It happens all of the time that I receive questions regarding teeth whitening. Is it effective? Is it safe? What’s the difference between at home and in office whitening? Will it whiten my crown or fillings? I figured I would devote a blog post to explaining how teeth whitening (bleaching) works and answer common misnomers.
How does teeth whitening work?
Firstly it’s important to understand the two types of stain that occur in teeth. Extrinsic stain is stain that gathers on the outer surface of teeth. This type of stain can be polished off by our wonderful hygienists. Intrinsic stain is stain that accumulates deep inside of the tooth and cannot be removed by cleaning the outside of the tooth.
Stain is made up of color molecules that are attracted to each other through magnetic bonds. These bonds within the molecule can be thought of as magnets, and just like with magnets some are easier to pull apart than others. This is one factor that makes some whitening cases easy, and some more stubborn. These color molecules tend to join together and attract other color molecules. This leads to larger and larger molecules that appear darker and darker.
Whitening gels contain hydrogen peroxide which breaks down into water (H2O) and oxygen (O2), but also can create free radicals. You’ve probably heard of these molecules as harmful substances that can cause breakdown of cells within the body. In teeth whitening however, we use these to our advantage to break down color molecules that cause staining. The goal of whitening is to get rid of these molecules that absorb light, causing more light to be reflected to our eyes and thus making teeth appear whiter.
Is it safe?
Yes! Teeth whitening with hydrogen peroxide is very safe as long as manufacturer recommendations are followed. Although teeth whitening may make teeth sensitive, this is only for a short period of time and it will not cause any irreversible damage to the tooth or the nerve of the tooth.
What’s the difference between in office and at home whitening?
For in office bleaching we use a much higher concentration of hydrogen peroxide gel that could be harmful to soft tissue if protocols are not followed. To avoid damaging patients’ gums and lips we place a plastic protect layer over the lips and an extrudable material over the gums to prevent chemical burn. We also use an ultraviolet light that is shined on the teeth during the process to accelerate the reaction. This allows us to achieve fantastic whitening results in a one hour time period.
Will it whiten my existing crowns and fillings?
No, existing crowns and fillings on front teeth will remain the color they are before whitening. If you have an existing filling or crown that matches your current shade of teeth, the crown or filling will appear darker after whitening. We recommend a consult with your dentist to decide on a cosmetic plan before any whitening procedure is performed.
As you can see, teeth whitening with peroxide is a very safe and effective procedure that can greatly increase confidence in your smile.