Due to the microscopic spaces in the structure of the teeth, cigarettes, tea, coffee and other foods cause yellowing and staining on the teeth. In bleaching systems using hydrogen peroxide and carbamide peroxide, it dissolves inorganic substances in teeth that have undergone color change for various reasons. The treatment is applied between 1 and 4 weeks. Its permanence varies between 7 and 10 years. Zirconium-coated or full-ceramic materials, which are state-of-the-art products, are used in the processes.