Have you ever looked in the mirror and noticed one tooth that seems darker than the others? Not just a little stained from coffee, but noticeably grey or brown. It can feel unsettling, especially if there is no pain. Many people assume it is simply surface staining, but in some cases a colour change can be a signal that something deeper is happening inside the tooth.
Tooth discolouration is common. Yellowing with age, brown staining from food and drink, or mild enamel changes are part of everyday dentistry. However, when a single tooth turns grey, dark brown, or even bluish, it may indicate internal tooth damage rather than simple extrinsic staining. Understanding the difference between external and intrinsic changes can help you know when to seek professional assessment.
What Actually Determines the Colour of a Tooth?
The colour of a tooth is influenced by several layers and structures:
- Enamel, the outer protective layer
- Dentine, the layer beneath enamel that has a natural yellow tone
- The dental pulp chamber, which contains nerves and blood vessels
- The blood supply to the tooth
- Age related enamel thinning
Extrinsic tooth staining affects the enamel surface. This includes yellow or brown staining from diet, smoking, or certain beverages. These changes often affect multiple teeth and are usually cosmetic.
Intrinsic tooth discolouration, on the other hand, occurs within the structure of the tooth. It may involve dentine, pulp tissue, or internal bleeding. This type of change often affects a single tooth and may signal internal damage.
When Does Tooth Discolouration Suggest Internal Tooth Damage?
Internal discolouration often appears as:
- A tooth turning grey
- A dark brown tooth enamel change
- A bluish tone after trauma
- A single discoloured tooth among otherwise normal teeth
Common causes include:
- Trauma to front teeth
- Dental pulp inflammation
- Pulp necrosis
- Internal bleeding tooth following injury
- Periapical infection
- Internal resorption
- Pulp calcification
Trauma does not always mean a dramatic accident. Even a minor knock during sport or a fall in childhood can disrupt the nerve and blood vessels in teeth. Sometimes the colour change is immediate. In other cases there is delayed colour change after injury, appearing months or even years later.
What Happens Inside a Tooth After Trauma?
When a tooth experiences trauma, the blood supply to the pulp can be compromised. This may lead to inflammation, reduced vitality, or complete loss of vitality.
The internal pathway often progresses in stages:
| Stage | What Happens Inside the Tooth | Possible External Sign |
| Initial Trauma | Blood vessel disruption | Slight colour change |
| Pulp Inflammation | Increased pressure within pulp chamber | Sensitivity to pressure |
| Pulp Necrosis | Loss of vitality | Grey or darkening tooth |
| Periapical Infection | Infection at root tip | Swelling or tenderness |
Not every discoloured tooth becomes infected. Some non vital teeth remain symptom free for extended periods. However, a grey tooth after injury should be assessed to rule out pulp necrosis or early infection.
How Is Internal Discolouration Different From Surface Staining?
Understanding enamel vs dentine staining can clarify the distinction.
| Feature | External Staining | Internal Discolouration |
| Cause | Food, drink, smoking | Trauma, infection, pulp damage |
| Number of Teeth | Often multiple | Usually one |
| Colour | Yellow or brown surface staining | Grey, dark brown, bluish |
| Pain | Typically none | May or may not be present |
| Treatment Approach | Professional cleaning or cosmetic management | Clinical diagnosis required |
| Urgency | Usually cosmetic | May require timely assessment |
Surface stains generally respond to professional cleaning or whitening under clinical guidance. Internal damage, however, requires a different approach. Whitening may not be suitable if the discolouration is linked to pulp damage.
What Symptoms May Accompany a Discoloured Tooth?
Some people experience no pain at all. Others notice subtle changes such as:
- Sensitivity to pressure
- A dull ache
- Swelling around the tooth
- Tenderness when biting
- Gum abscess signs
- Cracked tooth symptoms
Tooth infection signs can include swelling, persistent throbbing, or discomfort that comes and goes. In some cases there are no symptoms until an infection becomes more advanced.
It is important to remember that colour change does not always indicate infection. Some teeth remain stable and require monitoring only. Individual findings vary depending on cause and timing.
How Do Dentists Assess Tooth Vitality?
When a patient presents with a discoloured tooth nerve damage concern, assessment usually includes:
- Clinical examination
- Tooth vitality testing
- Percussion testing
- Dental radiographs
- Evaluation of the pulp chamber
Vitality testing helps determine whether the pulp is still responsive. Radiographs can show signs of periapical infection or internal resorption. These tools allow for a conservative treatment plan where appropriate.
What Are the Management Options for a Non Vital Tooth?
Management depends on the diagnosis.
Possible pathways include:
- Monitoring and review if the tooth remains stable
- Endodontic therapy if pulp necrosis is present
- Internal bleaching for certain cases
- Full coverage restoration if structural compromise exists
- Restorative management of cracked tooth symptoms
Not all cases require root canal treatment. Early assessment may help determine appropriate management before complications develop.
Why Should a Dark Tooth Never Be Ignored?
A single brown tooth enamel change can be more than a cosmetic issue. Infection at the root tip can affect surrounding bone. Internal damage that is left untreated may progress silently.
Delayed colour change after injury is particularly important in children and teenagers. Trauma to front teeth during sport is common, and even if the tooth feels fine, ongoing monitoring may be required.
Australian clinical guidance highlights that dental trauma should be followed up carefully due to the risk of later pulp necrosis and periapical infection.
Where Can You Seek Professional Assessment in Artarmon?
If you notice a tooth turning grey, developing a dark patch, or changing colour following trauma, professional evaluation is essential. At Artarmon Dentists, the focus is on careful diagnosis, conservative management where possible, and clear explanations so you understand what is happening inside your tooth.
The team uses clinical examination, vitality testing, and radiographic assessment to determine whether discolouration is superficial or linked to internal tooth damage. Where treatment is required, options are discussed in detail so you can make an informed decision about your oral health. Every case is approached individually because tooth vitality, infection risk, and structural integrity vary from person to person.
Early assessment can help prevent progression of pulp necrosis or periapical infection and allow timely restorative management where needed.
References:
Australian Dental Association
Dental Trauma Management Guidelines
https://www.ada.org.au
Dental Board of Australia
Guidelines for advertising a regulated health service
https://www.dentalboard.gov.au/Codes-Guidelines/Guidelines-for-advertising-a-regulated-health-service.aspx
Australian Society of Endodontology
Information on pulp necrosis and endodontic assessment
https://www.endodontics.org.au
FAQs About Tooth Discolouration and Internal Damage
Can a tooth turn grey without pain?
Yes. A non vital tooth may show no symptoms initially. Colour change can occur even when there is no discomfort.
How long after trauma can a tooth change colour?
Delayed colour change after injury can occur weeks, months, or even years later depending on pulp response and blood supply disruption.
Does every dark tooth need root canal treatment?
No. Some discoloured teeth remain stable and may only require monitoring. Treatment depends on vitality testing and radiographic findings.
Is whitening suitable for internally discoloured teeth?
Whitening may not address intrinsic discolouration caused by pulp necrosis. Clinical assessment is required to determine suitability.
Can children’s teeth change colour after injury?
Yes. Trauma to front teeth in children is common and can affect pulp vitality. Ongoing review is often recommended.
What are the early signs of internal tooth infection?
Possible signs include sensitivity to pressure, mild swelling, or a grey or darkening tooth. Some infections develop without significant pain initially.
Disclaimer
All dental procedures involve potential risks and benefits. The information provided in this blog is general in nature and should not be taken as medical advice. We recommend that you seek guidance from a suitably qualified health professional before making decisions about your oral health. Where appropriate, you may also wish to consider obtaining a second opinion.
Any images or videos featured are shared with the informed consent of our patients and are intended for educational purposes only. They are not a guarantee of results, as every patient is unique. Treatment outcomes — including recovery, potential complications, and effectiveness — can vary from person to person.