Zuri Barniv

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.


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.

Nov 272014

Short Answer: No

Long Answer: I’m not really sure why well-educated dentists still propagate this old-wives tale. The idea is that as the wisdom teeth erupt (or try to erupt), they will push your other teeth forward and cause them to crowd together. Some dentists use this as a reason to convince patients to have wisdom teeth removed. First let’s get the facts out of the way: This has been studied extensively and it is a myth – plain and simple.

Just one of many studies [J Am Dent Assoc. 1992 Aug;123(8):75-9]

OK, now let’s put the research away and just use some good judgement. Most people have 16 teeth on the top and 16 on the bottom. Four of those are wisdom teeth. Sometimes wisdom teeth don’t have enough room to grow out or they may be growing out at an angle (thereby getting stuck under the molars in front of them). Now how in the world can 2 teeth move 14 other teeth with long, well-establish vertical roots forward? That’s physically not possible. Imagine trying your hardest to push 14 burly rugby players huddled together all by yourself. Good luck. Also, if wisdom teeth really did push your other teeth forward, why then do the wisdom teeth stay stuck under the gums or at their obscure angle? One would think they should eventually get all those teeth out of the way and come out normally, but of course that does not happen. Lastly, many patients are shocked to notice their teeth getting crowded and they proclaim in an exasperated tone, “How come this is happening? I had my wisdom teeth taken out!”. In other words, crowding continues to happen even when there are no wisdom teeth present. This puts a big hole in the myth about wisdom teeth crowding other teeth. In fact, we see teeth crowding even when a patient has no back molars at all.

So what does cause teeth to crowd? There is a natural process that occurs every time you chew which compresses your teeth towards the front of your mouth. Teeth are naturally tipped slightly forward so every time you take a bite, they get a little shove forward. It is a very slow process but it happens a little more every day (to most people but not all). From an evolutionary standpoint, there were no dentists in ancient times. People lost teeth throughout their life. Chewing on a tooth here and tooth there is very inefficient while chewing on a grouping of teeth is much better. As long as teeth keep drifting forward, spaces between teeth were minimized as they clumped together. The end result was a happy well-fed Neanderthal.

There are very good reasons to have wisdom teeth removed and I will cover the subject in more depth in future posts. But removing them because they are crowding your teeth is not one of those reasons.

Nov 142014

Short Answer: Maybe not

Long Answer: As dentists, one of our pet peeves is patients who refuse x-rays but then expect us to tell them why they have a painful tooth or if they have any other problems. Dentists are regularly challenged by patients who refuse x-rays because they don’t want to be exposed to them and they see little value in exchange for a higher risk of cancer. Some questionable dental advice forums even tell readers that a “skilled dentist” should be able to diagnose dental problems without x-rays at all. This is utter nonsense. The only way to detect cavities when they are small and between the teeth is with x-rays. A dentist who waits until a tooth hurts or a cavity is so large it can be seen without x-rays would be acting too late. By that point, far more expensive and complicated treatment would be necessary. Many of those treatments would require additional x-rays to complete and there would be an increased chance some of the affected teeth would be lost earlier in life. There is little disputing the enormous power of dental x-rays. As I tell my patients, upwards of 75% of my diagnosis comes from looking at them and only 25% comes from symptoms and a thorough clinical exam.

Fear of dental x-rays is a valid concern, for as everyone knows, x-rays can lead to cancer. But what most patients don’t realize is that the average dose needed for dental x-rays is very small compared to what they are envisioning. This is especially true when considering digital x-rays. Many are also not aware of how much radiation they are exposed to naturally 24 hours a day. There is radiation coming from outer space (cosmic radiation), from the ground and in the air we breathe. Radon gas, found at higher doses in some homes, is one of the leading causes of lung cancer, yet few people are very aware of it. Just a seven hour flight across the country exposes you to 0.03 mSv of radiation (Note: Dose of radiation is commonly measured in millisievert (mSv)). On average, when taking into account all this “natural” radiation, you and I are exposed to about 3.5 mSv per year.  If you went to the hospital and received a lower gastrointestinal tract x-ray, you would be exposed to a little over 4 mSv. By comparison, a set of four bitewing films in a dental office would expose you to 0.005 mSv, which is about HALF of a one-day-equivalent of “natural” background radiation. The amount is truly miniscule, so it’s important to keep things in perspective.

Nevertheless, we must not forget that all ionizing radiation is, indeed, harmful. Therefore, all x-rays should be kept to the bare minimum necessary. This is why I do object to cart blanc recommendations for annual or bi-annual x-rays when they are prescribed without regard for the patient’s specific situation. Unfortunately, most dentists pay no regard to the American Dental Association and Food and Drug Administration guidelines which recommend far fewer and less frequent x-rays than are usually prescribed. In their most recent guidelines, it was recommended to take four individual x-rays of back teeth (bitewing films) every two to three years, so long as the patient had no cavities and was not at an increased risk of developing them. For patients that have cavities and are susceptible to other dental problems, their recommendation is to take x-rays every six to eighteen months. Yet most dentists take updating x-rays on everyone every twelve months regardless of the circumstances. I believe this is largely a product of most dental insurance plans which pay for diagnostic x-rays once a year.

I have patients in my practice that are in their 30’s, they have never had a cavity, keep their mouth impeccably clean, use no medications and have no medical problems associated with increased dental problems (like diabetes or blood pressure medications). I believe it is unnecessary to prescribe annual x-rays for these patients, because the risk of radiation outweighs the extremely miniscule chance a dental problem will be discovered. The American Dental Association agrees with that perspective. For these patients I feel perfectly comfortable extending their x-ray frequency to every two or three years. Even average patients who have completed all their recommended dental treatment and have a track record of dental stability can easily extend their x-ray frequency to every 18 months. The patients I insist on seeing annual x-rays for are those with, among other things, previously diagnosed but untreated tooth decay, a history of recurring problems, many large/deep fillings, teeth that had root canals recently, changes in medications/medical situation, those with poor oral hygiene and those with active gum disease. When these patients insist on not having any x-rays, it puts me in a difficult situation. We as dentists are responsible for the patient’s oral health but want to honor their request. Some dentists have dealt with the problem by having affected patients sign a release form stating they don’t hold the dentist liable for not taking x-rays. This would likely not test well in court, because a medical provider cannot be released from practicing the Standard of Care (which is to take x-rays at least sometimes) by a patient. Nevertheless, the issue of x-rays remains a point of friction for many dentists and their patients.

As for children, my recommendation for frequency also falls in line with the American Dental Association recommendations. The frequency depends on whether or not the dentist can see between the teeth visually and whether the child has an increased risk or a history of cavities. In children, decay develops more quickly because baby teeth are softer and smaller than adult teeth. This makes it more important to catch cavities early.


If a dentist recommends annual x-rays and you are concerned, ask what it is about your specific dental situation that leads to the recommendation. If the answer is something like, “Because it is our policy to take x-rays on everyone every year.”, then this would be a legitimate reason for further inquiry. If, on the other hand, the answer is, “Because you have several teeth we think have cavities, we’re not sure your gum disease is under control and we are still working out the kinks in your home care routine.”, this would be far more reasonable and well-thought-out on the part of the dentist.

It is important to remember that if indicated, refusing x-rays will increase your risk of enduring more expensive and potentially painful problems later on. Like most medical problems, early detection of dental disease is easiest to treat. While reducing exposure to x-rays is a legitimate concern, it should also be a concern that undiagnosed dental disease will affect your health and the health of your mouth. The key is to question whether your prescribed frequency is customized for your specific situation or not.

Nov 092014

Short answer: Mostly no, but keep in mind there are dentists who recommend a root canal even when the justification is dubious.

Long answer: There are many different reasons teeth need root canals but the most common reason is that the tissues inside the nerve canals die (become necrotic). Typically this can happen due to trauma (your tooth was injured by a fall or even from the trauma of a dental drill during routine dental work), a deep cavity infected it, the tooth has severe gum disease which spread to the nerve tissues or the dentist sees signs the tooth is melting from the inside (a very rare event called “internal resorption”). Once a tooth’s nerve begins to die, there are often symptoms associated with it and this is commonly known as a “toothache”. Occasionally, there are no symptoms at all and the dentist simply finds an issue detected only in an x-ray. If any of these legitimate reasons are present, it is a good idea to have a root canal done. Some people have cited health reasons to NOT have a root canal done even when one is justified (like severe pain). They believe root canals can poison your body or leave some infected tissue behind which can lead to long-term medical problems. Suffice it to say that I believe a properly done root canal is a medically sound procedure which is beneficial to you when it is reasonably necessary, with the only alternative being the removal of the affected tooth. I say “reasonably necessary”, because there are dentists who believe in doing root canals prophylactically under certain circumstances.

“Prophylactic” root canals are those root canals done to facilitate some other dental procedure. For example, some dentists believe that when a tooth needs a dental crown (the covering placed over a tooth), it should always get a root canal first. Proponents of this believe doing a root canal is justified for a variety of reasons. Sometimes it is so a retaining post can be placed deep inside the tooth to better hold up the crown ultimately glued to it. Some dentists also believe it is best to do a root canal before any crown is done on a tooth or even just to make an otherwise sensitive tooth not sensitive anymore. There are rare cases where these situations are justified, but I do think they are very rare. I do not believe a tooth should have a root canal procedure unless it is absolutely indicated (pain, obvious x-ray signs, a cavity is followed into the nerve by a dentist doing a filling, etc.) and no other alternatives are available besides removing the tooth. This is why I would never recommend a root canal to a patient simply so that I can place a post inside it and I would certainly not recommend it prophylactically as an adjunct to a dental crown. Each case is different, but I have not discovered any justification for these types of latter root canals and a second opinion is advisable if your dentist cites these reasons as justification. The best rule of thumb is if your tooth has absolutely no symptoms and your dentist recommends a root canal, ask lots of questions. If you are not satisfied with the answers or your instincts are nagging you, get a second opinion. Remember that a lack of symptoms does not mean a lack of problems, so don’t assume your dentist is lying to you just because you can’t feel anything.

Nov 042014

Short Answer: No

Long answer: There are many reasons not to replace fillings that are intact and functioning properly. For starters, there is some risk to every dental procedure. Every time a filling is removed, there is a risk the tooth will fracture, will become sensitive or have other long-term issues. Secondly, metal fillings have been time-tested and proven to be reliable extremely long-lasting solutions to cavities. Placing white fillings is a very technique sensitive procedure which, if done incorrectly, can show signs of failure after just a few months. In other words, if a white filling is not placed with a high level of skill, you might find yourself needing to replace it five times in the time you would have replaced one metal filling. Finally, why should you or your insurance bear the expense of this procedure if there is no clinical reason for it? This would be like paying to upgrade your computer’s software only to get a new version with a nicer interface but which is not necessarily better and could even be worse than the older version!

As I see it, there are only a few reasons to replace metal fillings. One might be for cosmetic reasons, as white fillings look more natural than the metal ones. Although I discourage patients from replacing their metal fillings for this reason and I always discuss the risks of doing so, it is a matter of personal choice. Also, some patients are concerned with mercury vapor and mercury products emanating from their metal fillings. This is a very contentious issue among dentists and the public. Some dentists believe mercury fillings are bad and others think they are perfectly safe. Some in the public have claimed that moments after they had their metal fillings removed, they were cured of chronic illnesses like asthma and multiple sclerosis. I always find those claims peculiar because what is known is there is an elevated concentration of mercury vapor emanating from metal fillings during the process of removing them. Most people have elevated mercury levels in their blood after having these fillings removed. So if one were cured of multiple sclerosis moments after having their metal fillings removed, then perhaps mercury vapor should be studied as a cure! Or perhaps what is much more likely is that there is a strong psychological component to the process and this cannot be underestimated.

In all fairness, we need to give the other side of the coin a fair shake. Although the position of the American Dental Association is that mercury fillings are safe, it is impossible to prove such a statement. After all, it is not possible to prove a negative. Mercury is a known toxin and it would be prudent to minimize exposure to it. As such, I have chosen not use mercury based filling materials in my office. But this is a far cry from actually recommending someone replace their metal fillings because of the mercury issue. In fact, the American Dental Association has taken the position that any dentist who does this is behaving unethically.

I believe in a more level-headed and logical approach: If there are sound reasons to replace a filling (it is cracked, there is new decay around it, etc), then replacing said filling with a non-mercury alternative minimizes exposure to any mercury. That seems to be a good compromise by my standards. But this is only reasonable if the white filling replacing it is done using the best techniques and with the utmost care (see discussion on proper technique in the introduction of this site).

Oct 302014

Short answer: At least 30 minutes and typically 45-60 minutes.

Long answer: During a routine cleaning, the dentist or hygienist needs to review any changes in your health, they need to evaluate the health of your teeth and gums and then counsel you on any improvements that should be focused on at home. Sometimes, the evaluation of your gums requires that they measure the gum pockets to look for signs of inflammation and bone loss. They then need to clean off any accumulations on your teeth, floss them and remove any stains. For most people, this takes a half hour at minimum and more likely longer. Some offices have special assistants that help the hygienist and this expedites the process. During a simple (routine) cleaning, only the surfaces above the gum (supracrestal) are cleaned. That’s why a simple cleaning is usually a comfortable procedure and doesn’t take much time to complete. Some people, in fact, have so little accumulation on their teeth that it is actually possible to do a thorough job in less than 30 minutes. But these are precisely the patients who are good candidates for less frequent cleanings. See, “Do I need a cleaning every six months?”. One other exception is patients with far fewer natural teeth than normal. If someone has half the normal set, then it would clearly take less time to clean them yet a decreased frequency may not be the best option. Also, it’s important to remember that a regular cleaning is very different than a “deep cleaning” and this is a topic that will be covered in an upcoming blog entry.

If you feel your cleaning is too short, inquire as to why that is. Consider asking for a less frequent cleaning if the answer is simply, “you don’t have much to clean.”. A thorough cleaning will remove the vast majority of stains and all hard tartar (calculus) on the surfaces of the teeth. In most people, this process takes more than 30 minutes to complete and usually 45 minutes or more.

Oct 182014

Short answer: No, in most cases.

Long answer: Unlike metal fillings (the conventional kind also called mercury or amalgam fillings), white composite fillings are very technique sensitive. In order to be done properly, a white filling requires several steps that have to be done in the right order and with the correct timing. In between those steps, if the tooth is dried out too much, or one of the chemicals stays too long on the tooth, the result could be a very sensitive tooth long after the procedure is completed.

As always, there are exceptional cases and circumstances. Sometimes teeth with very deep cavities can be persistently sensitive for a few days or even a week or two, but this is not a rule and would still be uncommon. Also, some people are so exquisitely sensitive that they perceive pain even from the slightest stimulation. It is conceivable that these people experience pain more intensely and of longer duration after routine dental work than the average person.

If you’ve had several fillings done and they are painful for weeks or months afterward, this is not a typical response. I would encourage you to discuss the situation with your dentist or to seek a second opinion.

Oct 162014

Short Answer: No

Long Answer: Most dentists will argue that a checkup every year is a wise thing to do and I would be hard pressed to disagree. But if a patient requested an exam every 18 months or even 24 months, I would not necessarily object so long as some criteria were met: they had a history of few or no cavities, they maintained good oral health and they did not start new prescription medications or have significant health changes. We are concerned with prescription medications because many of them cause xerostomia (dry mouth). A dry mouth doesn’t have the normal saliva flow which would otherwise buffer acids and wash away bacteria that cause decay. If a patient had some cavities every few years, had many teeth with fillings and other dental work or had a few health problems (this describes the majority of people) then an annual exam is appropriate. There has been some research looking for scientific evidence that frequent checkups by a dentist leads to fewer cavities. Recent reviews of these studies have shown that there is no specific recall frequency which is best for everyone. In fact, there is plenty of evidence to support the position that an exam frequency every 2 years does not result in a person having more cavities in the long run. And since dental decay takes anywhere from two to eight years to progress into an irreversible form, I can find little harm in waiting one to two years between dental exams. There are very rare situations when a person is at high risk of developing dental problems and they would need to be examined more frequently. But these situations are so rare that for the sake of answering the question, a checkup more frequently than once a year for the average person is not necessary.

[A Systematic Review of Dental Recall Intervals and Incidence of Dental Caries; The Journal of the American Dental Association May 2010 vol. 141 no. 5 527-539] [IS THERE A SCIENTIFIC BASIS FOR SIX-MONTHLY DENTAL EXAMINATIONS? The Lancet, Volume 310, Issue 8035, Pages 442 – 444, 27 August 1977 doi:10.1016/S0140-6736(77)90620-1 ]