Causes of tooth discoloration.

- Food & Beverages / Age / Medicines (tetracycline, fluoride) / White-spot lesions / Trauma / Root canal treatment / Dental restorations

The color and appearance (extent/size, location, surface texture, etc...) of tooth staining can usually give you a pretty good idea of what has caused it.

Types of tooth discolorations and their causes -

  • Chromogenic agents (foods / beverages / other consumables) -

    The dark compounds that make up the products we consume (coffee, tea, cola, wine, tobacco, etc...) can cause generalized yellow, brown or burnt orange-colored tooth stains.
    [Details]

  • Age-related -

    As years pass, it's normal for a person's teeth to take on a generalized yellow or brown coloration, with associated tooth dinginess and darkening.
    [Details]

  • Genetic factors -

    The baseline color of a person's teeth may naturally be more yellow, brown or gray, or relatively lighter or darker, than other people's due to their genetic makeup.
    [Details]

  • Tetracycline (and related antibiotics) -

    Tetracycline tooth staining is usually yellow-brown (or possibly blue-grey) in color.
    [Details]

  • Fluorosis (fluoride) -

    Fluorosis staining results in chalky-white (or possibly brown) spots, patches or lines dispersed across a tooth's surface. These blemishes may also show evidence of tooth-surface pitting.
    [Details]

  • Internal tooth changes / Root canal treatment -

    Generalized brown or gray staining can be caused by changes that have occurred within a tooth's nerve space. This process can be triggered by events such as trauma, or needing (or having had) root canal treatment. Only those teeth directly affected by the event (often just a single tooth) become discolored.
    [Details]

  • Tooth decay -

    Different stages of cavity formation can result in white, yellow, brown or black discolorations. The tooth's surface will have lost its sheen and may show evidence of damage.
    [Details]

  • Deteriorated dental restorations -

    Deteriorated or failed dental work can cause yellow, brown, gray or even black areas of tooth discoloration. The outline of the restoration is often visible and there may be associated decay.
    [Details]

  • Surface staining / Poor oral hygiene -

    The accumulation of debris on the surface of your teeth can result in white, yellow, tan, brown, black, or possibly even green discolorations. This type of tooth staining should not be confused with those where the tooth itself has undergone a color change.
    [Details]


Details about different types of tooth discoloration.

A person's teeth will tend to darken over time.

A person's teeth will tend to darken over time.
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A) Staining caused by products you consume.

People who have a regular and continued exposure to chromogenic agents such as tea, coffee, cola, red wine or tobacco products will usually find that their teeth become dingy-looking or yellowed over time. In extreme cases, they may even take on a burnt-orange or brown tint.

  • This staining effect is caused by dark-colored compounds in the consumables (like the tannins found in tea and coffee or nicotine in tobacco products) that become trapped within the person's tooth enamel.
  • Other agents, such as blueberries, cherries, cranberries and soy sauce, are also known to cause this same effect.
  • As a rule of thumb, if you regularly consume something would stain your clothes, it has the potential to stain your teeth too.

It's a cumulative effect.

The degree of discoloration that forms generally corresponds with the regularity and level of exposure that the person has to the agents that have caused it.

Note: You may be able to minimize the effects of chromogenic foods by brushing immediately after consuming them. For beverages, try rinsing with water immediately afterwards or else drinking through a straw.

▶ Normal tooth dinginess and yellowing - How is it treated?

B) Systemic exposure to medicinal compounds (tetracycline, fluoride).

If a child ingests (swallows) elevated levels of some compounds during that time frame when their teeth are developing, the composition of the mineralized tissues of their teeth (enamel and/or dentin) may be altered as they form.

If so, this can change their optical properties, thus affecting the color and appearance of the teeth.

These types of discolorations can be:

  • Generalized (has affected the appearance of the entire tooth) - A result of continuous, prolonged exposure.
  • Appear as individual (although frequently multiple) splotches, patches, lines or ribbons of stain - A result of repeated, short-term exposures.

The exact type or pattern of staining that occurs simply depends on: 1) The level of exposure. 2) Exposure duration. 3) What portion of the tooth was forming during that time frame when the child's exposure took place.

Teeth that have tetracycline staining.

Teeth that have tetracycline staining.
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1) Tetracycline.

One medication that's well known for causing tooth discoloration is the antibiotic tetracycline. The related compounds minocycline and doxycycline can too. These compounds become incorporated in the tooth's enamel and dentin, and as a result changes their color.

This type of staining:

  • Is typically yellow to yellow-brown in color, although it can have a blue-grey tint instead.
  • The discoloration may affect the entire tooth (as a result of prolonged exposure) or be band-like (if the medicine was administered in courses).
  • A diagnosis of tetracycline staining can be confirmed by using an ultraviolet light (a "black" light), which makes the teeth fluoresce.

Prevention.

As a standard rule, tetracycline (and related antibiotics) should not be prescribed for children eight years and younger, or for pregnant women. (All of these instances involve time periods when a child's teeth are forming.)

Staining with adults.

The long-term use of tetracycline and minocycline has been reported to cause tooth discoloration even in adults. This is a point long after tooth formation has been completed.

This occurs in about 3 to 6% of cases and can affect the root and/or enamel covered portion of the teeth. For this reason, the chronic use of these medicines should be avoided if possible. (Sanchez 2004)

▶ Tetracycline staining - How is it treated?

Teeth that have fluorosis staining.

Fluorosis tooth staining.
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2) Fluoride (fluorosis).

An appropriate exposure to fluoride can provide some very significant anti-cavity benefits. But if a child ingests an excessive amount during that time period when their teeth are developing, a type of tooth staining termed "fluorosis" can result.

It can take the following forms:

  • With mild cases, the resulting blemishes are lusterless, chalky-white patches or streaks that run across the surface of the teeth.
  • In moderate cases, the color of the staining can be yellow or even brown.
  • In the most severe instances, the surface of the affected teeth can be pitted and the teeth themselves malformed.

The blemishes are due to the fact that the elevated level of fluoride interferes with the normal function of the cells that create enamel during tooth development.

The pattern of the discoloration is frequently bilaterally symmetrical (has affected corresponding teeth, in a similar way, on both sides of the mouth). This is because these were the portions of the child's teeth that were forming at the time of the exposure.

Prevention. - We discuss fluoride precautions here.

▶ Fluorosis staining - How is it treated?

C) Age-related darkening.

It's normal for a person's teeth to darken as they age. Some of this can be attributed to the effects of chromogenic agents such as coffee, cola and tobacco products (see above). But there's another reason why it occurs too.

Tooth enamel is translucent.

The way light reflects in and out of a tooth.

What we visualize as the color of a tooth stems from the way it reflects light.

  • Light penetrates through a tooth's translucent enamel layer.
  • When it strikes the tooth's opaque dentin underneath, it's reflected back out.

Anything that alters the degree of translucency of the enamel or the color of the dentin will change the apparent color of the tooth.

  • With age, the thickness of a tooth's enamel layer thins out, thus revealing more of the darker dentin that lies underneath.
  • The color of a tooth's dentin tends to change over time. It typically becomes darker as more of it is created within the tooth (termed secondary dentin formation) due to normal physiologic and reparative processes.

▶ Age-related tooth discoloration - How is it treated?

A smile with naturally dark teeth.

These teeth have a dark baseline color.
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D) Genetic factors. / Inherent baseline color.

Due to your genetic makeup, your teeth may be naturally lighter, or darker, than other people. There can also be color variations that are obvious yet normal. Some people have teeth that tend to be more blue-grey, others more yellow-brown.

Using a dental shade guide.

Documenting a patient's shade.

This range of normal is why, when you have a porcelain crown or white filling placed, that your dentist gets out their "shade guide."

It allows them to document the precise color of your teeth, as compared to the full range of shades that human teeth usually are.

Your dentist can then request that your crown be made with porcelain that's your shade, or use a filling material that's been made to match your color.

▶ Naturally dark teeth - How are they treated?

Beyond normal variations, a person's teeth may be affected by genetic disorders and inherited diseases. These may involve color abnormalities, as well as tooth shape and formation/structural issues.

E) Internal tooth changes. / Individually darkened teeth.

Teeth whose nerve tissue has undergone some degree of change, or have had root canal therapy to treat a condition, frequently darken.

The discoloration may be:

  • Yellow-brown to brown-gray.
  • In some cases, it may have a pink to purple hue.
  • The staining may be uniform, or most intense and darkest nearest the gum line.
A tooth that needs root canal treatment.

This tooth needs root canal treatment.
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As an explanation, some aspects of the staining may be due to:

  • The release of iron pigments from decomposing red blood cells inside the nerve space of the tooth (they contain the iron-rich compound hemoglobin). These dark pigments penetrate the tooth's dentin layer, thus causing it to darken.
  • In response to trauma, new layers of dentin may be deposited within a tooth's nerve space. This decreases the overall translucency of the tooth, thus making it appear darker.

Note: If a single tooth has darkened, especially one that has a history of trauma (even many years before), it may be an indication that the health of its nerve tissue has been seriously compromised. For this reason, any individually darkened tooth should always be evaluated by a dentist.

▶ Individually darkened teeth - How are they treated?

F) White-spot lesions. / Tooth decay.

A white spot lesion at the gum line of a tooth.

White-spot lesions often form right at the gum line.

If you notice a new chalky-white blemish on your tooth, especially one located right at the gum line, it may have formed due to poor oral hygiene.

These discolorations are called white-spot lesions and they're the earliest visible sign of cavity formation.

  • They form in those areas where dental plaque has been allowed to remain on a tooth's surface for extended periods of time.
  • Common locations are right at the gum line and around orthodontic brackets.

While they are a stage of cavity formation, they may or may not require attention.

As general guidelines:

  • If the enamel surface of the lesion is still hard and smooth, corrective treatment may not be needed.
  • If its surface is soft or has started to deteriorate, a filling will need to be place.

Note: Only your dentist has the qualifications needed to make this determination.

▶ White-spot lesions - How are they treated?

Tooth discoloration caused by tooth decay.

Discoloration caused by tooth decay.
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Cavities.

More advanced stages of tooth decay are typically yellow-brown to black in color.

  • The tooth's surface may show some type of damage or void in the area of the discoloration.
  • In other cases, the tooth's darkened surface is an indication of decay that lies underneath it. (See picture.)

These types of lesions need immediate treatment by your dentist.

G) Dental work.

Some of the color issues a person notices with their teeth may involve their existing dental work.

A deteriorated and stained dental filling.

A deteriorated and stained dental filling.
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1) White dental fillings.

It's the nature of white fillings to discolor as they age. The whole restoration may darken uniformly. Or stain may accumulate just at its edges.

Solutions.

As a general rule, teeth whitening treatments won't change the color of existing dental work (with a few exceptions). So, in the case of white fillings that no longer match, the only solution is to have your dentist replace them.

2) Silver dental fillings.

Over time, metal (amalgam, "silver") fillings tend to stain the tooth structure that surrounds them. This discoloration usually has a gray-blue tint and can become quite dark.

Solutions.

Teeth whitening treatments cannot be expected to resolve this type of issue. The only solution is to have some type of replacement dental restoration placed.

Because the natural teeth have darkened, these dental crowns no longer match.

The color of these dental crowns (#1, #3) no longer match.
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3) Dental crowns.

There can be times when the color of a person's existing dental work has not changed but the shade of their natural teeth has, thus creating a mismatch.

This is especially common in situations where dental crowns are involved. The glass-like nature of porcelain will not pick up stains like tooth enamel tends to.

That means, as a person's natural teeth undergo a gradual staining process, the dental crown that matched its neighbors perfectly when it was first place will eventually end up looking too light.

▶ Mismatched dental crowns - How are they treated?

H) Surface stains.

Surface stain is discoloration that has built up on the exterior of a tooth. The tooth itself is still the same color it has always been.

It's generally due to the accumulation of dental plaque, calculus (tartar) and assorted debris. Its formation is typically associated with lax or infrequent oral home care.

  • It's usually heaviest on that part of the tooth that's nearest the gum line.
  • It can be yellow, tan, or brown in color.
  • In extreme cases, it may be black or have a greenish tint.
  • It can be so adherent and thin that it seems to be a part of your tooth. In other cases, it may have an obvious thickness that's either hard or soft (or a combination of both).
  • Its color may be influenced or enhanced by the color of the consumables (foods, beverages, tobacco products or oral rinses (like chlorhexidine)) your teeth are exposed to.

Solutions.

While whitening treatments may have a favorable affect on this type of discoloration, they're not the needed solution. This type of stain should be removed via a professional dental cleaning. Then, improved oral home care (brushing and flossing) should be able to keep it from reforming (or at least not as quickly).

Note: The presence of surface staining and the confusion it causes with understanding why a tooth has discolored is one reason why a dentist will want to perform a dental cleaning before initiating any type of bleaching treatments.

 

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