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What are dental Sealants?

A dental sealant is resin placed in pits and fissures of molar teeth to prevent cavities.

A correctly applied sealant 10 years after placement. Note that the sealant (the white areas) is barely visible in the tooth.

Dental sealants are resin coatings resembling white nail polish (sometimes clear, or colored) that are applied to deep, inaccessible pits and fissures in teeth so food can’t get lodged in them as easily.

If the pits or fissures in the teeth cannot be completely cleaned with a toothbrush, dental sealants may be recommended.

The process of placing dental Sealants

For best results and longevity, sealants are generally done this way:

  • The tooth must be free from decay, although there are studies in the dental literature that would suggest otherwise. Sealing in decay is not a good idea.
  • Tooth must be isolated from moisture, preferably with a rubber dam.
  • Existing plaque debris must be completely removed from the fissures.
  • Pits and fissures are checked with cavity detection dye.
  • Pits and fissures are acid etched to roughen the enamel surface. This produces microscopic finger-like projections across the enamel surface, into which the sealant material will flow.
  • Use of a dentin bonding agent may improve bond strength.
  • The sealant is applied as a flowable resin and hardened (polymerized), usually with a special type of curing light. When applied, the sealant must be free of bubbles. Only the etched enamel is covered. Resin extending beyond the etched area will not adhere. This over-treated area (flash) will leak and lead to future decay or premature failure of the sealant.
  • When properly placed, the sealant extends to cover the entire fissure, and is barely visible in the tooth.

Some advantages and benefits of dental Sealants

The professional dental literature is nearly unanimous in its endorsement of sealants as a safe and effective means of reducing cavities, although in general, the quality of studies is “not ideal” (ref: Cochrane Reviews).

Sealants make the tooth easier to clean, and keep food debris/bacterial plaque from accumulating in deep pits and fissures of the teeth. Note: Sealants do NOT make teeth impervious to decay.

Potential disadvantages and risks of dental Sealants

Dental sealant in this molar tooth appears intact, masking a cavity beneath it.

Figure 1: A dental sealant that appears to have been correctly placed, but may have leaked or may have been placed over decay.

If applied incorrectly, sealants can fail. It is very important that the sealant is applied properly.

Even if applied correctly, sealants may fail. Some studies show that fewer than half of the sealants that are placed remain in the teeth after 3 years.

Failed sealants may lead to bigger problems.

It is generally not possible to determine (either with a dental explorer or laser caries detection device if a sealant that appears visibly intact has failed and is leaking. This means the ability to detect cavities under a sealant at an early stage is significantly impaired.

A large cavity under a sealant that leaked.

Figure 2: A dental sealant in this molar tooth leaked and was removed, exposing a large (brown) cavity. The presence of the sealant prevented early detection of the progressing cavity with a dental explorer or laser caries detection device. The underlying cavity was discovered via X-ray only after it had grown very large.

Sealants often need to be replaced over time.

If part of a sealant comes out of the tooth, the part that remains may leave a pit as deep or deeper than the tooth originally had. Many times it is not possible to effectively isolate the tooth from mouth fluids without using local anesthetic and a rubber dam. This is especially true if the person doing the sealant is working alone, and the tooth is not fully erupted into the mouth (which is the best time to seal the pits and fissures).

Decay under failing molar tooth sealant.

Figure 3: When the decay was completely removed, the decay under a failing molar tooth sealant had progressed to a near pulp exposure and may need root canal treatment.

Parents of children for whom sealants may be recommended sometimes assume that sealing their child’s teeth makes them unaffected by tooth decay. Even with ideally placed sealants, this is definitely not the case. Too often, parents will relax their nutrition and oral hygiene standards, believing the sealants will compensate—a big mistake.

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Author: Thomas J. Greany, D.D.S. / Editor: Ken Lambrecht

This page was last updated on February 19, 2018.

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