It is our dream to have a set of healthy and white teeth, but usually the reality is unsatisfactory. Some people may have white teeth but they are unsightly, as the teeth are misaligned. In such case, orthodontic treatment is required. Some other people may have well-aligned teeth but they are discolored. How to fix a discolored tooth, and what are the causes of tooth discoloration? Let's take a look.

1. Causes of tooth discoloration

The color of tooth is primarily determined by the color of dentin and is modified by color of enamel. The translucent enamel is in creamy white color and has a fluorescent reaction, while the dentin is a yellowish brown color with low transparency. Thereby teeth look creamy white with a light yellow hue, because the dentin color is visible after penetrating through the enamel. The thinner the enamel, the more the dentin color is revealed.

Discolored tooth is referred to a natural tooth of which the color, hue or transparency have changed. Symptoms include the teeth turning gray, yellow, red and less transparent; opaque spots or strips, or yellowish brown spots with grooves on the surface; or one or more complex symptoms of enamel surface defects.

There are three main types of causes of tooth discoloration, exogenous, endogenous and tooth-related factors.

(1) Exogenous discoloration is caused by the build-up of colored residues on the surface of enamel, including plaque, material alba and food residues on the enamel surface and the neck of the tooth; pigment precipitation of colored foods, drugs, tobacco, etc.; ion deposition from drugs or metal minerals resulted from occupational exposure;

(2) Endogenous discoloration is a result of the absorption of pigment components by the tooth structure, including tooth hypoplasia or discoloration (fluorosis caused by high fluoride water); medication tooth discoloration (tetracycline teeth); pulp-related discoloration (pulpless tooth, the iron ions in the hemoglobin enter the dentin, deposit and integrate with the dentin after the pulp is decomposed during the absorption inside and outside the tooth, and the hydrogen sulfide produced by the necrotic pulp interacts with hemoglobin to form black iron sulfide), etc.;

(3) The tooth-related factors include tooth decay, discoloration of the fillings, enamel defects resulted from acid etching, dentin exposure caused by tooth wear.

2. Restoration plans for tooth discoloration

Mild tooth discoloration can be fixed by external tooth bleaching, surface grinding and polishing, and enamel remineralization; dental fluorosis and tooth with enamel hypoplasia, whether moderately or severely discolored, can be restored with all-ceramic veneers, as long as sufficient enamel is available. The moderate discoloration of tetracycline teeth and pulpless teeth can be fixed by bleaching the pulp chamber and wearing all-ceramic veneer; in case of severe discoloration, all-ceramic veneers cannot mask the discoloration completely, so full crown is recommended.

Discolored tooth can be aesthetically treated by the following procedures:

(1) Periodontal scaling and polishing. Exogenous stains can be removed by ultrasonic scaling and sandblasting;

(2) If there are tooth decay and old fillings with stained or discolored edges, the old fillings should be removed first, and then replaced by color-coordinated adhesive resin fillings;

(3) Grind and polish the enamel surface, and then remineralize the enamel. This method is effective for mild enamel hypoplasia, dental fluorosis, and other surface stains, brown or opaque spots on the enamel. At present, doctors mainly use a friction agent containing silica and hydrogen peroxide on the tooth surface, and then slowly remove the stains and polish the tooth surface. After that, enamel remineralization agent containing sodium fluoride will be applied to remineralize the enamel and restore the normal color of the tooth;

(4) Dental bleaching, including external bleaching and internal bleaching;

(5) Porcelain veneer. This is mainly used for moderate and severe dental fluorosis, moderate tetracycline teeth, pulpless teeth, etc.;

(6) Full crown restoration. In respect of moderately discolored tooth or extensive enamel defects, the doctor will restore and prepare the abutment tooth in accordance with the principles of conventional post-core-crown restoration and all-ceramic preparation, and restore the whole crown with all-ceramic materials to improvethe shape and color of the discolored tooth.

Please feel free to contact me if there’s any dental problem (WeChat ID: aiyuan325180).