Apr 062015
 

Short Answer: Not necessarily

Long Answer:
When we talk about sealants, we are almost always talking about a very thin plastic-like film a qualified dental professional places over the grooves on the tops of adult teeth (the chewing surface). It is thought to work by preventing food and plaque from going deep into the crevices of the teeth where cleaning is impossible. By preventing debris from going into these grooves and crevices, cavities are less likely to form. Although it is (in my mind) debatable whether sealants prevent cavities from forming on the tops of the teeth where they are placed over the long haul, everyone agrees that they do absolutely nothing to prevent decay in between the teeth (where you would place dental floss). Cavities between the teeth are where many cavities form in children, which makes sealants useless for at least a big portion of possible cavities. Nevertheless, the overwhelming scientific literature and the opinion of most dentists is that sealants are good.  For those not interested in the minutia, suffice it to say that the typical sealant using the most popular material (composite resin) can fail over time or they can cover up problems which may be detected too late. This can lead to much more costly and painful problems in the long-term. I think the alternative, which is doing very small fillings should the child actually develop a cavity, is much more rational and less-invasive in the long term. Another alternative is a newer sealant material made of something called “glass ionomer” which I believe is much better and I recommend these. The product goes by the brand name “GC Fuji Triage”. Unfortunately, the vast, vast majority of dentists still use a “resin-based” material which I believe is far inferior and possibly harmful. Now let’s delve into some more details if you have the interest :).

 

The REALLY Long Answer:
First I will review more about what sealants are: Most back teeth (molars) on children have lots of grooves on their top surface. The first adult molar to erupt is usually at around 6 years of age and they are the first to be “sealed”. A sealant attempts to literally seal off those deep and narrow grooves on the biting surfaces of the teeth. In most cases, the “sealing” material is made of a flowable resin material not very different than what a dentist places in a tooth when doing a regular filling. From this point on, I refer to the material as a composite resin sealant (CRS). It is important to differentiate this from a glass ionomer sealant discussed towards the end, which is a very different material. The process works like this: the  tooth is cleaned off in some way (sometimes mechanically or chemically) and then the CRS (a liquid about the consistency of maple syrup) is flowed into the grooves and crevices of the tooth. A special curing light is applied which hardens the liquid into a solid. As long as the CRS doesn’t come out with normal wear and tear and the bond between the CRS and tooth remains completely intact, sugars cannot get into the grooves of the tooth. Without sugars, bacteria that cause tooth decay are cut off from their food supply and they typically go dormant (they don’t die, they just stop causing a problem temporarily). Because the sealed surface is smooth and shallow, food and liquids don’t collect as readily in the grooves and anything on the teeth is easily brushed away. The end result is that the child should have fewer cavities on the biting surfaces of their teeth. Sounds great and it is no coincidence that dentists love this procedure. After all, it is theoretically healthy for the child and the dentist makes money for each sealant placed. Insurance companies gladly pay for this procedure.
So why am I not as enthusiastic as others? I too was once a big proponent of sealants until I started noticing troubling issues occurring with them. I have many children in my practice who have impeccable oral hygiene. They brush and floss, use fluoride toothpastes and come in regularly for checkups. Many of these children had CRS placed by their last dentist when they were around 6 or 7 years old. I noted that some of the sealed teeth had a darkened shadow appearing under them and that troubled me. Healthy adolescent teeth usually have no gray or shadowy colors under their top-most biting surfaces. Close examination of the x-rays yielded little in the way of new information. Dental x-rays show decay in between teeth much better than decay on their biting surfaces where sealants are placed. Although all I had to go by was an insidious dark shadow, it was suspicious enough that I recommended removing the sealants to determine the cause. One by one, as I removed the old sealants, I was shocked by what I discovered: In all cases where I saw a dark shadow under the sealant, and with no other indication or x-ray finding, there was a massive amount of tooth decay present (a huge cavity). In some cases, the decay was so deep that the child almost needed a root canal procedure. This was extremely disturbing to find and it was not isolated to just one or two children from one family. I have witnessed these findings over and over throughout the years and on many children from the Unites States and other countries.

HOW COULD THIS BE AND WHAT DOES IT MEAN?

Consider a wooden row boat. If the hull developed a very tiny leak, you would see it immediately. A timely repair could be made and there would be no additional problems. Now imagine the same boat with the same little leak, but this boat has a thin and flimsy plastic shell wrapping around it. If the integrity of this shell was broken, a near certainty over time and real-world use, you might not notice the leak. All the while, the wooden interior would rot away from the mold and constant wetness. But from the outside the boat would look brand new. In fact, the boat could be close to completely disintegrating on the inside and capsizing, yet there would hardly be any sign of trouble. This is the inherent issue with sealants. Unless they are closely monitored and the dentist knows exactly what to look for, the slightest debonding of its edges could be enough to feed the cavity-causing bacteria without having any of the typical outwardly signs. This could spell disaster. While my own findings and experience can in no way be interpreted as scientific, they do bring up some important concerns and questions about CRS.
As for the quality of work achievable when placing a sealant on children: Some kids are wonderful to work on and they make things easy and fun. But many children are understandably anxious and have a short attention span at the dentist’s office. The strategy many dentists use when working on children is to work as fast as possible so the job gets done before the child is “done”. This may be acceptable when doing a filling on a baby tooth which will eventually fall out. But sealants are placed on permanent adult teeth. If a sealant is not placed carefully and on a very dry tooth, it will not adhere as well and will leak more readily. A leaking sealant spells trouble, as we already established. So when an experienced pediatric dentist (specialist in children dentistry) or general dentist with years of experience places a sealant, it may be done optimally. But in many states, it is perfectly acceptable for a general dentist’s assistant or hygienist to place them too. Many dental schools send out students to place sealants on low income children as a public service. There are exceptions of course, but I believe most students, dental assistants and hygienists don’t have the experience, speed and knowledge to do such a procedure without making important compromises. This is why if a parent chooses to have CRS placed on their children’s teeth, I recommend making sure the practitioner is a dentist and experienced in working with children and in placing sealants, specifically.

But if a parent needed even more reasons to be wary of sealants, I conclude the discussion with some final thoughts: Since sealants should be evaluated or x-rayed every 6-12 months to check their integrity, I can’t imagine that is worth doing for a child that is showing no problems with tooth decay. Furthermore, some sealants leech out harmful chemicals, namely BPA. Although some studies show extremely low doses or doses below FDA allowances, any exposure to BPA could pose a problem.

[Exposure to bisphenol A from bis-glycidyldimethacrylate–based dental sealants The Journal of the American Dental Association March 1, 2006 vol. 137 no. 3 353-362]

Some, like Dr. Fred von Saal, a leading expert on BPA, believe children should only receive sealants if they have a clear tendency to develop tooth decay. And since BPA is potentially more dangerous to children than to adults, the issue becomes more relevant; nevertheless, a discussion of BPA and its potential effects are beyond the scope of this blog. I simply conclude the following: If a child is taking good care of their teeth, they show no predilection for heavy consumption of sweets and have little or no tooth decay, why subject that child to potentially toxic substances, to the potential trauma of dental treatment, to the challenges of constant checks, superfluous radiation from x-rays, ongoing costs with reapplication of a sealant and to the potentially devastating effect of having a sealant hide decay that leads to much larger problems later on? I believe it makes better sense to take a more liberal approach: That is, evaluate each child for their risk of developing decay. If and when they do develop a cavity, I feel it is appropriate to remove that tiny amount of decay, properly bond in a traditional composite filling and do nothing more. The thought of covering all the grooves of a child’s teeth with a weak un-bonded material and then replacing it several times over the years seems excessive and potentially hazardous to me.
Some studies do concede that typical middle and upper class children do not need sealants as they once did; however, these same studies feel that low-income children in areas that have poor availability to dental care need sealants much more. Even in these cases, I feel that placing sealants on every low-income child is not in their best interest. Almost all studies agree that the key to the success of sealants lies in their need for constant upkeep and monitoring. But it is precisely the children in low-income communities that are the least likely to have their sealants properly monitored and that causes me pause. If a sealant is placed on a tooth and that sealant leaks, the ensuing cavity might be detected very late or not at all. One might argue that the child would have gotten the cavity anyways, but it happened later in life than it would have otherwise. I argue that if the sealant leaked and the child did develop a cavity, that cavity would likely develop faster and with less chance of being detected. After all, this specific population is under-served and their sealants are not regularly monitored. Have they been done a favor or in actuality, harmed? Perhaps these questions will be better studied over time and new ideas and conclusions will be drawn. But for the time being, assuming your child is getting checked regularly and has not been told they are at a higher risk for developing new cavities, I am against placing sealants on their teeth with one exception:
There is an alternate sealant material which I discussed at the beginning of this post called glass ionomer. It is not a CRS and does not use the typical weak flowable resin material. It contains no BPA or BPS. Unlike resin materials, it sticks better in slightly moist environments and doesn’t suffer from many of the inherent issues typical sealants have. To my knowledge, there is only one manufacturer of this type of sealant. The product is called “GC Fuji Triage“. I have yet to find any fault with using this very specific material as a sealant except that they fall out more readily than CRS. That makes it a little less ideal but I would take a less retentive sealant over one that stays in place but leaks any day! If your dentist tells you this material (GC Fuji Triage) is  being used to do your children’s sealants, then I would be comfortable with that. I would continue to decline CRS in almost every other case I can think of. I would also especially encourage dental schools and other programs prodding along inexperienced people placing sealants to put away CRS materials and use glass ionomer instead.

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  2 Responses to “Q: Are dental sealants good for my kid’s teeth?”

  1. I had sealants put on my kid’s teeth today. When we got home my son bit a chip and a piece of the sealant came off in his mouth. I am regretting putting on the sealants. Can I take my kids to a dentist to remove the sealants? Is it safe to remove them? How would they be removed?

    • You can and it is safe to remove them but a drill may be needed to get them off. Why don’t you consider having the dentist repair the broken sealant and if it chips or breaks again, then maybe having them all removed is thew way to go…
      Dr. Barniv

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