Short answer: Inflammation under a crown usually develops when decay caused by bacteria leaking in at the crown margin reaches the tooth's nerve, or when nerve tissue that was already damaged gradually loses its vitality. You may notice pain when chewing, throbbing, swelling of the gum or discharge. Diagnosis is made through examination, vitality tests and X-rays; treatment is root canal therapy through the crown, crown replacement or, if necessary, extraction.
Many people assume that once a tooth has been crowned, it will never cause problems again. In reality, there is still living or root-canal-treated tooth tissue under the crown, and that tissue can also decay and become inflamed. Inflammation under a crown is one of the main causes of pain, swelling and sensitivity in a crowned tooth. In this article we explain why inflammation develops under a crown, the symptoms of a painful crowned tooth, how the diagnosis is made and the treatment options such as root canal therapy or crown replacement.
Why does inflammation develop under a crown?
Inflammation under a crown usually develops when decay under the crown, caused by bacteria leaking in at the crown margin, reaches the tooth's nerve, or when nerve tissue that was already damaged before the crown was placed gradually loses its vitality.
- Marginal leakage and decay under the crown: The margin where the crown meets the tooth is a sensitive area in terms of oral hygiene. Gradual dissolution of the luting cement, loss of marginal fit or gum recession exposing the root surface can allow bacteria to seep under the crown. Decay that starts here can progress unseen because the crown hides it.
- Pre-existing deep decay or a large filling: Teeth that receive crowns have often already lost a lot of structure. The nerve tissue may have been stressed during this process and can become inflamed months or years after the crown is placed.
- Effects of crown preparation: Shaping a living tooth for a crown places a certain load on the nerve tissue. Most teeth tolerate this without problems; in some teeth, however, the nerve may lose its vitality over time.
- Cracks and fractures: Cracks in the tooth or root under the crown can give bacteria a pathway.
- Inadequate or old root canal treatment: In root-canal-treated teeth, canals that were not fully cleaned or leakage from the restoration above can cause inflammation to return at the root tip.
- Gum and bone problems: A crown margin placed too deep under the gum or margins that are hard to clean can contribute to gum inflammation and bone loss.
- Excessive bite load: A crown that sits high in the bite, or teeth clenching, can lead to inflammation and sensitivity in the tooth's supporting tissues.
Symptoms
Symptoms of inflammation under a crown include pain that increases when chewing or when the tooth is touched, throbbing pain triggered by heat or starting on its own, swelling or discharge from the gum and a bad taste in the mouth. In some cases there are no symptoms at all, and the problem is noticed on a routine X-ray.
- Pain when biting on the crowned tooth, or the tooth feeling "high"
- Lingering pain triggered by hot drinks
- Spontaneous throbbing that gets worse at night
- Redness, swelling or bleeding of the gum around the crown
- A small pimple-like bump with discharge on the gum at root level
- Dark discoloration at the crown margin or a grayish look at the gum line
- Bad odor or taste
- A loose or dislodged crown
- Swelling in the cheek or jaw
Teeth that have lost their vitality may not be sensitive to hot or cold; so the thought "my tooth isn't sensitive to cold, so there's no problem" can be misleading.
Diagnosis
Inflammation in a crowned tooth is diagnosed by evaluating the clinical examination, tooth vitality tests and X-ray findings together; because the crown covers the visible surface of the tooth, this assessment requires care.
- Clinical examination: The fit of the crown margins, the condition of the gum and the tooth's response to percussion (gentle tapping) and biting are checked. Gum pocket depths may be measured.
- Vitality tests: A cold test or similar methods are used to assess whether the tooth's nerve is alive. The crown material can make some tests harder to perform.
- X-rays: Periapical X-rays can show inflamed areas at the root tip, decay at the crown margin and the condition of previous root canal treatment. Crowns containing metal can partly obscure the image.
- CT scan: When a root crack is suspected, the root anatomy is complex or a detailed evaluation is needed before root canal retreatment, a cone beam CT may be requested.
Sometimes the source of the pain is not the crowned tooth itself but a neighboring tooth or a non-dental structure such as the sinus. An accurate diagnosis prevents unnecessary procedures.
Treatment: root canal therapy or replacement
Depending on the source of the problem, treatment of inflammation under a crown is planned as one of the following: root canal treatment through the crown, removing the crown and replacing it after treating the decay underneath, retreating an existing root canal, or extraction for teeth that cannot be saved.
Root canal treatment through the crown
If the crown fits well, there is no decay at its margins and the tooth has lost its vitality, root canal treatment can be carried out through a small access opening in the chewing surface of the crown. After treatment, the opening is sealed with a filling. With this method, the dentist evaluates the soundness of the crown and the durability of the access area.
Removing and replacing the crown
If there is a marginal misfit, decay under the crown or a fracture, the crown is removed. The decay is cleaned, root canal treatment is done if needed, the tooth is reinforced and a new crown is prepared. A temporary crown protects the tooth during this process.
Root canal retreatment and surgical options
If inflammation persists in a tooth that has had root canal treatment before, the old filling material is removed and the canals are cleaned and filled again. In suitable cases, apical resection (apicoectomy), in which the root tip is surgically cleaned, may be considered.
Extraction
If there is a vertical root fracture, extensive loss of tooth structure or significant loss of supporting tissue, the tooth may not be salvageable. In that case it is extracted, and the gap can be restored with an implant, a bridge or a denture.
If there is acute swelling and pain, the dentist may prioritize emergency measures such as draining the infection. Antibiotics are used only when the dentist considers them necessary, and together with treatment aimed at the source.
Prevention
The key to reducing the risk of inflammation under a crown is cleaning the crown margins well every day and catching possible leakage or decay early through regular check-ups.
- Carefully clean the crown margins with a brush angled toward the gum line.
- Clean the sides of the crown every day with floss or an interdental brush; under bridges, clean beneath the pontic with floss that has a spongy section.
- Use fluoride toothpaste; if your decay risk is high, your dentist may recommend additional fluoride applications.
- Limit how often you have sugary foods and drinks.
- If you clench or grind your teeth, discuss a night guard with your dentist.
- If you notice a loose crown, a catching feeling at the margin or changes in your gum, do not put off a check-up.
- Have a check-up at least once or twice a year, with X-ray evaluation when needed.
For other topics you may be curious about, take a look at our frequently asked questions page.
Examination for a painful crowned tooth in Ankara
If you feel pain when chewing, swelling of the gum or a bad taste around a crowned tooth, identifying the source of the problem improves the chances of saving the tooth. At our polyclinic in Park Oran Ofis on Kudüs Caddesi in Çankaya, after an examination and X-ray evaluation, root canal treatment, crown replacement or other options are explained to you. To book an appointment, you can use our contact page.
Frequently asked questions
Why does a crowned tooth hurt?
Causes of pain in a crowned tooth include decay under the crown, inflammation of the tooth's nerve, infection at the root tip, a root crack, gum inflammation and a crown that sits high in the bite. An examination and X-rays are needed to identify the cause.
Can root canal treatment be done without removing the crown?
If the crown fits well and there is no decay at its margins, root canal treatment can be done through a small access opening in the chewing surface. If there is marginal leakage or decay under the crown, the crown needs to be removed and replaced.
How can you tell if there is decay under a crown?
Decay under a crown is often not visible from the outside. Dark discoloration at the crown margin, a catching feeling, bad odor or sensitivity can be clues; a definitive assessment is made with an examination and X-rays.
Does inflammation in a crowned tooth go away on its own?
No. Even if the pain eases from time to time, the problem usually persists and can flare up again as long as the source of the inflammation is not treated. Early treatment improves the chances of saving the tooth.
