Clinical review required: Tooth discoloration may be external, internal, developmental, traumatic, medication-related or caused by decay and pulp disease. A single dark tooth requires diagnosis before whitening.

What are discolored teeth?

Discoloration means a change in tooth colour, brightness or translucency. It may affect one tooth, a group or the entire dentition. Some colour variation is natural and healthy. Treatment depends on where the pigment lies and why it developed; polishing cannot remove deep intrinsic colour, while bleaching cannot lighten ceramic crowns.

Extrinsic stain

External stain accumulates on enamel or plaque from tobacco, coffee, tea, wine, chromogenic foods, iron products or some rinses. Professional cleaning and improved plaque control can reduce it. A whitening toothpaste may remove some surface stain through abrasives, but aggressive use can wear exposed roots or roughen restorations.

Intrinsic discoloration

Internal colour lies within enamel or dentine. Causes include ageing, trauma, pulp death, developmental enamel or dentine conditions, fluorosis, tetracycline exposure and previous dental materials. Peroxide bleaching may improve some intrinsic stains, but response and uniformity vary.

A single dark tooth

One tooth can darken after trauma, pulp necrosis, root-canal treatment, internal resorption, decay or restorative leakage. Pulp tests and radiographs may be needed even when there is no pain. Whitening a necrotic tooth from the outside without treating infection can delay essential care.

White, brown and grey changes

Chalky white areas can reflect early caries, fluorosis, developmental hypomineralisation or dehydration. Brown spots may be stain, arrested caries or enamel defects. Grey colour can arise from trauma, restorative materials or dentine change. Colour alone does not determine whether a lesion is active.

Assessment

The dentist records onset, distribution, trauma, medicines, diet, smoking, symptoms and previous treatment. Examination evaluates plaque, enamel texture, decay, restorations, pulp and gum health. Photographs and shade records support planning. Transillumination or radiographs are used when structural or pulpal disease is suspected.

Professional cleaning

Scaling, air polishing and polishing remove different deposits and stains. The least abrasive effective method should be selected for enamel, exposed dentine, composite, ceramic and implants. Cleaning reveals the underlying tooth shade and should often precede decisions about bleaching or restoration.

Whitening toothpastes

These mainly remove external stain; they do not substantially change deep tooth colour like peroxide. Abrasiveness varies. Charcoal and unregulated powders may scratch surfaces or increase wear. Patients with recession, erosion or sensitive teeth need product-specific advice.

Home tray whitening

Custom trays use prescribed carbamide or hydrogen peroxide for controlled periods. They allow gradual shade change and touch-ups. Too much gel or prolonged wear increases sensitivity and gum irritation without guaranteeing a whiter result. Existing crowns, veneers and fillings retain their shade.

In-office whitening

Higher-concentration peroxide is applied with soft-tissue protection. It can produce rapid change, though immediate brightness partly reflects dehydration and can rebound. Light activation is not automatically necessary for durable whitening. Sensitivity and gum irritation remain possible.

Internal bleaching

A root-treated dark tooth may be whitened from inside after the quality of the root filling and coronal seal are assessed. A protective barrier is placed over the root filling before bleaching agent. Risks include colour relapse and rare cervical root resorption, so diagnosis, isolation and follow-up are essential.

Microabrasion and resin infiltration

Enamel microabrasion removes a very shallow surface layer to reduce selected superficial white or brown defects. Resin infiltration can blend some non-cavitated white lesions by changing optical properties. Lesion depth and activity determine suitability; neither method treats active deep decay.

Composite bonding

Composite can mask local colour and reshape enamel conservatively. Opaque and translucent layers are balanced to avoid a flat appearance. Composite can stain and may require polishing or repair. Deep discolouration can show through unless enough masking space exists.

Veneers

Porcelain or composite veneers can mask resistant intrinsic colour and modify shape. Dark substrates require careful material thickness and opacity, which may increase preparation. Whitening and conservative options should be considered first. Veneers do not treat pulp disease or active decay.

Crowns

A crown is appropriate when a tooth also needs major structural coverage, not simply because colour is difficult. It requires circumferential preparation and creates a long-term replacement cycle. Very dark cores, metal posts and gum position influence the final shade and translucency.

Medication and developmental stains

Tetracycline-related banding and developmental defects can be resistant and may require staged bleaching, infiltration, bonding or veneers. Fluorosis ranges from subtle white mottling to surface breakdown. Treatment should match severity and preserve enamel rather than automatically covering every affected tooth.

Colour matching restorations

If whitening is planned, it generally precedes final composite, veneer or crown shade selection. Teeth need time to rehydrate and stabilise. Laboratory communication includes photographs, shade maps and substrate colour. Exact matching under every light source is not always possible.

Preventing new stain

Maintain plaque control, moderate tobacco and frequent chromogenic exposure and attend professional cleaning when needed. Rinsing with water after staining drinks is reasonable. Extreme “white diets” are not essential. Smoking cessation benefits oral and general health far beyond colour.

When to seek prompt care

A newly darkened single tooth, especially after trauma, needs assessment. Pain, swelling, a gum pimple, fracture or colour change in a child requires timely care. Rapidly spreading swelling, fever or breathing and swallowing difficulty is urgent.

Treatment abroad

Ask whether discoloration is extrinsic or intrinsic, whether pulp health was tested and how restoration shades will be coordinated after bleaching. Unregulated high-strength products can burn tissue. Obtain material, concentration and internal-bleaching barrier records.

Questions to ask

Where is the colour located?
Is the pulp healthy?
Will cleaning or bleaching change it?
Which existing restorations will not whiten?
Can infiltration or bonding preserve more tissue?
When will the final shade stabilise?

Frequently asked questions

Why is one tooth grey?

Trauma, pulp death, root-canal materials or restorations are possible; examination is required.

Will whitening change crowns?

No. Ceramic and composite retain their existing shade.

Are whitening toothpastes bleaching?

They mainly polish external stain and have limited effect on intrinsic colour.

Can white spots be whitened?

Whole-tooth whitening may alter contrast, but lesion-specific infiltration, microabrasion or remineralisation may be more appropriate.

Sources and clinical review references

Editorial review note: Evidence reviewed 22 July 2026. Named clinician review is required before indexation.

Discolored Teeth