Dental bleaching, or teeth whitening, typically involves a procedure where a bleaching agent ,  usually containing hydrogen peroxide, is applied to the teeth to lighten their color. The process can be done in-office by a dentist or at home using dentist-provided materials. In-office treatments often involve using a protective gel on the gums, applying the bleaching agent, and sometimes activating it with a light or laser. 

Here's a more detailed look at the procedure:

In-Office Whitening:

1. 1. Preparation:

   The dentist will clean your teeth to remove any debris and assess your current tooth shade to track progress. 
2. 2. Gum Protection:

   A protective gel or rubber shield is applied to protect the gums from irritation. 
3. 3. Bleaching Agent Application:

   The whitening agent (containing hydrogen peroxide) is applied to the teeth. 
4. 4. Activation (Optional):

   A special light, laser, or heat source may be used to activate the bleaching agent, accelerating the process. 
5. 5. Agent Removal and Rinsing:

   After a set time (typically 30-60 minutes), the agent is removed, and the mouth is rinsed. 
6. 6. Follow-up:

   The dentist will evaluate the results and may recommend follow-up appointments or maintenance procedures. 

At-Home Whitening (using dentist-provided materials):

1. Custom Trays: The dentist will create custom-fitted trays that hold the whitening gel.
2. Gel Application: The patient applies the bleaching gel into the trays and wears them for a specified time each day.
3. Follow-up: Regular check-ups with the dentist are crucial to monitor progress and address any sensitivity issues.