Dark spots on teeth are a common cosmetic and health concern, ranging from simple surface stains to signs of deeper structural issues. Discoloration may appear as tiny dots, streaks, or blotches, varying in color from brown to black. Only a dental professional can conduct a thorough examination to determine the underlying cause. Understanding how these spots form is the first step toward addressing the issue and protecting oral health.
Dark Spots Caused by Surface Staining
The most frequent origin of dark spots is extrinsic staining, where pigments adhere to the outer layer of the tooth enamel. This discoloration is primarily caused by consuming intensely colored foods and beverages. Common culprits include coffee, tea, red wine, and dark sodas, which contain chromogens that embed themselves into the enamel surface.
Tobacco use is also a significant contributor, often leading to distinct brown or black deposits. Poor oral hygiene allows plaque to harden into tartar (calculus), which appears as yellow, brown, or black, typically near the gumline. Additionally, certain chromogenic bacteria produce pigments that react with iron in the saliva, resulting in black lines or dots near the gums. These surface-level discolorations are often the easiest to remove through professional cleaning.
Structural Damage and Internal Reasons for Discoloration
Dark spots that originate within the tooth structure, known as intrinsic discoloration, often signal a change to the dentin, the layer beneath the enamel, or a pathological condition. The most concerning cause is dental caries, or decay, where bacteria produce acids that erode the enamel and penetrate the tooth. As decay progresses, the affected area darkens, creating a visible brown or black spot that requires restorative treatment.
The presence of older dental restorations can also manifest as dark spots or a gray hue in the tooth. Amalgam (silver) fillings contain metallic components that can corrode over time and stain the surrounding dentin, making the tooth appear darker from the inside. Similarly, if the seal around a filling or crown begins to leak, bacteria and staining agents can seep into the tooth’s margins, causing a dark border to form.
A tooth that has experienced trauma may darken due to internal damage to the pulp tissue. The injury causes internal bleeding, and the resulting blood degradation products infiltrate the dentin tubules, giving the tooth a gray or dark appearance. Developmental issues can also cause intrinsic discoloration, such as fluorosis from excessive fluoride intake during tooth formation, which manifests as white streaks or brown spots. Additionally, certain medications, notably tetracycline antibiotics, can permanently incorporate into the developing dentin, causing a distinct dark yellow, gray, or blue discoloration.
Professional Diagnosis and Treatment Options
A dentist is the only professional who can accurately distinguish between a harmless surface stain and a deeper structural problem like decay or internal damage. The diagnostic process typically involves a visual examination, gentle probing of the spot to check for softness indicative of active decay, and dental X-rays to assess the internal health of the tooth structure and look for hidden decay or pulpal issues. This comprehensive approach allows the clinician to determine the precise origin of the discoloration.
Treatment is tailored to the diagnosed cause of the dark spot. For extrinsic stains and tartar buildup, professional dental cleaning and scaling effectively remove the deposits. Teeth whitening procedures are often used for generalized surface staining or certain types of intrinsic discoloration. If the dark spot is confirmed to be decay, restorative treatments such as a filling, onlay, or crown are necessary to remove the damaged tissue and seal the tooth. For internal discoloration from trauma or failed restorations, procedures like internal bleaching or placement of veneers may be recommended.