Normal Tooth Shade and Factors Affecting Tooth Color
- Appearance of a tooth is influenced by factors such as lighting conditions, translucency, opacity, light scattering, gloss, and human perception.
- Intrinsic pigmentation, determined by genetic and natural factors, is the most influential in tooth color.
- Teeth have a thin, whiter, and semitransparent enamel layer on the outer surface.
- Underlying dentin layer is darker, yellow-brown in color, and less transparent.
- Dentin contributes most to the overall tooth color, while enamel contributes blue, pink, and green tints.
- Public opinion of normal tooth shade is often distorted due to media portrayals of cosmetically enhanced teeth.
- Tooth color varies according to race, gender, and geographic region.
- Females generally have slightly whiter teeth due to smaller tooth size and less visible dentin.
- Baby teeth are generally whiter than adult teeth due to differences in enamel to dentin ratio.
- Larger teeth, such as molars and canines, tend to be darker.

Causes of Extrinsic Tooth Discoloration
- Extrinsic discolorations can be caused by dental plaque stained by chromogenic bacteria.
- Neglected plaque can calcify and form calculus, which varies in color (grey, yellow, black, or brown).
- Tobacco products can cause a yellow-brown-black stain on teeth.
- Betel chewing and certain foods and drinks rich in carotenoids or xanthonoids can stain teeth.
- Certain topical medications and mouthwashes can cause extrinsic staining.
- Extrinsic discolorations can be caused by dental plaque, calculus, tobacco, betel chewing, certain foods and drinks, medications, and metallic compounds.
- Exposure to metallic compounds like iron, iodine, copper, nickel, and cadmium can cause staining.
- Ingesting colored liquids like sports drinks, cola, coffee, tea, and red wine can also discolor teeth.

Causes of Intrinsic Tooth Discoloration
- Intrinsic discoloration can occur during tooth development or later in life.
- Dental caries (tooth decay) can result in brown discoloration.
- Fluorosis, caused by chronic and excessive exposure to fluoride during tooth development, can lead to white flecks or severely hypoplastic patches on enamel.
- Trauma can cause red, grey, or yellow discoloration depending on the type of injury.
- Pulp necrosis, internal resorption, and root canal treatment can also cause intrinsic tooth discoloration.
- Root canal materials, such as gutta percha and root canal sealer cements, can cause discoloration.
- Lack of pulp pressure in dentinal tubules after pulp removal can lead to dietary stains in dentin.
- Amalgam fillings can darken the appearance of teeth.
- Tetracycline and its derivatives, like minocycline, can cause yellow-green or brown discoloration of dentin.
- Genetic disorders, such as enamel hypoplasia and dentinogenesis imperfecta, can affect tooth development and result in abnormal appearance.

Aging and Tooth Discoloration
- Intrinsic discoloration tends to accompany aging due to the deposition of darker secondary dentin.
- Tooth wear processes like attrition and acid erosion can thin the enamel layer and make it less porous.
- Aging can also lead to phosphate deficiency in enamel.
- Aging-related discoloration is a natural process and may or may not be of cosmetic concern.
- Management options for aging-related discoloration include tooth bleaching and dental restorations.

Management of Tooth Discoloration
- Discoloration of front teeth is a common reason for seeking dental care.
- Many individuals with teeth of normal shade still request teeth whitening.
- Management depends on the cause of discoloration and can involve cleaning, whitening toothpaste, scaling, polishing, and identification of the cause.
- Intrinsic discoloration often requires tooth bleaching or dental restorations.
- Cosmetic concern and underlying pathology should be considered in the management of tooth discoloration.