A child’s tooth turning grey, dark blue, or purple can be an alarming sight for a parent, but this form of discoloration is a common occurrence, usually signaling an internal reaction to a previous injury, such as a fall or a bump to the mouth. This trauma may have happened days or weeks earlier. The discoloration indicates damage beneath the tooth’s surface within the pulp tissue, which requires a professional assessment to determine the tooth’s health status.
Why Teeth Turn Grey: The Underlying Causes
A tooth turns grey due to a traumatic injury that damages blood vessels within the pulp chamber. The pulp is the soft tissue inside the tooth containing nerves and blood vessels. When trauma occurs, these vessels rupture, causing internal bleeding (hemorrhage) within the tooth’s core, similar to a bruise.
The grey tint is caused by the breakdown of blood products, specifically hemoglobin, which seeps into the dentin tubules. This process can take a few days to a few weeks to become noticeable. If the injury is minor, the tooth may be “bruised,” and the color could lighten over time as the blood products are reabsorbed.
In severe cases, the injury disrupts the blood supply, leading to pulp necrosis (death of the nerve tissue). When the pulp dies, the tooth is no longer vital, and the dark color often persists permanently. Necrosis carries the risk of developing an infection or abscess at the root.
Implications for Primary Versus Permanent Teeth
The prognosis for a discolored tooth varies significantly depending on whether it is a primary (baby) tooth or a permanent one. Primary teeth have a remarkable capacity to heal and may sometimes revascularize, restoring the blood supply. The discoloration may fade over several months as the tooth heals. If the primary tooth remains discolored but shows no signs of infection, monitoring may be sufficient until the tooth naturally exfoliates.
A grey permanent tooth is a more serious concern, often indicating that the pulp has died and will not recover. This requires immediate intervention to save the tooth, as necrotic pulp can lead to severe infection. An injury to a primary tooth can also affect the developing permanent tooth bud beneath it, causing future developmental defects. Prompt treatment is necessary to prevent tooth loss and protect the underlying bone structure.
Diagnosis and Professional Assessment
Any child with a discolored tooth requires a professional dental evaluation, even without pain, because the damage is internal. The dentist begins with a visual examination, checking the tooth for mobility and assessing the surrounding gum tissue for swelling or a “gum pimple,” which signals an abscess. The assessment also includes checking for tenderness by gently tapping the tooth (percussion testing).
A dental X-ray is necessary to assess the internal structures of the tooth and surrounding bone. The X-ray allows the dentist to check the root for signs of internal or external resorption (breakdown of the root structure). For primary teeth, the X-ray determines if the injury has impacted the developing permanent tooth bud. Pulp vitality tests may also be used to confirm if the nerve tissue is still alive.
Treatment Options for Discolored Teeth
Following a comprehensive diagnosis, the treatment plan for a grey tooth depends on the tooth type, the extent of damage, and the presence of infection. Treatment generally falls into three main categories: monitoring, pulp therapy/root canal, or extraction.
Monitoring
The most common approach for a grey primary tooth without infection is monitoring over time. If the tooth is stable and asymptomatic, the dentist recommends regular follow-up appointments and X-rays. This ensures the color remains stable until the tooth naturally falls out.
Pulp Therapy or Root Canal
If the tooth is infected, or if the grey color is accompanied by an abscess or pain, more active intervention is required. For a primary tooth, pulp therapy (pulpotomy or pulpectomy) may be performed to maintain the tooth’s space until the permanent tooth is ready to erupt. A necrotic permanent tooth nearly always requires a full root canal to remove the dead tissue and prevent further infection.
Extraction
Extraction is reserved for teeth that are severely infected, cannot be saved by therapy, or pose a threat to the underlying permanent tooth. For a primary tooth, extraction may be the safest choice if the infection is extensive. After the infection is resolved, cosmetic options like composite bonding or a crown can improve the appearance of a permanent tooth that remains discolored.