White-spot lesions : The earliest visible sign of tooth decay.

- Reasons why they form. / Locations where they occur (near the gum line, around dental braces). / Pictures. / How to prevent them. / Treatment solutions.

1) What are white-spot lesions?

White spots that develop on tooth enamel are usually an indication of tooth decay formation. They're the first readily visible sign that an area is developing a cavity.

Another term dentists use for white spots is "incipient lesions," meaning areas of decay that are just beginning.

a) What do the lesions look like?

True to their name, affected areas have an opaque, chalky-white appearance that's lighter in color than neighboring undamaged areas.

b) Where do they form?

Since they're caused by the tooth decay process, you can expect to find white spot lesions in those areas where dental plaque has been allowed to accumulate and persist.

 
Picture of white-spot lesions on teeth.

White spot lesions are frequently found near the gum line (areas that have been difficult to keep plaque-free).

Likely locations:
  • It's very common to see them form right at a tooth's gum line, which is an area people often miss when brushing. (See picture above.)
  • In a similar fashion, if you're not flossing well enough (either not as often as you should or you aren't being effective) you may discover that white spots have formed in areas where your teeth touch together.
  • And since cleaning around dental braces can be difficult, they frequently form next to where a person's orthodontic brackets are bonded to their teeth (see picture below). (We discuss the increased risk of white spot lesions with orthodontic patients here.)

 

c) What causes white spot lesions to form?

They're caused by enamel demineralization (decalcification), which is the process that causes tooth decay and ultimately cavities. It occurs when a tooth's surface is exposed to acidic waste products produced by oral bacteria living in dental plaque.

How does decalcification affect the enamel?

As the demineralization process takes place, the affected area begins to lose some of its mineral content. This includes both hydroxyapatite crystals (enamel's dominant building block), as well as calcium, phosphate and other ions.

  • Initially, the greatest amount of damage takes place at a level just below the tooth's surface (10 to 15 microns, which is about 1/10th the width of a human hair).

    The explanation for this lies in the fact that the surface enamel of teeth is typically far more resistant to the demineralization process than that which lies deeper, and thus remains less affected. (The enamel's history of exposure to fluoride can play a big role in creating this "harder" surface effect.)

  • As the surface and subsurface changes progress, they affect the optical (light-handling) properties of the enamel. As a result, the surface of the affected area starts to lose its shine and glossiness, and overall the lesion begins to take on a lighter, chalky-white appearance. (Hence the name white spot lesion.)

 

  • As the demineralization process progresses underneath, the tooth's surface becomes an impromptu "lid" over the lesion (2 to 50 microns in thickness). As more and more mineral content is lost from it, it's original intact surface becomes ever more fragile and porous.

    The tooth structure that lies underneath the lid (the most affected area) can experience mineral loss on the order of 30 to 50%.

Section references - Dean, Fejerskov

White spot lesion vs. cavity - What's the difference?

While a relatively arbitrary differentiation, as long as the surface lid of the affected area retains enough structural integrity that it remains intact (including when tested by your dentist with their tools), the lesion is still considered a white spot lesion.

If instead portions of the lid have broken down and have resulted in a substantial break in the continuity of the tooth's surface or an outright hole, the lesion is then considered a cavity.

The importance in differentiating between these two states lies in what treatment options are considered possible and appropriate. (This entire subject is discussed in more detail below.)

d) How long does it take white spots (incipient lesions) to form?

The process of demineralization occurs anytime a tooth's enamel surface is subjected to an acidic environment (like that which exists underneath a coating of dental plaque). But it takes a period of time before enough decalcification has occurred before it has affected the tooth's enamel to the point where it is visible.

Studies involving patients with braces have shown that white spots can form in as little as one month.

Section references - Arruda, Harrell

e) Similar looking lesions.

Another type of dental white spot is caused by an elevated systemic exposure of fluoride during childhood tooth development. This is an entirely different type of lesion than the one discussed on this page. It is referred to as fluorosis (use link for more details).

Differential diagnosis.
  • White spots due to fluoride consumption will always have been present on the tooth from the day it first came in.
  • In comparison, those related to cavity formation develop on areas of enamel that previously looked normal.

 

2) White spots and dental braces.

The formation of white-spot lesions can be especially troublesome for dental patients who wear conventional bracket-and-wire (fixed) braces.

a) What's the basis of this concern?

If not kept plaque-free, white spot lesions will tend to form around orthodontic brackets.

Animation illustrating white spot lesions that have formed around braces due to dental plaque accumulate.

When the brackets are removed, the white spots will spoil the appearance of the teeth.

The basic problem.
Wearing fixed appliances makes it exceedingly difficult for a person to clean their teeth. And if dental plaque is allowed to accumulate and persist around their brackets (the part that's bonded directly to their teeth), white-spot lesions may form.
[Studies show that placing braces correlates with an increase in the patient's level of dental plaque accumulation and a higher percentage of the types of bacteria that cause decalcification and therefore cavities (Harrell 2016).]

Section references - Harrell

The added complication.

With dental braces, there's an added problematic twist. The tooth enamel that lies underneath the bracket will remain unchanged.

That means when the braces are finally taken off, the color difference between the damaged and undamaged areas may be very obvious (see pictures).

b) White spot / Dental braces incidence rates.

In separate papers, both Arruda and Dixon discussed studies that had evaluated the prevalence of white spot lesions among orthodontic patients.

Picture of white spot lesions resulting from poor oral home care during braces treatment.

White spot lesions resulting from poor home care during orthodontic treatment.

  • On a whole, rates ranging from 2 to 96% were found to have been reported.
  • A much-cited study from 1982 placed the rate at 50%, whereas more recent investigations (2009 and 2007) placed it in the 73 to 95% range.
  • The patient's teeth that are most affected are typically the upper front ones (15%).
  • The teeth most commonly affected are the upper lateral incisors (23%). (The tooth with the largest white spot in our picture is a lateral.)

    Then, in descending order, the canines (eyeteeth), 1st premolars, 2nd premolars and then the central incisors. (Bourzgui)

 

How quickly do they form?
While the time needed for formation will vary with the local conditions at each specific site, studies suggest that white spot lesions can form in as little as a month. (Arruda)

Section references - Arruda, Dixon, Bourzgui


3) How do you prevent white spots from forming?

a) Better brushing.

Since these discolorations are an early stage of cavity formation, the first line of defense in preventing them is to practice effective oral home care.

Of course, doing so may be easier said than done, either from a standpoint of motivation or technical ability. (The use of an electric toothbrush may help some people with both.) But bottom line, if no plaque is present, or else is removed in a timely fashion, no white spot lesions will form.

 

b) Fluoride.

Because the presence of fluoride in saliva assists the remineralization process (the action that helps to reverse the damage caused by tooth decay), making sure you have an appropriate exposure to it can help to reduce your risk for these lesions.

Toothpaste, Oral Rinse

Using an over-the-counter fluoridated toothpaste (the best fluoridated toothpastes) or mouth rinse (like 0.05% sodium fluoride rinse) can be an effective way to get an adequate exposure. With higher-risk patients, the use of a (higher concentration) prescription product may be indicated.

Of course, patient compliance is an important factor. One study investigating this point found only 15% of orthodontic patients rinsed daily as instructed. (Dixon) (Fluoride products must be used appropriately. Their recommendations and directions must be followed.)

Section references - Dixon

Fluoride varnish.

A way of avoiding the need for patient compliance with those at high-risk is the application of fluoride varnish. For example, some studies have evaluated its use with people who wear dental braces.

  • One found a 7.4% incidence rate for white spot formation when the varnish was applied every 6 weeks vs. a 25.3% rate for the placebo group.
  • Another study found a 44.3% reduction in lesions in a group receiving regular applications.

 

Detracting from this approach is its cost (of materials, for regular application visits). It also causes temporary discoloration of the teeth and gums (the varnish has a slight tan color).

Section references - Dixon

c) ACP/CPP-ACP products.

Calcium phosphate products (including amorphous calcium phosphate (ACP), casein phosphopeptide-ACP, calcium sodium phosphosilicate, and tricalcium phosphate) release both calcium and phosphate ions that may then aid with the remineralization process of tooth enamel.

If so, their use may help to inhibit the formation of white spot lesions. The use of these types of products is not however conclusively supported by research.

Section references - Arruda

d) Consume xylitol products.

Studies have shown that introducing xylitol (a natural table sugar substitute derived from birch trees) into your diet can create a substantial anti-cavity effect.

Repairing white spot damage.

Generally speaking, anything that helps to promote tooth enamel remineralization will not only help to prevent white spots from forming but also, as discussed below, help to repair the damage that has caused them.

4) Evaluating and treating white-spot lesions.

White-spot (incipient) lesions represent a very early stage of cavity formation, and possibly one where just a minimal amount of tooth damage has occurred.

If that's the case, making a repair may not be required. But without question you need to understand this point:
  • Only an examination by your dentist can lead to a decision that any specific white spot does or does not require treatment.

Ignoring what you see or making an uninformed decision on your own can result in significant tooth damage.

 

How your dentist evaluates white spot lesions.

1) Visualization of the lesion.
The conditions under which a white spot is visible hints to its level of involvement.
  • The outline of very slight lesions will only be apparent after the tooth's surface has been dried.
  • More advanced lesions will remain obvious even when the tooth's surface is wet.

 

2) Evaluating the integrity of the tooth's surface.

Another gauge of the level of damage that has taken place that a dentist might use is to see if the tooth's surface is still hard, smooth and intact.

  • To check, they may inspect the white spot with a pointed metal tool (a dental "explorer"). As they do, they will scrape and probe its surface to see if it's still hard and smooth. (These are characteristics of healthy tooth enamel.)
  • However, nowadays it's realized that disrupting (destroying) the surface enamel of a white spot lesion by picking at it will interfere with whatever level of remineralization potential it may have had. And for that reason, this technique, if used at all, is practiced much less aggressively than it was historically.

 

3) Transillumination.
As a third test, your dentist may evaluate your tooth using a very bright light.
  • They might place a strong light source on the backside of your tooth or else evaluate how the light from their overhead clinical lamp shines through.
  • Deeper lesions (those having a greater degree of damage due to demineralization) will tend to block a greater amount of light as it passes through the tooth.

 

4) Inactive vs. active white spots.

Just as evaluating the amount of damage that has already occurred is vital, it's also important for the dentist to judge the lesion's level of current activity and potential to progress further.

  • Active lesions tend to be located in areas of continued plaque accumulation, have a characteristic dull, chalky-white appearance and evidence of surface breakdown (enamel roughness).
  • Inactive or "arrested" white spots typically have a hard intact, shiny and smooth enamel surface. They may have a brown coloration (a result of picking up stain) and are found in areas where persistent plaque accumulation is not a problem.

 

5) Additional methods.
Beyond the simplistic techniques just discussed, many dentists will have some type of specialized, high-tech device that when held to the tooth can help them to determine the current status of its white spot lesions (differentiate between a lesion that just requires minimal or conservative treatment vs. an outright cavity). However, the diversity of the types of units available leaves a discussion of them beyond the scope of this page.

Section references - Fejerskov, Dean

a) Truly incipient lesions will not require any treatment.

After their evaluation, your dentist may decide that at this point just minimal damage has occurred to your tooth and your lesion's potential for further advancement is minimal.

If so, they may not recommend any formal repair but instead suggest that relying on the natural process of tooth remineralization is sufficient for arresting the disease process and restoring the damaged enamel's strength and function.

If this solution is offered, the patient must understand that the healed lesion will forever remain as a chalky-white scar on their tooth, although its surface should regain its lost shininess. In some cases, as remineralization occurs the affected area may pick up brown staining.

You'll need to change your habits.

Keep in mind that this type of natural repair can only take place if you change the conditions that allowed the white spot to form initially.

Cavities are usually caused by some combination of ineffective brushing and flossing, and inappropriate sugar consumption. If you're not able to change these conditions, remineralization cannot be expected to occur.

Helpful products.

As mentioned above, some types of compounds help to promote the remineralization process and their use can play an important role in tipping the conditions in a person's mouth toward those of repair instead of continued destruction. This includes the use of fluoride and calcium phosphate products.

Monitoring will be required.

Since they represent an area that at least historically has been difficult for you to keep clean, any and all untreated white-spot lesions must be monitored by your dentist during regular checkups.

b) Treating minor unsightly lesions.

While some white spot lesions may not require outright repair, their appearance may be objectionable enough that some type of improvement is desired. If so, there are some relatively less-invasive remedies that might be attempted.

"Minimal" approaches for white spot repair -
1) Whitening treatments.

It may be possible to use teeth-whitening treatments to mask the appearance of white spots. As the tooth's color is lightened, its chalky-white lesion tends to become less noticeable.

The specific technique used might be an in-office or at-home (strips, trays, paint-on) one. After the treatments have been completed, the patient can then decide if additional dental work is required to satisfy their esthetic expectations.

2) Resin infiltration technique.

One newer approach for treating white spots involves first etching the lesion's surface with an acid conditioner and then bonding a flowable tooth-colored dental restorative into and over it.

The idea is that the restorative infiltrates the porous structure of the lesion, thus creating a smoother (less plaque-retentive) surface and improved esthetics. It should be stated however that this is a relatively new technique and as such its use as a long-term solution has yet to be documented.

Section references - Dean

3) Enamel microabrasion.

A procedure termed "microabrasion" offers another possible remedy. This is a process where the surface of the tooth is worn and polished down using a hydrochloric acid and pumice mixture.

One study determined that on average this technique was able to reduce the size of white spots by 83%.

Section references - Dixon

Less treatment may offer a better solution.

While none of the approaches above may give perfect results, if passable they can help to avoid the need for an outright repair (such as placing a filling or veneer), and the long-term maintenance required with it.

c) Some lesions will require repair.

If a white spot is unsightly or its surface has lost its integrity (it's soft, rough, pitted or possibly has even developed a hole), some type of repair is indicated. If so:

  • A filling is frequently used as a way of repairing or masking the damage. (Either dental amalgam or tooth bonding might be used, depending on the spot's location.)
  • With some front teeth, placing a porcelain veneer may provide the best solution toward fully restoring the tooth's appearance and function.

 

 
 
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