A single tooth appearing darker than its neighbors can be a source of concern. This common dental issue stems from various underlying causes. Understanding why a tooth changes color is the first step toward addressing the problem. Fortunately, a darkened tooth is often treatable, and dental professionals can restore its natural appearance and health.
Common Reasons for a Single Dark Tooth
Physical trauma is a frequent cause for a tooth to darken, even from a minor injury. An impact can damage the tooth’s internal pulp, which contains nerves and blood vessels. This damage leads to internal bleeding, similar to a bruise, where blood products stain the surrounding tooth structure, causing it to appear gray, brown, or black. Discoloration can manifest years after the initial injury.
Dental decay, or cavities, also contributes to tooth darkening. As bacteria erode enamel and progress into the dentin, the tooth can turn brown or black. This discoloration is often visible on the surface, indicating the extent of the decay. Untreated decay can reach the pulp, leading to infection and further darkening.
Previous dental work can also be a factor. Old amalgam (silver) fillings contain metals that can leach into the tooth structure, causing grayish or black discoloration. Teeth that have undergone root canal treatment may also darken because the pulp and its blood supply are removed, and residual blood products or the absence of living tissue can lead to a duller shade.
Internal resorption is another reason. This condition involves the body’s cells breaking down the tooth’s internal structure, often starting in the pulp chamber. It can lead to pinkish or dark discoloration, sometimes called “pink tooth of Mummery,” as the internal tissue is reabsorbed.
When to Seek Professional Advice
Any new or sudden discoloration of a single tooth warrants professional evaluation. While some causes might be benign, a change in tooth color can signal an underlying dental issue. A dentist can determine the cause and appropriate course of action.
Look for accompanying symptoms. These might include pain or sensitivity in the affected tooth, especially when biting or chewing, or a persistent dull ache. Swelling around the gum line, a bad taste, or a loose tooth associated with the discoloration also indicate professional help is needed.
Inform your dentist if there is a history of trauma to the tooth, even if the injury occurred years ago and no immediate discoloration was noted. Trauma can lead to nerve death and discoloration long after the incident. Beyond health concerns, cosmetic appearance is a valid reason to seek dental advice. If the darker tooth affects your confidence, a dentist can discuss aesthetic options.
How Dentists Diagnose Discoloration
Dentists use a systematic approach to diagnose a discolored tooth, beginning with a thorough clinical examination. During this visual inspection, the dentist assesses the tooth for decay, fractures, existing fillings, and other visible abnormalities. They also compare the discolored tooth to its neighbors to note the extent and nature of the color change.
Pulp vitality testing is an important step to determine the health of the tooth’s nerve. This involves applying stimuli, such as a cold test or an electric pulp test, to gauge the tooth’s response. A normal response indicates a healthy nerve, while an exaggerated, lingering, or absent response can point to inflammation or nerve death. This helps differentiate between a living tooth with external staining and a non-vital tooth with internal discoloration.
X-rays, or radiographs, provide an essential internal view of the tooth and surrounding bone not visible during a clinical exam. These images can reveal issues like deep decay, root canal problems, bone loss, or internal resorption, common causes of intrinsic discoloration. A detailed patient history, including past dental trauma, previous procedures, and medical conditions, helps the dentist make an accurate diagnosis.
Treatment Approaches
Once the cause of the dark tooth is diagnosed, several treatment options are available. For internally darkened teeth, often following a root canal, internal whitening is a specialized technique. This procedure involves placing a bleaching agent inside the tooth, where it works from within to lighten the discoloration. The agent is sealed inside the tooth for a period, and multiple applications may be required to achieve the desired shade.
External whitening, or professional teeth bleaching, primarily targets surface stains. While effective for overall tooth brightening, its impact on deeply discolored, non-vital teeth is limited. It may be considered for superficial discoloration or if the tooth’s internal health is good, but it is generally not the primary solution for intrinsic darkening.
Restorative options like veneers or crowns are effective for severe discoloration or when the tooth is structurally compromised. Veneers are thin, custom-made shells, typically porcelain, bonded to the tooth’s front surface, concealing discoloration and improving appearance. Dental crowns, which cover the entire tooth, offer a comprehensive solution for severely discolored, fractured, or weakened teeth. A dentist can use an opaque layer within the crown to mask the dark tooth.
If the tooth’s pulp is non-vital or infected, root canal treatment is often necessary to save the tooth. This procedure removes damaged or infected pulp, cleans and disinfects the tooth’s inside, then fills and seals the space. After a root canal, internal whitening or a crown may still be recommended for remaining discoloration. When decay causes darkening, removing the decayed portion and placing a filling or crown is the primary treatment to restore health and appearance.