A dark spot on a tooth can be alarming. It is a common misconception that any black or dark brown discoloration automatically signals active tooth decay. In reality, the color of a tooth’s surface can change for several reasons, and not all dark spots represent a structural problem that needs immediate restorative treatment. Understanding the distinction between a harmless stain and a true cavity is important.
Non-Caries Causes of Dark Spots
Many dark spots that appear on teeth are the result of external factors, known as extrinsic staining, which adhere to the outer enamel surface. Common sources include pigmented foods and beverages, such as coffee, tea, red wine, and dark berries, all of which contain chromogens that can lead to discoloration. Tobacco use, whether smoking or chewing, is another strong contributor to surface staining that can range from brown to black. These types of stains are superficial and do not compromise the integrity of the tooth structure.
Another common cause of dark discoloration is dental calculus, also called tartar, which is plaque that has hardened or mineralized over time. Calculus absorbs stains easily and can appear yellow, brown, or even greenish-black, especially below the gumline. While calculus itself is not decay, its rough texture promotes further plaque accumulation, making its professional removal necessary for gum health.
Arrested decay is a former cavity that has stopped progressing. This occurs when the conditions that caused the decay, such as poor hygiene or high sugar intake, are reversed, often with the help of fluoride. The dark spot left behind is highly mineralized scar tissue that feels hard and smooth to the touch, requiring monitoring rather than a dental filling.
Characteristics of Active Tooth Decay
Active decay indicates a breakdown of the tooth structure caused by acid-producing bacteria. It has physical characteristics that differentiate it from benign stains or arrested lesions. A key feature a dentist looks for is a soft or sticky texture when the area is lightly probed, suggesting the underlying dentin is demineralizing and losing its hardness. This decay often begins in deep pits and fissures on the chewing surfaces or in difficult-to-clean areas between teeth.
Active decay may also present with noticeable symptoms. Sensitivity is a common complaint, manifesting as discomfort when consuming hot, cold, or sweet foods and drinks. Pain when chewing or a spontaneous toothache can signal that the decay has advanced significantly, potentially irritating the dental pulp. Early-stage lesions may appear as a white or light brown spot on the enamel before darkening to black as they progress.
Professional Diagnosis and Management
Diagnosing the nature of a dark spot requires a thorough examination by a dental professional. The process begins with a visual inspection, followed by a tactile examination where the dentist uses an explorer tool to assess the spot’s hardness and texture. Active decay will feel soft, while an arrested lesion or a stain will feel hard and smooth.
A primary diagnostic tool is the use of dental X-rays, or radiographs, which allow the dentist to see beneath the enamel surface and check for internal progression of decay. Since decayed tooth material is less dense than healthy structure, it appears as a darker area on the X-ray film, confirming whether a surface spot has penetrated the underlying dentin.
Management is tailored to the diagnosis. Extrinsic stains and calculus are removed with a professional cleaning and polishing, while arrested decay is managed with simple monitoring, often called watchful waiting. Active decay requires restorative treatment, such as a dental filling or, in advanced cases, a crown, to halt the progression and restore the tooth’s function.