Discolorations are classified as extrinsic or intrinsic. Extrinsic stains are located on the outer surface of the teeth, whereas, intrinsic stains are internal. The etiology and treatments are discussed below:

Extrinsic Discolorations

Stains on the outside of the teeth are quite common. In younger persons, stains may be related to remnants of Nasmyth's membrane, poor oral hygiene, existing restorations, bleeding gums, plaque accumulation, irregular eating habits or the presence of chromogenic bacteria or fungi. In older persons, stains on the teeth are more likely to be brown, black or gray and occur on areas adjacent to the gingival tissue. Poor oral hygiene is a contributing factor as well as coffee, tea and certain other types of foods.

Treatment

Most surface stains can be removed by routine prophylactic procedures. Some superficial discolorations on tooth colored restorations and decalcified areas on the teeth cannot be corrected by such cleaning. Conservative correction may be accomplished by surfacing the thin outer discolored layer with a flame shaped carbide finishing bur, followed by polishing with abrasive discs to obtain an acceptable result.

Intrinsic Discolorations

These are caused by deeper, internal stains and are more complicated to treat than external stains. Teeth with vital and nonvital pulps can be affected as well as root canal treated teeth. Vital teeth can be discolored at the time the crowns are forming and the abnormal condition usually involves several teeth. Factors include hereditary disorders, sickness, medications, excess fluorides and trauma. The staining may be located in the enamel or in dentin; discolorations restricted to dentin may still show through the enamel.

Treatment

Correction of intrinsic discolorations caused by lesions or failing restorations entails replacement of the faulty portion or the entire restoration. Many persons have definite esthetic problems from intrinsic stains, whereas other worry needlessly about the overall color of their teeth. People with light complexions may thing that their teeth are too dark when they are actually the normal color. Most stains can be treated and improved with methods such as bleaching or veneers. In fact, teeth whitening has become extremely popular for those who have no stains or discoloration. Just the desire to have whiter teeth has brought teeth whitening into the mainstream.