White-spot lesions : The earliest visible sign of tooth decay.
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.
Gum line White Spot lesions.
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.
- 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 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 loose some of its mineral content. This includes both hydroxyapatite crystals (enamel's dominant building block) as well as calcium, phosphate and other ions. (AlShehri 2016) [page references]
As this damage takes place the enamel undergoes changes.
- The appearance of its surface looses its shine and gloss and takes on a lighter in color chalky-white appearance.
- The surface of the lesion, its "lid" (the top 2 to 50 microns, which is less than the diameter of a human hair), remains hard but due to the loss of mineral content becomes more porous.
- The tooth structure lying underneath underneath the lid experiences mineral loss on the order of 30 to 50%.
d) How long does it take a white spot 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 (Harrell 2016, Arruda 2012).
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. We explain this phenomenon in detail here.
- 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?
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).]
White spot lesions that have formed around orthodontic brackets.
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.
Arruda (2012) and Dixon (2009) reviewed studies that had evaluated the prevalence of white spot lesions among orthodontic patients.
White spot lesions resulting from poor home care while wearing braces.
- 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 2012)
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 2012)
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.
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 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 2009) (Fluoride products must be used appropriately. Their recommendations and directions must be followed.)
A way of avoiding the need for patient compliance with high risk patients is the application of fluoride varnish. For example, some studies have evaluated its use with patient wearing 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 a temporary discoloration of the teeth and gums (the varnish has a slight tan color).
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. (AlShehri 2016)
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 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 is to see if the tooth's surface is still hard, smooth and intact.
- Your dentist will 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. (Characteristics of healthy tooth enamel.)
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.
a) Some areas may not require any treatment.
After their evaluation, your dentist may decide that just minimal damage has occurred 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 pickup 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.
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. (AlShehri 2016)
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% (Dixon 2007).
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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