1. Intrinsic causes In a tooth with an intact blood and nerve supply, the causes are:

Hereditary disorders.

Tetracycline medication.

Excessive fluoride intake in drinking water.

High fevers associated with early childhood disease.

The loss of blood supply and nerve supply can by itself cause discoloration of the tooth.

2. Extrinsic causes Stains from tobacco smoking. Bacteria producing colored pigments.

A salivary protein layer covering the tooth surface.

The tinted remnants of a certain membrane seen on the teeth surface as the teeth, initially erupt out into the mouth.

Tooth decay or a broken down filling.