In which procedure is the use of topical anesthetic commonly applied?

Topical anesthetic is commonly applied before administering local anesthesia because it serves to numb the area where the injection will take place. By applying a topical anesthetic, patients experience reduced discomfort during the initial needle penetration, making the process more comfortable. This practice is especially important in dental settings, where anxiety about needles and injections can be significant for patients.

The other procedures listed may involve other forms of anesthesia or discomfort management, but they do not typically require the application of topical anesthetic prior to their initiation. For instance, while dental crowns require careful adjustment and placement, they do not generally involve needles that necessitate prior topical numbing. Similarly, while teeth whitening procedures may cause sensitivity, they do not typically involve the administration of local anesthesia, and topical anesthetics aren't commonly used. After root canal treatments, local anesthesia has already been administered and the need for additional topical anesthetic is minimized since the area is already numb.