Dental Sealants: The basics.

- What are they? / How do they work? / Which teeth should get them? / At what age? / How long do they last? / How effective are they? - statistics / What to do if one comes off.

A picture of two teeth that have dental sealants.

Dental sealants fill in the grooves (pits and fissures) of teeth.

Tooth Sealants -

a) What are they?

A dental sealant is a thin plastic coating (clear or white) that's bonded into the pits and grooves of a tooth. (Dentists formally refer to them as "pit and fissure" sealants.)

They're most frequently placed on the chewing surface of teeth (where most of a tooth's grooves lie). But they can also extend onto their cheek or tongue sides too (either as a continuous or separate piece) depending on what additional pits and fissures are found there.

There's nothing new about the use of sealants. Dentists have been placing them since the late 1960's.

b) Why are they needed?

Sealants help to protect teeth from the formation of tooth decay.

The general problem.

As compared to its smooth surfaces, a tooth's pits and fissures (grooves) tend to trap debris (dental plaque, food particles, etc...).

And when they do, it places them at risk for cavity formation.

The remedy.

A dental sealant fills in a tooth's grooves so debris can't accumulate. (See diagrams below.)

  • It's been estimated that 80% of tooth decay in school children occurs in pits and fissures.
  • However, these areas only make up about 15% of a tooth's total surface area.
  • So by protecting just 15% of a tooth with a dental sealant, you can substantially lower a child's overall risk for cavities.

(Krachner 2016) [page references]

When compared to the expense and effort of having a cavity form and then a filling placed, placing dental sealants is a very simple and cost-effective measure.

c) Who should get them?

  • Most sealants are placed on the teeth of children (see below for at what age, which teeth, etc...).
  • However, any person who has a tooth that could benefit from this type of protection, no matter what their age, can and should receive one.

It's the susceptibility of the tooth and not the age of the patient that should be the prime consideration.

Preventing
cavities using:

d) When should they be applied?

Sealants are considered a preventive measure, as opposed to a corrective one. (Filling placement is typically a corrective measure.)

Ideal conditions for sealant placement.

The most predictable scenario for the use of a sealant is one where it is placed before any sign of a cavity has had a chance to form.

For this reason, once a need has been identified, it's a good idea to have a tooth sealed as soon as is reasonably convenient.

Acceptable conditions for placement.

Even if vague signs of cavity formation have started to appear (referred to as incipient or non-cavitated decay), a dentist may determine that it's still acceptable for a sealant to be placed. This simply needs to be determined on a case-by-case basis.

The general idea is that the tight seal of the sealant over the bacterial colony responsible for forming the lesion will cut off its food supply, thus arresting, or at least retarding, the progress of the decay process.

One study (Heller 1995) evaluated teeth with incipient decay over a 5 year period.

  • Only 11% of the teeth that received sealants developed a cavity. (These would be cases where the sealant inhibited rather than arrested the decay.)
  • In comparison, 52% of teeth that did not receive the protection of a sealant had a cavity form.
Takeaways from this section.

This information suggests that the risks associated with a "wait and see" approach might be acceptable.

For example, in cases where a child's oral home care seems reasonable and family finances are a consideration, a decision might be made to not place sealants now but instead watch for signs of incipient decay formation.

If and when that occurs, a sealant is promptly placed. (One has to keep in mind that this approach relies on the regular evaluation of the patient by a dentist.)

In cases where the child's home care is lax, or family finances are not a concern, it probably makes more sense to just go ahead and seal the tooth.

How do dental sealants work?

In a nutshell, a sealant creates a smoother tooth surface. One that's easier to clean and therefore more resistant to the formation of decay.

a) Background.

Cavities are caused by bacteria that live in dental plaque (the white film that forms on teeth). Tooth brushing helps to prevent decay by scrubbing this film away. (More information - How do cavities form?)

Animation showing why deep tooth grooves that can't be effectively brushed should be sealed.

Grooves that are too narrow for toothbrush bristles to clean should be sealed.

The problem is, deep tooth grooves can be hard to clean.

Some teeth, especially molars, have grooves (pits and fissures) on their chewing surface and sides that are narrow and deep.

And in these cases, when the person brushes their teeth, some of the dental plaque that has accumulated on them is left behind.

That's because the individual bristles of their toothbrush are too large to reach into the depths of their tooth's pits and fissures (as illustrated in our graphic). And because some plaque is left behind, the tooth remains at risk for cavity formation.

Animation illustrating that dental sealant is bonded into the grooves of a tooth.

Dental sealant is bonded into the grooves of a tooth.

b) How a tooth sealant solves this problem.

By bonding dental sealant into the grooves of a tooth, a dentist can make a tooth's surface smoother.

As a result, there are no longer any locations where the bristles of a toothbrush can't reach and clean. The tooth is now at less risk for developing a cavity.

Animation illustrating how a sealant helps to protect against tooth decay.

Sealants can help to protect vulnerable tooth locations.

c) A side benefit of sealing a tooth.

Another difficulty associated with teeth that have deep pits and fissures is the thickness of the enamel that lies at their base. It may be comparatively thin (see our graphic).

That means not only does the groove make it more likely that decay may form but if it does it will have an easier time of penetrating into the interior of the tooth. Placing a dental sealant in time can prevent this scenario.

d) Fluoride release.

Some sealants are formulated with fluoride. Its release, right at a tooth's surface, can help to lower its chances for decay.


Should sealants always be placed?

Not all teeth require the protection that dental sealants can provide. In fact, the American Dental Association's Council on Scientific Affairs states that they should not be looked on as a "standard of care" (as in everyone should get them) but instead a useful tool that needs to be considered on a case-by-case basis. (Beauchamp 2008)

After an examination, your dentist can report to you what they feel is indicated.

 

Narrow tooth grooves tend to accumulate stain and debris.

Picture of deep tooth fissures that have accumulated stain.

Narrow, unbrushable tooth grooves place a tooth at increased risk for cavity formation.

Factors that a dentist will look for and consider.

  • Any tooth that has pits and fissures that tend to accumulate debris is a candidate for a sealant.

    It literally is the shape of the grooves that the dentist evaluates. Teeth that have deep and narrow ones will have a more urgent need than teeth whose grooves are naturally shallow and rounded.

  • Back teeth (premolars and molars) typically have the most pronounced grooves and therefore are the most-sealed.

    But any kind of tooth might have some type of surface irregularity that tends to trap debris and therefore makes it a good candidate for this procedure.

  • Beyond just tooth anatomy, a dentist will evaluate additional factors that may place the person at elevated risk for pit and fissure decay.

    This can include: the overall amount of dental plaque they find present on the person's teeth, the types of foods eaten and eating habits of the person, the amount of decay that's been experienced in the past, and the person's current exposure to an appropriate amount of fluoride.

  • As explained above, any tooth that has already developed incipient decay is certainly a candidate for a sealant. Placing one may avoid the need for a filling later on.

At what age should sealants be placed? On which teeth?

While a dental sealant can be placed on any tooth at any age, most are placed on the teeth of children. For this group, certain rules of thumb apply.

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Age-related considerations.

  • A tooth must be kept dry during sealant application. That means the portion of the tooth receiving treatment must be erupted through its surrounding gum tissue enough that this is possible.
  • The patient must be able to provide at least some degree of cooperation.

The specific age at which this combination of events occurs will vary from tooth to tooth, and child to child. It typically rests upon the dentist to make a recommendation as to when any specific tooth can and should be sealed.

General guidelines.

  • Permanent 1st molars (6-year molars) - These teeth usually come in between ages 5 to 7 years. At this age, most children are cooperative enough to allow this procedure to be performed, so as soon as the molar has penetrated its gum line far enough a sealant can be placed.

    Common recommendations: 1st molars are probably the most frequently sealed teeth and it's easy to understand why. While they are intended to serve a child for their entire lifetime, they come in at an age when eating and brushing habits are typically lax. In fact, molars are the type of tooth that's the most likely to experience decay.

    Most dentists probably prefer to error in favor of recommending sealants for 1st molars, as opposed to not. A properly placed and maintained dental sealant has no potential to cause harm, whereas not placing one may have consequences.

  • Permanent 2nd molars (12-year molars) - These teeth typically come in between ages 11 to 14 years. At this age, there should be little concern about patient cooperation, so it's just a matter of waiting until the tooth has erupted far enough through the gums to apply the sealant.

    Common recommendations: As compared to age 6, at age 12 years the dentist will have a clearer picture of their patient's risk for cavities.

    For children who have comparatively shallow tooth grooves, display good eating and oral homecare habits, have no history of decay and dental costs are a concern for the family, a dentist might not feel strongly about the need for sealant placement on the child's 2nd molars.

    For families where finances are not a concern, since statistically molars are the teeth most likely to experience decay, protecting one from square one might be something they're eager to do.

  • Other permanent teeth. - A recommendation for sealant placement on other types of permanent teeth is typically made on a case-by-case basis.

    Premolars (bicuspids) - These teeth may very well display the same deep groove anatomy of their neighboring molars. If so, sealants should be placed. After molars, bicuspids are the teeth most likely to receive a sealant.

    Incisors - While relatively uncommon, front teeth may need the protection of a sealant. For example, upper incisors are well known for having a pit on their backside that is often deep and accumulates plaque.

  • Baby teeth (deciduous teeth) - While there is no question that baby teeth are important (they hold space for their permanent replacements), recommendations for protecting them tends to vary.

    Besides just pit and groove depth, a number of other issues must be considered too. This includes: available patient cooperation, how long before the tooth will fall out on its own, etc... You'll simply need to seek your dentist's advice on this matter.

  • Teeth of adult patients - Any permanent tooth can be sealed, at any time.

    Common recommendations: A need for this type of protection for adults not all that common.

    In most cases, one would expect that a tooth whose deep pits and fissures place it at great risk for cavity formation would have already developed decay by the time adulthood is reached. Of course, there can always be exceptions. This issue simply needs to be determined on a case-by-case basis.

Takeaways from this section.

Dental sealants are amazingly cost effective in those outcomes where they have prevented decay (see our Costs page). But in instances where a cavity never would have developed, they just represent an expense.

Factors associated with permanent molars of children usually make them obvious candidates for sealant placement, so even a generalized recommendation is easy to make.

But for other teeth, and other ages, factors vary more widely. Determining the value or cost-effectiveness of protecting these teeth is more difficult to determine.

How long do dental sealants last?

Sealant loss.

A dentist would probably consider any sealant that remained intact for 3 to 5 years to be a success. However, any that require replacement or repair sooner than that should not necessarily be considered failures. Any length of time that one remains in place is a time period during which its tooth is protected.

  • Feigal's (1998) review of published dental literature estimated a sealant loss rate (including partial loss) on the order of 5 to 10% per year.
  • A study by Dorantes (2005) came to similar conclusions. At one year, sealant retention was found to be 72%, with declines of approximately 10% found annually over the next 3 years.
  • Jodkowska (2008) evaluated sealant loss rates over a 15 year period and determined that at this point 22% of teeth still maintained complete retention and 35% partial retention.

As confirmed by this last study, it's somewhat common that a dentist will see evidence of sealants placed during childhood still intact on their adult patient's teeth.

Sealant wear.

Sealant wear doesn't necessarily equate with a loss of protection. Even when it occurs remnants of the plastic usually remain in the depths of the tooth's grooves, thus still providing its preventative function.

a) Sealant maintenance is an important factor.

A dental sealant can only provide optimal protection if it's fully intact.

  • If you notice that any portion, or even possibly all, of a sealant has come off, you should let your dentist know.
  • During each of your regular dental checkups, your dentist will evaluate the integrity of your sealants and let you know if any of them require repair.
Studies evaluating sealant protection vs. retention.
  • A study by Mertz-Fairhurst (1984) concluded that the decay rate for molars with partially retained sealants was essentially the same as those that never received one.
  • In comparison however, a study by Jodkowska (2008) involving 360 children followed over a 15 year period found that 15% of teeth with partially retained and 31% of teeth with complete sealant loss developed cavities.

    This implies that even poorly maintained sealants still provide more benefit for teeth than never having placed them at all. (FYI: 7% of teeth maintaining complete sealant retention developed decay.)

  • Griffin (2009) designed a study whose purpose was to specifically evaluate the consequences associated with partially and fully lost sealants. Its conclusions were: "Teeth with fully or partially lost sealant were not at a higher risk of developing caries than were teeth that had never been sealed."

It's important to note that each of these studies confirms the benefit of periodic evaluation, with repairs made as needed to keep the patient's sealants fully intact. The Jodkowska study used checkup intervals of every 6 months for the first 2 years, followed by evaluations once every 12 months.

b) A second try might be more successful.

One reason why a sealant might come off is because the dentist wasn't able to keep the tooth dry during its placement. This can certainly be the case where a child patient has been uncooperative.

As the child becomes older and more mature, even by several months or a year, it's quite possible that a second attempt to seal the tooth will be more successful.

Takeaways from this section.

There's a bit of awkwardness with this aspect of sealing teeth. Generally, it's better to place one sooner than later. But if an attempt is made too early, the dentist might have a difficult time because they don't have full patient cooperation.

The latter can make loss (partial or full) more likely. But, on the other hand, if a tooth is left unprotected for too long decay may form.

This quandary is simply something you'll need to iron out with your dentist. One question you'll need to ask is what costs are involved with sealants that fail prematurely (like during the first few months or year after first attempted). Will the dentist simply replace it, or will a new charge be made?


How effective are sealants in preventing cavities? - Research findings.

Numerous studies have documented the preventive benefit of placing dental sealants. Here's a sampling:

  • Jodkowska (2008) - This study followed the dental histories of 360 seven to eight year old children over a 15 year period.

    Findings: Sealing all of a child's 1st molars resulted in a 36% reduction in the total number of cavities ever experienced by them. When all posterior teeth had been sealed (molars and premolars), the overall reduction in cavities was found to be 54%.

  • Bravo (2005) - This study evaluated 36 six to eight year olds over a 9 year period. While participating in the clinical aspect of the study, the children had sealants placed on their permanent 1st molars. Then, for the following 3 years, periodic observation and needed repair were performed. After that, the study itself provided no further checkups or repair.

    At 9 years, 27% of the sealed teeth vs. 77% of the 1st molars in the control (unsealed) group had developed occlusal decay (decay on the part of the tooth that sealants protect), for a comparative reduction of 65% (sealed vs. unsealed).

  • American Academy of Pediatric Dentistry (2002) - This organization published a paper in conjunction with their Pediatric Restorative Dentistry Consensus Conference.

    Nine randomized controlled trials involving permanent molars and 2 to 3 year follow-up periods were evaluated, documenting a 76% reduction in occlusal cavities for sealed teeth.

(Cvikl 2018)

 

Written by: Animated-Teeth Dental Staff

Content reference sources.


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Comments

No good.

Beware of having this. My sister's child had a sealing on a bottom molar and it got a cavity inside the tooth anyway. It went until it killed the nerve. The dentist took now responsibility.

Barb

While we don't doubt that what you state is factual, placing dental sealants is a valuable preventive tool. In defense of this procedure, we would like to explain the following points.

In regard to creating tooth protection, placing a sealant is the first step. The second step (as discussed above on this page) is monitoring its integrity during regular checkups over the following months and years.

The hope is that through regular monitoring the dentist will be able to detect any deficiency [sealant loss (whole or partial), leakage] early on before any decay has started. If instead decay is discovered, then a filling is promptly placed. With regular checkups, having a cavity get so out of hand that a deep cavity has formed that has affected the tooth's nerve could only be considered to be the rare exception.

As a second line of defense, even if periodic evaluation of the sealant's surface didn't reveal problems developing underneath, routine x-ray evaluation (via taking bitewing x-rays) should detect any cavity formation long before it gets out of hand.

[Having sealants doesn't negate the need for periodic x-rays. That's because x-rays are used to detect cavities in additional areas that sealants don't protect (primarily those tooth surfaces that touch adjacent teeth, use the bitewing link above for examples).]

Finally, in regard to the dentist's position, if regular checkups and x-rays weren't involved then they weren't given the opportunity for monitoring that's needed. Beyond that, it's difficult to know how much responsibility they should have taken.

Generally, it seems even with sealant failure of some sort (partial or full loss) the tooth isn't at greater risk for decay than it would have been if one had never been placed. (See studies discussed above regarding both of these points.)

While obviously we don't know the details of your nephew/niece's case, it seems easy to state that what has occurred seems far from the norm. And while a tragedy for the child and tooth, it would be a disservice to others to suggest that this isn't a safe and reliable form of cavity prevention. In the vast majority of cases it is, and it provides a valuable service that can't be duplicated by any other type of dental treatment.


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