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Seal of Approval

April 1, 2001
Some offices are still reluctant to place sealants, but the preventive effects of third-generation materials prompt a chorus of approvals.
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During the two years of dental hygiene school, the only time I caught on sleep was in the dental materials class. In the midst of such intense courses as anatomy, biochemistry, and physiology, the dental materials class was an oasis of boredom in which all I needed to know was contained within the textbook. Why am I now writing about sealants, a dental material? I have come to the realization that sealants are the greatest preventive measure since fluoride.

Am I enthusiastic about sealants? You betcha! Applying them allows me to spend more time with kids, breaks up the routine of scaling, and more importantly, gives me a chance to do a noninvasive procedure that can prevent children from becoming fearful dental patients.

Sealants have been around since the early 1960s. The sealants on the market right now are second- and third-generation products made to have greater retention than the first generation. Sealants are basically the same plastic material as composite resins. Depending on which company's sealant you use, they can contain chemical compounds such as cyanoacrylates, polyurethanes, and bisphenol-A-glycidyl methacrylate (BIS-GMA).

Dental caries is a preventable disease. If our objective is to keep the dentition healthy and minimize the amount of restorative work needed, sealants are a viable solution. Fluoride greatly reduces smooth-surface caries, which accounts for as much as 44 percent of caries in five- to 17-year-olds. Sealants, on the other hand, protect the dentition from occlusal decay by filling in pits and fissures. A sealed surface inhibits bacterial growth, and the smooth surface makes it easier to keep teeth clean. Therefore, the tooth is less susceptible to the bacteria that cause decay.

Since occlusal decay accounts for most caries, sealants become an important preventive tool. Sealants are 95 percent to 100 percent effective in eliminating dental caries if the teeth have been sealed properly. Studies show that the second- and third-generation sealants can remain on the occlusal surface for up to 15 years.

Many dentists do not implement the use of sealants because they fear that decay may be sealed in. However, this fear is unwarranted. Studies have shown that if there is undetectable decay beginning on the tooth, sealants actually cut off the supply of nutrients and oxygen that the bacteria need to thrive. So sealants arrest the further invasion of decay and, in some cases, may even assist the remineralization of carious lesions.

By preventing decay with sealants, we help patients maintain oral health and decrease, if not eliminate, the need for anesthetic and cutting into healthy tooth structure. Also, sealants can be half the cost of a one-surface restoration and can eliminate dental fear, which, of course, is priceless.

Types of sealants

There are basically three types of sealants:

  • UV light-cured (first-generation) sealants, which are no longer made.
  • Autopolymerized (second-generation) sealants, which are mixed with a catalyst prior to application.
  • Light-polymerized (third-generation) sealants are induced with visible light source. The three advantages to using this type of sealant are:
  • No mixing, so there's less chance of creating bubbles
  • Longer working times
  • The presence of fluoride in it. Fluoride can provide an anticariogenic effect and cause remineralization of incipient caries.

Among these three types of sealants, some may be tinted opaque, or be clear, and some may be filled or unfilled. Unfilled sealants wear down with time, making it less crucial to get the occlusion perfect. It also means that the unfilled sealant is not retained on the occlusal surface as long. Filled sealants include some type of a glass such as crystalline quartz or silica. The filled sealants do not wear down, so it is necessary to be sure that the sealant is not too high.

Some sealants require refrigeration and some are stored on the shelf. Sealants are placed using many types of applicators such as direct delivery systems, gun trigger devices, and syringes. There are many choices. Trying a few different types helps decide which sealant works best for your office.

Safety issues

Amalgam leaching has been an issue in the dental community for many years. Now researchers are studying the possibility of sealant leaching. The researchers are considering whether any bisphenol-A or other estrogen-mimicking chemicals are leached from sealants. This is important because there may be a link between estrogen and breast cancer development, prostate enlargement, and other systemic health problems.

Some studies of sealant leaching show slight amounts of various estrogen-mimicking chemicals in the saliva one hour after placing sealants. Other studies have used blood samples taken from people with newly placed sealants and have found no chemicals present, implying that these chemicals are not absorbed into the human body. The studies conducted so far on sealant leaching are inconclusive because of the small number of people used in the studies, inconsistency of methods and materials used in the different studies, and lack of long-term results. Our choices right now are to place sealants where needed or wait for decay to occur and place amalgams that have been proven to leach or composite resins made with the same materials as sealants.

Preventing decay by using sealants is an important decision for the dental office. The dental community is continuing to study and research the issue of sealant leaching. Until the results are in, using professional discretion and following established guidelines are important. Organizations such as the American Dental Association, American Academy of Pediatric Dentistry, American Public Health Association, and the Centers for Disease Control and Prevention all support the use of sealants. If you are not already using sealants in your dental office, bring it up for discussion at a staff meeting.

Barbara Alexander, RDH, practices in Buffalo Grove, Ill. She is also the owner of Day and Night Desktop Writers, a graphic design company which writes and designs brochures, business stationery, dental newsletters, and office materials. She may be contacted by e-mail at [email protected].

Sealant Placement Guidelines

One important element of successfully treating with sealants is knowing when to use them. Sealants are mostly used on children ages five to 11, because occlusal decay is so prevalent during these years. Obviously, any posterior tooth that has deep pits and fissures is susceptible to decay and should be sealed whether it is a deciduous or an adult tooth.

The following guidelines can be considered before placing sealants:

  • The tooth should be fully erupted. If an operculum exists, it can make it difficult to keep the tooth dry and will decrease the retention of the sealant.
  • The patient's history of decay should be considered regardless of the patient's age.
  • Tooth morphology, such as deeply grooved teeth, should be sealed even if there has not yet been much occurrence of decay.
  • Diet should be considered and recommendations should be made to change poor eating habits.
  • Sealants are contraindicated for patients with known allergies to methacrylate, which is contained in sealant material.
  • Do not seal the tooth if there is obvious decay present.

Steps to sealant placement

  • Check tooth for decay. If some discoloration is in the pit or fissure, it should be widened to check for the presence of caries. As long as there are no carious lesions and the enamel has not been penetrated, the tooth can be sealed.
  • Clean the occlusal surface with air abrasion, air polishing, brush and water, or prophy brush and pumice.
  • Isolate the tooth with cotton rolls. Use the air and water syringe to control moisture. Salivary contamination can adversely affect the retention of the sealant.
  • Acid-etch the tooth surface. The acid etch makes the occlusal surface porous so that the sealant can bond with the enamel. Clear liquid acid etch flows better into the pits and fissures, but it also flows where you do not want it. Blue gel acid etch can be better controlled and is easily visible. After 20 to 30 seconds, rinse the acid etch off and dry the tooth, checking for a "frosty" appearance (re-etch if you do not see a frosty appearance). At this time, place dry cotton rolls to avoid contaminating the prepared tooth with water and/or saliva.
  • Place the sealant over the occlusal surface. Let cure or light-cure depending on the type of sealant being used.
  • Rinse. Check for gaps and biting comfort.