Which of the following is a common indication for using calcium hydroxide in dentistry?

Calcium hydroxide is frequently used in dentistry as a cavity liner primarily due to its protective and therapeutic properties. When placed in a cavity preparation, it serves to protect the pulp tissue from thermal and chemical irritation caused by restorative materials. This is particularly important in cases where the dentin is exposed and there is a risk of pulpitis or pulp damage.

Additionally, calcium hydroxide has antimicrobial properties, which helps to reduce the risk of secondary infections in the area being treated. It also promotes the formation of secondary dentin, which can contribute to the natural defense mechanisms of the tooth. This makes its application as a cavity liner a crucial step in ensuring the long-term health of the tooth structure following restorative procedures.

The other options presented have specific functions in dentistry but do not accurately represent the primary use of calcium hydroxide. Binding to tooth structure is not a characteristic function of calcium hydroxide, and while it is used in some whitening processes, it is more relevant in the context of treating cavities and not specifically for cosmetic purposes. Its application for orthodontic purposes does not align with its common uses, as calcium hydroxide is not typically associated with orthodontic treatments.