Tooth discolouration refers to a change in the natural colour of teeth. It can be localised to one tooth or affect multiple teeth. It may be purely cosmetic, or in some cases, a sign of underlying developmental or dental disease.
Understanding the cause is essential because it determines whether treatment is simple (like cleaning or whitening) or requires restorative or endodontic care.
1. Developmental (Intrinsic) Discolouration
These changes occur during tooth formation and are incorporated into the tooth structure before eruption.
Systemic or Generalised Causes
- Fluorosis – excess fluoride during enamel formation causes white, chalky streaks to brown mottling in severe cases
- Tetracycline staining – antibiotic exposure during tooth development, causing grey, brown, or banded discolouration
- Amelogenesis imperfecta – a genetic enamel formation defect leading to thin, rough, pitted, or discoloured enamel
- Dentinogenesis imperfecta – a genetic dentine disorder producing blue-grey, opalescent teeth with increased wear risk
Localised Developmental Causes
- Turner tooth – a single-tooth enamel defect caused by trauma or infection of a primary tooth affecting the developing permanent tooth
- Developmental hypoplasia or hypomineralisation (enamel that forms thin, weak, or chalky)
2. Acquired (Environmental) Discolouration (After Eruption)
These occur after teeth erupt and are broadly divided into external surface stains and internal tooth changes.
External (Surface) Staining
These affect the enamel surface and are often reversible:
- Coffee and tea
- Smoking/vaping
- Chromogenic bacteria (pigment-producing bacteria, common in children and some adults)
- Chlorhexidine mouthwash (brown staining with prolonged use)
- Poor oral hygiene and plaque accumulation
- Certain foods and dietary pigments
These stains often respond well to professional cleaning, polishing, or whitening.
Internal (Intrinsic) Acquired Discolouration
These originate within the tooth structure:
- Pulp necrosis (non-vital tooth) – grey, dark brown, or black discolouration due to breakdown of blood products inside the tooth
- Trauma – bleeding within the pulp or nerve damage leading to gradual darkening
- Internal resorption – “pink tooth” appearance due to internal tooth structure breakdown
- Root canal-treated teeth – may darken over time, depending on materials and sealing
- Age-related changes – natural darkening due to enamel thinning and dentine thickening
Key Clinical Point
Discolouration is not always cosmetic. Important red flags include:
- A single tooth changing colour
- History of trauma
- Associated pain or sensitivity
- Gradual darkening of a previously normal tooth
These may indicate pulp damage or necrosis.
When to Seek Assessment
You should have discolouration assessed if:
- It appears suddenly
- Only one tooth is affected
- It follows trauma
- It is associated with pain, swelling, or sensitivity
- It is progressively worsening
Management
Treatment depends entirely on the cause:
- Surface stains: hygiene care, scale and polish, airflow cleaning, whitening
- Intrinsic mild staining: professional bleaching systems
- Structural or severe discolouration: veneers, composite bonding, or crowns
- Pulp necrosis or trauma-related darkening: root canal treatment followed by internal/external bleaching or restoration
- Developmental conditions (AI, DI): protective restorations and long-term management planning
Final Message
Tooth discolouration can range from harmless staining to a sign of underlying developmental defects or nerve damage. Correct diagnosis is critical before any cosmetic treatment is started.
If you are concerned about changes in tooth colour, the team at Dural Dental Practice can identify the cause and provide appropriate treatment options to restore both appearance and long-term tooth health.
