Updated: Sep 10, 2020
Tetracycline stains are both an intrinsic (occurs in the dentin or pulp layer) and endogenous stain (occurs during tooth development/calcification).
Tetracycline has been used for decades to treat bacterial infections of the skin (like acne), intestine, respiratory tract, urinary tract, genitalia, lymph nodes. It cannot treat viruses like the common cold, flu, or COVID-19.
This antibiotic binds to the calcium in teeth. About 90% of the enamel matrix is a hydroxyapatite matrix and calcium makes up 40% of it. When the tetracycline encounters light, it undergoes an oxidative reaction, leading to a color alteration in the tooth. So, if a pregnant woman takes tetracycline during the prenatal phase or a child utilizes it at any point during tooth mineralization or calcification, a staining pattern emerges in the adult and/or primary dentition.
The stain may involve florescent yellow, blue-grey, brown or black shades. The colours occur in stripes spanning horizontally across the tooth.
Did you know?
The location of the tetracycline stain typically correlates to when the individual was exposed to tetracycline and there are four degrees of severity for this staining pattern.
Tooth development is a methodical and staged process.
Teeth begin developing at roughly 6 weeks in utero. Teeth begin calcifying 4 months in utero and 2nd molars aren’t done calcifying until approximately 8 years of age. Calcification is the process of mineral deposition into the teeth. For this reason, the earlier you ingest tetracycline in this developmental process, the more pervasive the staining pattern.
Tetracycline staining incidence has reduced over time as the antibiotic is now contraindicated in pregnant patients. Doctors usually opt for other antibiotics during early childhood as well.
If you wish to eliminate the look of this stain, a composite or porcelain veneer are excellent options. Crowns, which are caps that go over the whole tooth, may work as well. New methods are also coming onto the market, such as vital bleaching with a KTP laser. Some methods of bleaching (ex: carbide peroxide bleaching) may be able to lighten the teeth, but cannot entirely eliminate the pattern.