carious attack?

A patient typically begins to feel sensation when the carious attack progresses to the amelodentinal junction, which is the area where the enamel meets the dentin. As caries develop, they first disrupt the outer enamel, which is usually not sensitive due to its hard structure and lack of nerve endings. However, once the decay reaches the dentin beneath the enamel, this layer is much more sensitive because it contains microscopic tubules filled with fluid and connected to nerve endings.

At the amelodentinal junction, the dentin is affected, leading to sensations of pain or discomfort. This is the point where the tooth structure is compromised enough that the patient might experience sharp sensations or sensitivity, especially to temperature changes or sweet substances. Thus, the correct choice highlights the critical transition from a non-sensitive to a sensitive state in dental caries progression. The other choices reflect stages of decay that do not typically cause sensation, as enamel is not innervated, and exposure of the pulp represents a later, more severe stage of dental decay.