Single dark (root-canal-treated) tooth

Intracoronal bleaching is used for discolouration in a non-vital tooth. External whitening is unlikely to remove an intrinsic stain that lies within dentin, so treating the tooth internally addresses a different location from surface whitening.

A veneer changes what is seen at the front of the tooth. A porcelain veneer is a thin custom-made shell; a composite veneer is tooth-coloured filling material bonded to the tooth. Both routes begin by matching a shade to the surrounding teeth.

Within veneer choices, porcelain tends to cost more than composite. Porcelain is custom-made in a dental laboratory after an impression or 3D scan, while composite may need fewer appointments and less enamel removal.

Porcelain veneers are strong and long-lasting. Composite veneers are easier to repair after damage, but they do not resist staining or wear as well. A veneer can chip, crack, wear down, or loosen over time, which can mean re-bonding, repair, or replacement.

External cervical resorption has been reported rarely after internal bleaching of non-vital teeth. Veneer placement removes a small amount of enamel from the front and sides, and placing a veneer over an unhealthy tooth can leave the underlying problem untreated.

Existing restorations generally do not change colour with whitening, and metallic or other restorative materials can affect the colour seen in a tooth. That makes the colour and position of each restoration part of the decision before either approach is chosen.

Start by locating the discolouration: internal bleaching is for a non-vital tooth, whereas a veneer covers the facial surface. Then weigh enamel removal, the presence of restorations that will not whiten, and whether porcelain or composite better fits the desired repair and wear trade-off.