A cavity that forms on the surface between two teeth is known as an interproximal cavity, or an interdental lesion. This type of decay is common, yet it is often completely hidden from view during visual inspection. Because interproximal decay occurs in the tight space where adjacent teeth touch, it can advance significantly before a person experiences any obvious discomfort. Understanding the subtle signs of this hidden decay is important, but a professional dental examination is necessary for a definitive diagnosis. Early detection is crucial to preventing more extensive dental procedures.
Distinct Symptoms of Interproximal Decay
The presence of an interproximal cavity often reveals itself through sensory feedback rather than a visual change on the tooth’s surface. One of the first noticeable signs is a heightened sensitivity to thermal changes, particularly when consuming cold drinks or sweet foods. This reaction is caused by the decay penetrating the outer enamel layer, allowing external stimuli to reach the underlying dentin layer.
Another common indication is a localized, sharp twinge of pain that occurs specifically when biting down on food. Pressure applied during chewing can compress the decayed area, irritating the nerve tissue as the decay grows closer to the pulp chamber. The discomfort is usually a specific, repeatable pain point tied to the mechanical action of eating, rather than a constant toothache.
A change in the feel of the space between two teeth can also signal a problem. If dental floss consistently shreds, frays, or catches, it may indicate a surface irregularity caused by the decay process. Similarly, the persistent sensation of food getting trapped between the same two teeth suggests the cavity has begun to alter the natural contour of the tooth structure. These subtle sensations serve as important personal alerts that the integrity of the tooth surface has been compromised.
Why These Cavities Are Hard to Detect Yourself
Interproximal cavities are challenging for self-diagnosis due to the anatomical structure of the mouth. The tight contact point where two teeth meet acts as a shield, obscuring the area of decay from direct sight or mirror reflection. Unlike decay on chewing surfaces (occlusal cavities), which often presents as a visible pit or stain, interproximal lesions are hidden behind the adjacent tooth.
The way this decay progresses also contributes to its stealthy nature. Decay often begins in the enamel just below the contact point, where plaque accumulates and is difficult to remove with a toothbrush alone. The lesion then spreads inwardly through the dentin, the softer layer beneath the enamel, while the enamel surface remains relatively intact. By the time the decay becomes visible on the outer surface, the cavity is already advanced internally.
This progression contrasts with decay on exposed surfaces, which is easily spotted during a routine visual exam. A person cannot see past the curve of the tooth to the side wall hidden by its neighbor. Consequently, an individual often remains unaware of the lesion until it causes significant pain or until a dental professional uses specialized tools to uncover the damage.
Essential Professional Diagnostic Tools
Because of the difficulty in self-detection, dentists rely on specialized methods to diagnose interproximal decay. The primary tool for this purpose is the bitewing radiograph, commonly referred to as an X-ray. This specific X-ray provides a detailed view of the crowns of the back teeth, revealing the interproximal spaces.
Bitewing X-rays function because healthy tooth enamel and dentin absorb radiation and appear light gray or white on the film. Decayed areas have lost mineral content, allowing more radiation to pass through, which results in a distinct dark shadow on the X-ray image. The depth and spread of the lesion can be assessed by examining the shape and size of this radiolucent (dark) area between the teeth.
Beyond X-rays, the dental explorer checks for surface irregularities, though modern practice favors a blunt approach over aggressive probing. A curved instrument can be gently maneuvered into the proximal space to feel for textural change or softness that might indicate a developing lesion. Another non-radiographic technique is transillumination, which involves shining a focused light through the tooth. Decay appears as a dark shadow because the demineralized tissue does not transmit light as efficiently as the surrounding healthy enamel.
Treatment and Prevention Strategies
Once an interproximal cavity has been diagnosed, treatment depends on the extent of the damage. If the lesion is caught early and is confined to the outer half of the enamel, the process may be halted and potentially reversed through remineralization. This approach typically involves applying a high-concentration fluoride varnish or gel to strengthen the remaining tooth structure.
For decay that has progressed deeper into the dentin, a restorative procedure is necessary. This usually involves removing the decayed material and repairing the tooth with a dental filling, which restores the tooth’s function and contour. If the decay has reached the pulp, a root canal procedure may be required to save the tooth from extraction.
Preventing interproximal decay centers on oral hygiene focused on those tight spaces. Flossing once a day is the most effective preventative action, as toothbrush bristles cannot adequately clean the interdental surfaces. Using a flossing technique ensures the removal of the bacterial plaque film that initiates the decay process. Consistent use of a fluoride toothpaste also helps by making the enamel more resistant to acid erosion, forming a stronger barrier against future lesions.