A cavity can look like a white, brown, or black spot on a tooth, depending on how far the decay has progressed. In more advanced cases, it may look like a visible hole or an area where part of the tooth surface has broken down.
Early tooth decay may appear as a whitish or yellowish area that looks dull rather than shiny. As decay progresses, the surface can become rough and may develop brown or darker coloring. If the decay reaches the dentin beneath the enamel, the affected area may look brown and feel softer or more fragile.
Not every dark spot is an active cavity. Some areas of stopped or inactive decay can also appear brown or dark but may be smooth, shiny, and hard. Because color alone cannot confirm a cavity, dentists also consider the tooth's texture, location, and whether there is actual loss of tooth structure.
A dental examination is the best way to determine whether a suspicious spot is a cavity. Regular dental care and good plaque control can help identify and manage decay before a larger hole develops.