There are several types of coatings that can be used to prevent cavities.
Fissure sealant
A thin plastic coating painted on to the grooves and fissures of back teeth (molars and premolars) to occlude vulnerable fissures from bacteria. This preventive procedure is done after the areas to be sealed have been carefully cleaned of plaque and chemically-treated to allow the sealant to adhere to the enamel surface.
Fissure sealants are the best way to prevent cavities from forming in these hard-to-clean fissures that tend to accumulate food matter and bacteria despite thorough brushing. Some patients are just born with tooth anatomy that has pronounced and deep fissures.
Patients who benefit the most from fissure sealants are those with a history of fissure decay (you may have existing fillings on the biting surfaces of your back teeth). Fissure sealants can be placed in permanent back teeth that have started erupting in children from the age of 7 years old. However, due to the immature state of the enamel in newly erupting teeth, the sealants may not last as long as those done in older children, teenagers or adults and may need to be renewed at a later date.
Fissure sealants however, do not protect the entire tooth surface and only selectively protect the fissure areas. Smooth surfaces such as those found in between the teeth can still be prone to decay, especially if you do not floss.
Fluoride varnish
This is a temporary coating of very highly concentrated fluoride (about 20 times higher than the amount of fluoride found in toothpaste) that is applied to selected areas of smooth surface decay to halt the decay process.
This coating has bioactive properties (kills decay causing bacteria and increases the surface hardness of the outer layer of enamel). After 3 months, the varnish wears off due to brushing and needs to be renewed if required.
Fluoride varnish is useful for all ages but requires close monitoring of the decayed area because it is not 100% foolproof. Patients with poor oral hygiene and heavy plaque deposits tend to have aggressive decay that tends to cause cavities despite use of fluoride varnish.
ICON (resin infiltration)
This is the smooth surface equivalent of a fissure sealant. ICON is infiltration of porous (due to decay or as a result of developmental anomalies) enamel with a colourless transparent liquid plastic. This seals the porosities from bacteria and improves the appearance of white spots/striations/patches on front teeth.
ICON cannot completely cover the entire tooth to allow for access for interdental cleaning (with floss) and is usually done on selected surfaces.
These 3 methods will reduce your decay risk but none can guarantee 100% success in preventing future decay. The best way would be to employ one or more methods that are suitable with a good preventive home care regimen (use of an electric toothbrush, regular flossing and avoiding frequent consumption of sugary/starch foods and drinks).
