Stains can be categorized as internal and external.
- Internal stains are caused by dental decay, a non-vital tooth or a previous Root canal treatment (RCT), fluorosis, or tetracycline staining – Generally cannot be whitened. The stains are permanent, but various treatment options are available to whiten the teeth.
- External stains can be caused by colored food, beverages such as coffee, red wine, and from smoking. These stains can be prevented by good oral hygiene practices, rinsing after taking a colored drink, or routine scaling and polishing. The underlying color of the tooth can brighten with teeth whitening. These stains are not permanent.