Why Does My Tooth Still Hurt After a Filling?

Dr. Anand S

Co-Founder · MDS, Endodontics

You had a cavity filled, but the tooth still feels sensitive — to cold drinks, to biting, or even to air. This is one of the most common concerns patients raise after restorative treatment, and in most cases, it resolves on its own within a few weeks.

Why Sensitivity Occurs After a Filling

During cavity preparation, the tooth structure is removed close to the nerve (pulp). The deeper the cavity, the closer the preparation is to the nerve, and the more likely it is that the nerve will respond with temporary sensitivity.

• Sensitivity to cold: common in the first 1–2 weeks and usually resolves as the nerve settles.
• Sensitivity to biting: may indicate a slightly high filling that needs minor adjustment.
• Spontaneous or lingering pain: may suggest the nerve has been irreversibly affected.

The Role of Cavity Depth

A study published in the Journal of Dental Research found that the proximity of the restoration to the pulp is the strongest predictor of post-operative sensitivity. Cavities that extend more than 75% of the way toward the nerve carry a higher risk of persistent symptoms.

According to the American Dental Association, mild sensitivity after a filling is expected and typically resolves within 2–4 weeks. If the pain is sharp, worsening, or wakes you at night, it should be evaluated promptly.

When to Be Concerned

Most post-filling sensitivity is reversible — the nerve is irritated but recovers. However, in some cases, the decay may have been close enough to the nerve that irreversible damage has occurred. Signs that may indicate the need for further treatment include:

• Pain that lingers for more than 30 seconds after exposure to hot or cold.
• Spontaneous throbbing pain unrelated to eating or drinking.
• Swelling around the tooth or gum.
• Sensitivity that worsens rather than improves over time.

What You Can Do

Use a desensitising toothpaste containing potassium nitrate or stannous fluoride. Avoid extremely hot or cold foods for the first week. If the bite feels uneven, schedule a quick adjustment — this is a simple procedure that can make a significant difference.

If symptoms persist beyond 4–6 weeks or worsen, a clinical evaluation with thermal and electric pulp testing can help determine whether the nerve has recovered or whether root canal treatment may be needed.