The American Academy of Pediatric Dentistry recommends placing dental sealants on the first permanent molars (at around 6 years of age) and the second permanent molars (which come in around 12 years of age).
Why? --Well, basically there are a lot of studies that say placing sealants helps reduce the incidence of cavities. Does it mean you will never get cavities?--no, it still can happen, but sealants can reduce the kind of cavities that form in the pits and grooves of the back teeth, you know on the top of the tooth--you still can get them in between the teeth and on the smooth surfaces.
How long do they last?--Even with a well placed sealant I have seen cavities form in areas previously sealed. Sometimes the sealant wears off (chewing ice for instance), or sometimes just because someone is very prone to cavities. They say they last from 5 to 7 years if you take care of them--even adults can get sealants, but they seem to be most effective in the cavity prone years of youth. What is the material? Well, it's basically the same material as used in white fillings without as much filler/reinforcing material, it's a bis-GMA resin, With less filler the sealant can flow into the grooves better. Sometimes we use "flowable" composite which is kind of in between in it's characteristics.
How are they placed? Does it hurt?--I like to say it's like painting fingernails--you basically just paint it on the tooth--now that can be harder than you think as these teeth are in the back of the mouth. Most of the effort is keeping the area dry.
Do you put them on baby teeth?--you can, but generally no. The enamel in baby teeth is different microscopically, they don't seem to stay as well, but sometimes if there is lots of grooves there, so there may be a benefit to placing them. Another thing to think about is that in preschoolers, placing a sealant is just about as difficult as a small filling because little kids, well it's harder to place the sealants. It is often better to simply have regular checkups to catch things early. Also, like I said many cavities in baby teeth are in between the teeth which sealants do not prevent.
I'm going to try and make a video on this some day.
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