Tooth Sensitivity: Common Triggers and When to Seek an Evaluation

What is actually happening in a sensitive tooth

Beneath enamel and below the gum line lies dentin, a layer filled with thousands of microscopic tubules that lead toward the nerve inside the tooth. When dentin is exposed, temperature changes, sugary or acidic foods, and even air can move fluid within those tubules. The nerve registers that movement as a short, sharp pain. Dentists call this dentin hypersensitivity.

The defining feature of ordinary sensitivity is that the pain is brief and stops soon after the trigger is removed. Pain that lingers, throbs, or appears without any trigger points to a different problem and is discussed below.

Common reasons dentin becomes exposed

Sensitivity is rarely random. It usually reflects one or more processes that remove the protective covering over dentin.

• Gum recession, which exposes root surfaces that have no enamel covering
• Enamel erosion from frequent acidic drinks such as soda, sports drinks, citrus, and wine, or from acid reflux
• Abrasion from brushing too hard or using a hard-bristled brush
• Wear from clenching or grinding, often at night
• Recent whitening, which commonly causes temporary sensitivity
• Recent dental work such as a new filling or a deep cleaning, which may be sensitive for a short period

When sensitivity may signal something else

Several conditions can feel like sensitivity at first. A cavity, a cracked tooth, a leaking or broken filling, or inflammation of the nerve can all produce pain with cold or sweets. The difference is often in the details: where the pain is, how long it lasts, and whether it is getting worse.

Seek an evaluation from a licensed dentist if you notice any of the following:

• Pain that lingers for more than several seconds after the trigger is gone
• Sensitivity confined to one tooth rather than a general area
• Sharp pain when biting down or releasing a bite, which can suggest a crack
• Spontaneous or throbbing pain, or pain that wakes you at night
• Swelling, a pimple-like bump on the gum, or a bad taste
• Sensitivity that has not improved after a few weeks of using a desensitizing toothpaste

Everyday steps that often help

For straightforward dentin hypersensitivity, home measures are often effective, though improvement can take a few weeks of consistent use.

• Use a desensitizing toothpaste containing potassium nitrate or stannous fluoride twice daily, and consider smoothing a small amount over sensitive areas before bed without rinsing
• Switch to a soft-bristled brush and use gentle, short strokes rather than scrubbing
• Limit how often you sip acidic drinks, and rinse with water afterward
• Wait before brushing after acidic foods or reflux episodes, since softened enamel is more easily worn
• Ask about a night guard if you suspect grinding

What a dentist may evaluate or offer

An evaluation usually involves identifying which teeth respond, checking for decay, cracks, or failing restorations, and looking at gum levels and wear patterns. X-rays may be used to rule out deeper problems.

If the cause is exposed dentin, in-office options can include fluoride varnish, bonding agents that seal the tubules, or tooth-colored bonding over notched areas at the gum line. Where recession is significant, a referral to discuss gum grafting may be considered. When the cause is a cavity, crack, or nerve problem, treatment is directed at that cause rather than the symptom.

Sources and further reading

American Dental Association, MouthHealthy: "Sensitive Teeth" (mouthhealthy.org).

Cleveland Clinic: "Sensitive Teeth" health library article (clevelandclinic.org).

Canadian Advisory Board on Dentin Hypersensitivity, "Consensus-based recommendations for the diagnosis and management of dentin hypersensitivity," Journal of the Canadian Dental Association, 2003.