A dental crown is a tooth-shaped cap placed over a damaged tooth to restore its form, function, and strength. While mild sensitivity immediately following the procedure is common, pain that appears or persists six months later requires professional attention. This delayed discomfort is not normal settling pain and suggests a developing issue with the crown, the underlying tooth, or the surrounding tissue.
Pain Caused by Bite and Fit Problems
One frequent cause of delayed pain under a crown is occlusal interference, which is an issue with how the crown interacts with your bite. If the crown is slightly “high,” it receives excessive force every time you bite down or chew. This uneven pressure traumatizes the tooth and the ligaments holding it in the jawbone, leading to a dull ache or sharp pain when chewing.
Bruxism, or grinding and clenching your teeth, can significantly worsen a minor fit issue. Constant, excessive force on a crown that is not perfectly contoured irritates the underlying tooth structure and the periodontal ligament. This chronic trauma may cause the tooth to become tender to the touch or when biting. A simple adjustment by the dentist to shave down the high spot often provides immediate relief.
The overall shape of the crown, or its contour, can also contribute to problems if it is over-contoured or bulky. An improperly shaped crown traps food debris and makes cleaning difficult, leading to chronic inflammation of the surrounding gum tissue. The persistent inflammation causes localized pain and sensitivity often mistaken for a tooth problem.
Nerve and Pulp Issues Beneath the Crown
The most complex cause of delayed pain involves the biological response of the dental pulp, the tooth’s internal tissue containing nerves and blood vessels. Preparing the tooth for a crown involves drilling, which creates heat and vibration that can cause trauma. This initial trauma leads to inflammation, or pulpitis, which may take months to become symptomatic.
Initially, the inflammation may be reversible, allowing the pulp to heal if the source of irritation is removed. If the inflammation progresses, it becomes irreversible pulpitis, meaning the pulp tissue is permanently damaged. Symptoms include spontaneous, intense throbbing pain or lingering sensitivity to hot or cold temperatures. This pain may intensify when lying down or wake you up at night, indicating pressure building inside the tooth.
If the inflammation is left untreated, the pulp tissue can die, a process called necrosis. The dead tissue can become infected by bacteria, leading to a periapical abscess at the root tip. An abscess is a delayed issue that may take several months to form. Symptoms include pain when biting, swelling, or a persistent pimple-like bump on the gum. Teeth with deep decay or multiple restorations before the crown procedure are at a higher risk for this complication.
Secondary Decay and Structural Failure
New decay, termed secondary or recurrent caries, forms at the margin where the crown meets the natural tooth structure. If the seal between the crown and the tooth base is compromised, bacteria can seep underneath. This bacterial invasion, combined with poor oral hygiene, leads to a new cavity forming under the crown.
Pain from secondary decay is often sharp or sudden, particularly when consuming sweets or applying pressure, as the cavity deepens toward the nerve. Since the decay is hidden beneath the restoration, it can progress significantly before symptoms appear or before it is visible. This process weakens the remaining tooth structure, potentially leading to sudden structural failure.
The underlying tooth structure can also develop a hairline crack or fracture, often exacerbated by chewing or bruxism. A fracture allows fluid and bacteria to penetrate the sensitive inner layers of the tooth, causing sharp, intermittent pain that is difficult to pinpoint. Structural failure can also involve the crown material itself, such as a crack in the porcelain or metal, allowing external irritants to reach the tooth beneath.
Addressing the Discomfort Diagnosis and Treatment
Experiencing pain months after a crown placement signals the need for a prompt dental evaluation. The diagnostic process begins with a thorough clinical examination, focusing on the crown margins and surrounding gum tissue. The dentist will also check your bite using articulating paper to identify any premature or heavy contact points causing trauma.
Diagnostic imaging, such as a periapical X-ray, is essential to check for signs of secondary decay or infection at the root tip. The dentist will also perform vitality testing, applying a mild cold stimulus to assess the health and responsiveness of the dental nerve. The nature of the nerve’s response helps determine if the pulpitis is reversible or irreversible.
Treatment depends on the diagnosis, but common interventions are usually straightforward. If the issue is a high spot, a simple occlusal adjustment can immediately reduce the pressure. If secondary decay is found, the crown usually needs removal so the cavity can be cleaned and a new crown fabricated. If the nerve is diagnosed with irreversible damage, root canal therapy is required to save the tooth by removing the infected pulp tissue.