Local

• Intrapulpal hemorrhage

• Pulp necrosis

• Root resorption

• Chemicals (irrigants, sealers, etc.)

• Aging

• Tetracycline staining

• Genetic (amelogenesis imperfecta, dentinogenesis imperfecta)

• Fluorosis

• Dystrophic calcification

• Congenital erythropoietic porphyria

• Congenital bilirubinemia

• Wine, coffee, tea, bacterial, chocolate, tobacco, mouthwashes

• Metallic stains (copper, iron, silver)