A red or pink tooth usually signals one of two things: something external sitting on the enamel surface, or something internal happening beneath it. Surface stains from food and drink are harmless and easy to remove. But when the redness seems to come from inside the tooth itself, it typically means tissue is breaking down within the tooth or along its root, a process called resorption that needs professional attention.
Surface Stains That Look Red
The simplest explanation is an extrinsic stain, meaning pigment clinging to the outer enamel. Red wine is a common culprit because it combines deep plant pigments, acids, and tannins that help the color grip enamel. Beetroot, tomato-based sauces, berries like raspberries and blackberries, and brightly colored candy or drinks can all leave reddish deposits. These stains sit on the surface and don’t indicate damage. A good brushing, professional cleaning, or simply waiting a day usually takes care of them.
If you’ve recently eaten or drunk something deeply pigmented, that’s likely your answer. But if the redness persists after cleaning, or the color seems to glow from beneath the enamel rather than sitting on top of it, something else is going on.
The “Pink Tooth”: Internal Resorption
A tooth that turns pink or red from the inside is a classic sign of internal resorption. This happens when specialized cells called odontoclasts begin dissolving the hard tissue (dentin) from within the tooth. Normally, the soft inner layer of the tooth and its lining of protective cells act as a barrier, preventing this from happening. When that barrier is damaged, usually by trauma or chronic inflammation, these cells lose their protection and the dentin becomes vulnerable to breakdown.
As the dentin erodes from the inside, blood-rich granulation tissue grows into the space. This inflamed, highly vascular tissue is what gives the tooth its pink or red appearance. It shows through the thinning enamel, especially near the neck of the tooth where enamel is naturally thinnest. Dentists sometimes call this a “pink tooth of Mummery,” and it’s considered a hallmark of this condition.
Internal resorption is relatively rare. Estimates of its incidence range from 0.01% to 1% of all teeth, though the rate climbs significantly in teeth that have experienced trauma or certain dental procedures. In one study of 50 teeth with internal resorption, over half of the cases were linked to direct trauma or orthodontic treatment. Autotransplanted teeth (teeth surgically moved from one socket to another) carry an especially high risk: one study found internal resorption in 55% of transplanted canines over six years.
External Cervical Resorption
A closely related condition, external cervical resorption, eats into the tooth from the outside near the gumline rather than from within. It can also produce a visible pink spot in the lower third of the crown, where granulation tissue shows through thin enamel. This pink spot is considered a hallmark sign of the condition, though it doesn’t always appear.
External cervical resorption is tricky to catch because it often starts without any symptoms at all. Many cases are discovered accidentally during routine X-rays. In more advanced stages, you might notice sensitivity to temperature or pain when biting down. One way dentists distinguish it from a cavity is by probing the defect: resorption creates a hard, scratchy surface with sharp edges, while a cavity feels soft and sticky.
Color Changes After a Tooth Injury
If your tooth changed color after being hit, bumped, or knocked, the timeline of color change matters. Research tracking injured teeth with precise color measurements found that redness (measured as a shift in the red color spectrum) peaked around day 29 after trauma, then gradually decreased. Overall discoloration peaked around day 56, with the tooth appearing noticeably darker for weeks before slowly recovering.
A reddish tint in the first few weeks after trauma can indicate bleeding inside the pulp chamber, where blood products seep into the surrounding dentin. This doesn’t automatically mean the tooth is dying, but it does warrant monitoring. If the color shifts from pink or red to gray over time, that’s a stronger sign that the pulp has lost its blood supply and the tooth may no longer be alive.
How a Red Tooth Is Diagnosed
Your dentist will start with a visual exam and then test whether the tooth’s nerve is still functioning. The most common approach is a cold test, where a refrigerant spray or ice is applied to the tooth to see if you feel a normal sensation. Electric pulp testing, which sends a mild current through the tooth, is another option. Both of these measure nerve response. In some cases, dentists want to know about blood flow specifically, which can be assessed with laser Doppler flowmetry or pulse oximetry, though these tools are less commonly available in a general dental office.
Standard dental X-rays can reveal resorption, but they compress a three-dimensional structure into a flat image, which limits what they show about the size and location of the damage. A 3D cone-beam CT scan (CBCT) provides more detail. In one study, CBCT detected resorption with 88% sensitivity compared to lower rates for standard X-rays. CBCT was also better at identifying how far the damage had spread. The practical advantage is that 3D imaging can help distinguish internal from external resorption and pinpoint exactly where the breakdown is occurring, which directly affects what treatment makes sense.
Treatment and Outlook
For internal resorption, the standard treatment is root canal therapy. The goal is to remove the inflamed tissue inside the tooth and fill the space to stop the resorption from progressing. When caught before the tooth wall has been severely thinned, the prognosis is good. A large long-term study of root canal treatments found overall success rates of about 88% at the tooth level, with cumulative success holding at 93% at 10 years and 81% at 30 years. These figures reflect root canal outcomes broadly, not just resorption cases, but they give a reasonable picture of how durable the treatment can be.
External cervical resorption is treated differently depending on how far it has advanced. Smaller lesions can sometimes be accessed by lifting the gum tissue, removing the granulation tissue, and filling the defect. Larger lesions that have reached the pulp may also need root canal treatment. In severe cases where the tooth structure is too compromised, extraction becomes the more realistic option.
The key factor in both types of resorption is timing. These conditions are progressive, meaning the damage continues until something stops it. A tooth that looks slightly pink today can lose significant structure over months if left untreated. If the redness in your tooth isn’t explained by something you ate or drank, and especially if the color seems to come from within the tooth itself, getting it evaluated sooner gives you the best chance of keeping the tooth.