It’s a bleaching process for colored teeth to restore the normal healthy color of enamel dentin.
Some habits affect your teeth color: types of drinks and food cause teeth colorings like tea, coffee, and cola. Salsa soup or syrup and some colored fruits. Smoking as well causes coloring teeth.
Actually, any material can color your teeth, because it has opened pores that get affected by any colors.
Though that, some cases of teeth whitening can’t be done:

• For those who are less than 16 years, some teeth whitening solutions can affect roots and cause sensitivity.
• Sensitive teeth, as it could increase sensitivity.
• Brown, lead, and purple-colored teeth are hard to bleach by usual ways but another cure can be used to get them bleached.

Laser bleaching: lots of people are worried about laser bleaching due to hydrogen peroxide that increases teeth sensitivity, but with technological progress in dentistry and laser bleaching; now it’s safe.
Check up after bleaching: it’s important to visit the dentist for a bleaching examination after one week of the process done.
Your doctor will advise you to reduce your consumption of food and drinks which cause dark spots and colored teeth, you can always get them bleached for a period that’s ranged between 6 months to a year.