An interproximal cavity is a form of tooth decay that develops on the surfaces between two adjacent teeth, typically just below the point where they touch. This area is difficult to clean, making it highly susceptible to plaque accumulation. These cavities are insidious because they often progress silently, remaining hidden from view until the decay has advanced significantly into the tooth structure. By the time a person experiences noticeable symptoms, the decay may be substantial, potentially requiring more extensive treatment than a simple filling.
The Subtle Symptoms of Interproximal Decay
While these cavities are often called “silent,” they can produce subtle warning signs. One of the earliest indicators is a heightened sensitivity to temperature extremes or sweet foods and drinks. This sensation might feel like a sharp feeling that seems to originate from between two specific teeth.
Another clue is found during flossing, where the thread might repeatedly shred, break, or catch in the exact same spot, indicating a rough edge or early decay. Persistent, localized bad breath or a foul taste, despite regular brushing, may be caused by food debris and bacteria trapped within the cavity space. A dull ache or mild discomfort when biting down or chewing can also signal that decay is reaching the inner layers of the tooth.
Why Interproximal Cavities Are Hard to See
Interproximal cavities form on the side of the tooth, beginning just beneath the enamel contact point where one tooth presses against the next. This tight space is obscured by the adjacent tooth and is often partially covered by the gum tissue.
Looking in a mirror or using a small light will not reveal the decay because the outer layer of enamel remains intact for a long time, hiding the internal damage. By the time an interproximal cavity creates a visible dark spot or a noticeable hole, the decay is extensive and has penetrated through the enamel and into the underlying dentin. This hidden location explains why professional diagnostic tools are necessary for early detection.
Professional Detection: The Role of X-Rays
Interproximal cavities require diagnostic imaging for early detection. The bitewing X-ray is the primary method for diagnosing this type of decay. This specific technique captures a detailed image of the crowns of the upper and lower back teeth, clearly showing the spaces between them.
On the radiograph, healthy enamel and dentin appear white or light gray because they block the X-rays. Decayed areas have lost mineral content, making them less dense, so the X-rays pass through easily, causing the cavity to appear as a dark shadow or a distinct notch on the side of the tooth. Regular bitewing X-rays allow a dentist to detect decay when it is still confined to the outer enamel, which may allow for less invasive treatment. The frequency of these X-rays is determined by a patient’s individual risk factors for decay, ranging from every six months for high-risk patients to every 12 to 24 months for low-risk adults.
Next Steps After Diagnosis
Once an interproximal cavity is confirmed by the X-ray, intervention is necessary to prevent the decay from progressing. If the decay is caught early and only involves the outer half of the enamel, the dentist may recommend non-surgical treatment, such as fluoride application, to encourage the tooth to remineralize. This approach can reverse the process before a filling is needed.
For decay that has passed the enamel-dentin junction, a dental filling is the most common restorative treatment. Ignoring the diagnosis allows the decay to spread rapidly toward the tooth’s pulp, which contains the nerves and blood vessels. Decay reaching the pulp will require a more complex procedure, such as a root canal or even the extraction of the tooth, making early detection and treatment beneficial for preserving the natural tooth.