Many people believe a dental crown provides complete immunity from tooth decay. However, while the crown itself cannot decay, the natural tooth structure beneath it remains susceptible to cavities. This article will explain how and why decay can form under a dental crown and what individuals can do to protect their oral health.
Understanding Dental Crowns
A dental crown is a custom-made cap that covers a damaged or weakened tooth. It restores the tooth’s shape, size, strength, and appearance. Crowns are made from various materials, including porcelain, ceramic, metal alloys, or a combination like porcelain-fused-to-metal. To place a crown, a dentist prepares the natural tooth by removing a small amount of its outer structure. The crown is then cemented over the prepared tooth.
Cavities and Your Crown
The artificial material of a dental crown is impervious to decay; therefore, a cavity cannot form directly on it. Instead, cavities develop on the natural tooth structure underneath the crown. This often occurs at the margin, the seam where the crown meets the tooth and gum line. If the interface between the crown and tooth is compromised or exposed, it creates an opportunity for decay.
Why Cavities Form Under Crowns
Cavities often form under crowns due to improper oral hygiene. Inadequate brushing and flossing around the crown’s margin allows plaque, a sticky film of bacteria, to accumulate. These bacteria produce acids that erode tooth enamel, leading to decay. An ill-fitting crown is another common reason, as it can create microscopic gaps where bacteria and food particles seep underneath, becoming difficult to clean.
Gum recession can also expose the softer root surface of the tooth beneath the crown, making it highly vulnerable to decay. If any decay was not entirely removed before the crown was placed, it could continue to progress. A diet high in sugars and acidic foods contributes to an oral environment where decay-causing bacteria thrive, increasing the risk around crowned teeth.
Finding and Preventing Cavities
Detecting Cavities
Detecting a cavity under a crown can be challenging as it is often hidden. Dentists identify these cavities during routine check-ups through visual examination and dental X-rays, which can reveal decay. Symptoms can include sensitivity to hot or cold temperatures, persistent pain, or discoloration around the crown. Swelling or bleeding gums around the crowned tooth may also indicate an issue.
Preventing Cavities
Prevention involves diligent oral hygiene, such as brushing twice daily with fluoride toothpaste and flossing daily, paying close attention to the crown margin. Regular dental check-ups and professional cleanings allow dentists to monitor the crown’s integrity and detect early signs of decay. Limiting sugary and acidic foods and beverages in the diet reduces the risk of decay.
Addressing Cavities Under Crowns
If a cavity is discovered under a crown, the treatment approach depends on the extent of the decay. For small, accessible cavities, a dentist might treat them with a simple filling without removing the crown. More commonly, if the decay is moderate to large, the existing crown needs removal to thoroughly clean out the decay. After treatment, a new crown is placed.
If decay reaches the pulp, a root canal procedure may be necessary before a new crown is placed. For severe decay that has severely compromised the tooth, extraction may be the only option. Prompt treatment is important to prevent further damage.