Dental sealants are thin protective coatings applied to the chewing surfaces of back teeth to prevent cavities. They fill in the tiny grooves and pits on molars where food and bacteria collect, creating a smooth barrier that’s easier to keep clean. Sealants prevent 80% of cavities in back teeth over two years, which is significant given that 9 out of 10 cavities form on those surfaces.
How Sealants Protect Teeth
Your molars have natural grooves and fissures on their chewing surfaces. Some of these grooves are so narrow that toothbrush bristles can’t reach the bottom, making them ideal hiding spots for bacteria and food particles. Over time, acid produced by those bacteria eats into the enamel and creates a cavity.
A sealant flows into these grooves as a liquid, then hardens to form a physical shield over the vulnerable surface. Bacteria and food can no longer settle into the pits, and the smooth surface is much easier to clean with normal brushing. Think of it like filling in the cracks of a sidewalk so weeds can’t grow through.
Types of Sealant Materials
The two main categories are composite resin sealants and glass ionomer sealants. Composite resin is the more common choice. It’s applied as a liquid and hardened with a special curing light. Glass ionomer sealants set through a chemical reaction on their own and have the added benefit of releasing small amounts of fluoride into the tooth over time.
There are also hybrid materials that combine properties of both types. The practical differences for patients are minimal. Your dentist will choose based on the specific tooth, the patient’s age, and how dry they can keep the tooth during application (resin sealants are more sensitive to moisture).
What the Application Feels Like
Getting sealants is quick, painless, and requires no drilling or numbing. The entire process takes a few minutes per tooth and involves several steps:
- Cleaning: The tooth is cleaned to remove any plaque or debris. A simple toothbrush works as well as a dental handpiece for this step.
- Acid etching: A mild acid gel is placed on the chewing surface for 15 to 20 seconds. This roughens the enamel at a microscopic level so the sealant can grip the tooth.
- Rinsing and drying: The acid is rinsed off for 10 to 15 seconds, then the tooth is thoroughly dried. The etched surface should look frosty or chalky. If saliva contaminates the surface at any point, the etching step is repeated.
- Applying the sealant: The liquid sealant is painted onto the grooves of the tooth.
- Curing: For resin sealants, a blue light is held close to the tooth for several seconds to harden the material. Glass ionomer sealants set on their own.
You can eat and drink normally right after. Most children tolerate the process easily since there’s no discomfort involved.
Who Should Get Sealants
Sealants are most commonly placed on children’s permanent molars shortly after they come in. The first set of permanent molars typically arrives around age 6, and the second set around age 12. Applying sealants soon after these teeth erupt gives them protection during the cavity-prone childhood and teenage years.
Children as young as 2 can receive sealants on baby teeth if those teeth have deep grooves and the child is at higher risk for decay. Adults can also benefit, particularly if they have deep grooves on teeth that haven’t developed cavities yet. The CDC notes that people of all ages are candidates. However, for people with very low cavity risk and no deep grooves, sealants may not be necessary.
Sealants are not placed on teeth that already have fillings. The evidence on sealing teeth with early-stage decay is mixed. Some studies show sealants can slow down very small lesions, but once a cavity has progressed beyond the earliest stage, a sealant alone won’t fix it.
How Long Sealants Last
Sealants don’t last forever. In a study of young U.S. naval personnel, about 88% of sealants were still intact and functional after an average of 35 months (roughly 3 years). Among the sealants that did fail, they lasted an average of 26 months before breaking down. In practice, sealants can last anywhere from 3 to 10 years depending on how well they bonded initially, the patient’s chewing habits, and whether they grind their teeth.
Your dentist will check sealants at regular visits and can reapply them if they’ve worn away or chipped. People at higher risk for cavities may need more frequent checks to make sure the seal is still intact. A partially lost sealant offers no protection on the exposed portion, so maintenance matters.
Cost and Insurance Coverage
Without insurance, dental sealants typically cost $34 to $65 per tooth, with an average around $49. The price varies by location, the type of dental practice, whether the patient is a child or adult, and the material used.
Many dental insurance plans cover sealants as part of preventive care benefits, particularly for children. Coverage amounts vary by plan, and some plans offer full coverage while others cover only a portion. Adult coverage is less common. Even without insurance, sealants are one of the more affordable preventive dental treatments, especially when compared to the cost of filling a cavity later.
The BPA Safety Question
Resin-based sealants are made from a material called BisGMA, which is chemically related to bisphenol A (BPA). This has raised questions about whether sealants expose patients to meaningful amounts of BPA. The short answer: there is a temporary spike that drops back to normal quickly.
A systematic review found that BPA levels in urine increased by 30% to 113% within 24 hours of sealant placement. In absolute terms, the increase ranged from about 0.71 to 2.73 nanograms per milliliter, which are very small amounts. By 14 days after treatment, BPA levels had returned to baseline and stayed there at the 6-month follow-up.
The health significance of this brief exposure remains an open question. There are no established thresholds defining what level of BPA exposure is harmful, and the FDA does not require human biological toxicity testing for these materials. The American Dental Association considers sealants safe, and the cavity-prevention benefits are well established. If BPA exposure is a concern, your dentist can use a glass ionomer sealant instead, which does not contain BPA-related compounds. Some dentists also reduce exposure by wiping the sealant surface with gauze immediately after curing, which removes the outermost layer where most BPA release occurs.