Professional teeth whitening is an in-office dental procedure designed to safely and effectively lighten the color of natural teeth by removing deep stains and discoloration. It uses high-concentration whitening agents—most commonly hydrogen peroxide or carbamide peroxide—that are significantly stronger than over-the-counter products. Because of this strength, the procedure is performed under the supervision of a dentist, with careful protection of the gums and soft tissues to ensure safety and comfort. The process typically begins with an examination and cleaning to confirm that the teeth and gums are healthy enough for whitening. The dentist records the starting tooth shade and discusses realistic expectations. During the procedure, a protective barrier or rubber shield is applied to the gums, and cheek retractors are used to keep the area dry. The whitening gel is then carefully applied to the front surfaces of the teeth. In some systems, a special blue LED light or laser is used to activate the gel and accelerate the breakdown of stains, although effective whitening can also occur without light activation. The whitening gel is usually left on the teeth for 15–20 minutes at a time and may be reapplied several times in a single visit, depending on the system used and the desired level of whitening. After the final application, the gel is removed and the teeth are rinsed. A fluoride or desensitizing treatment is often applied to reduce post-treatment sensitivity. The entire appointment typically lasts between 30 minutes and 2 hours, and many patients see their teeth become several shades lighter in just one session. Professional whitening delivers fast, noticeable results, but it is important to note that restorations such as fillings, crowns, and veneers do not change color. Dentists often provide guidance on maintaining results, including avoiding staining foods and drinks and, in some cases, using custom take-home trays for touch-ups. With proper care, results can last many months to over a year.