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Since the 1980s, in the United States, the incidence of tooth decay on the smooth surfaces of teeth has declined, in part because of fluoridation becoming widespread in public water supplies and because of improved dental hygiene among the public. However, because the teeth in the back of the mouth (molars and premolars) have numerous pits and fissures on their biting surfaces, certain areas of these teeth are often difficult to clean even with vigorous tooth-brushing. To remedy this, research into dental sealants began in the 1960s, and by the early 1970s the first generation of sealants became available and were approved by the FDA.
Sealants painted over pits and fissures in the chewing surfaces of back teeth block food from being trapped and any carbohydrate like sugar being changed to acid by resident plaque bacteria and halts demineralisation and the caries process.
Fissure sealants can be forced deeper inside pits and fissures under pressure where the tooth was dissolved in acid, showing how food is forced inside even the deepest most minute pits of chewing surfaces.
Dental sealants are thin plastic coatings that are applied to the grooves on the chewing surfaces of the back teeth to protect them from tooth decay. Most tooth decay in children and teens occurs on these surfaces. Sealants protect the chewing surfaces from tooth decay by keeping germs and food particles out of these grooves.
Permanent molars are the most likely to benefit from sealants. The first molars usually come into the mouth when a child is about 6 years old. Second molars appear at about age 12. It is best if the sealant is applied soon after the teeth have erupted, before they have a chance to decay.
Applying sealants does not require drilling or removing tooth structure. The process is short and easy. After the tooth is cleaned, a special gel is placed on the chewing surface for a few seconds. The tooth is then washed off and dried. Then, the sealant is painted on the tooth. The dentist or dental hygienist also may shine a light on the tooth to help harden the sealant. It takes about a minute for the sealant to form a protective shield.
Sealants can only be seen up close. Sealants can be clear, white, or slightly tinted, and usually are not seen when a child talks or smiles.
As with anything new that is placed in the mouth, a child may feel the sealant with the tongue. Sealants, however, are very thin and only fill the pits and grooves of molar teeth.
A sealant can last for as long as 5 to 10 years. Sealants should be checked at each regular dental appointment and can be reapplied if they are no longer in place.
Dental sealants do not eliminate the need for fluoride treatment. Fluorides, such as those used in toothpaste, mouth rinse, and community water supplies also help to prevent decay, but in a different way. Sealants keep germs and food particles out of the grooves by covering them with a safe plastic coating. Sealants and fluorides work together to prevent tooth decay.
Sealants are one part of a child's total preventive dental care. A complete preventive dental program also includes fluoride, twice-daily brushing, wise food choices, and regular dental care.
Sealing a tooth is better than waiting for decay and filling the cavity. Decay damages teeth permanently. Sealants protect them. Sealants can save time, money, and the discomfort sometimes associated with dental fillings. Fillings are not permanent. Each time a tooth is filled, more drilling is done and the tooth becomes a little weaker.
Dental sealants are applied in a dentist's office. The dentist, dental hygienist or assistant first cleans and dries the tooth to be treated, then applies a slightly acidic solution on the tooth to create a rough surface that helps the sealant bond, and finally paints a thin layer of liquid plastic material on the pits and fissures of the tooth. After application of the plastic liquid, blue spectrum natural light is shone on the applied material for a few seconds to cure the plastic. Alternatively, some brands of sealants self-cure via a chemical process.
After curing, the plastic becomes a hard, thin layer covering the treated portions of the tooth. Despite the heavy pressures effected on teeth during chewing each day, dental sealants may remain effective for five years or longer, although sealants do wear naturally and may become damaged over time. Bacteria and food particles may eventually become entrapped under the dental sealants, and can thus cause decay in the very teeth intended to be protected.
In recent years, Bisphenol A (BPA) and dental sealants have been a point of discussion for researchers, dental providers, and consumers. BPA can be found in saliva in detectable amounts (micrograms) after placement of dental sealants.   The Canadian Dental Association  and the American Dental Association  have issued statements on their websites regarding BPA in dental sealants.