The Trouble With Dentistry As Seen By A Human Doctor

I came across an article on Dr. Joseph Mercola’s website.  He is a functional medicine physician who is prolific in content helping humans understand their health.  I discovered him when listening to many podcasts as I search for information that will help our horses live better.  This is where the research is being done and the ideas formulated in human nutrition that directly connect to health.  Little if any unbiased research in nutrition in horses regarding their overall health is being done.

The title of his blog is “The Trouble With Dentistry” and clicking this link will open his post in a new tab for you to read.  It may be worth a read just for your own sake, but I saw a direct correlation with what is now prevalent in equine dentistry.  The article covers preventive maintenance and the addressing of dental issues,

Basically, Dr. Mercola rips apart human dentistry as a profession trying to fix things without proof of the efficacy or regard to the overall health of the mouth.  From the post:

As noted in recent article in The Atlantic (cited), “[W]hat limited data we have don’t clearly indicate whether it’s better to repair a root-canaled tooth with a crown or a filling.” Derek Richards, director of the Centre for Evidence-Based Dentistry at the University of Dundee, commented on the gaping hole of evidence in the field of dentistry.  “The body of evidence for dentistry is disappointing. Dentists tend to want to treat or intervene. They are more akin to surgeons than they are to physicians. We suffer a little from that. Everybody keeps fiddling with stuff, trying out the newest thing, but they don’t test them properly in a good-quality trial.”

I find a similar situation in the care of teeth and the whole oral cavity in horses.  Just place the word “equine” in front of the word “dentistry” made in the above quote.  The leaders in the veterinary community focus on fixing things they observe with their eyes during the very detailed exam using high-intensity lights, mirrors, endoscopy and a well-medicated, well-immobilized horse.  Rarely do I find comments in their literature that relates what they find to the overall condition of the horse.

For example, what are the ramifications of administering the medications they use in their routine dentistry?  Texas A&M vet school presented a finding at the AAEP meeting 2 years ago that showed that 1 dose of Previcox (a common pain medication in horses) killed a whole group of the 700 normal bacteria species found every day in the mouth.  Yes, there are about 700 families of bacteria that live in the mouth of the horse.  There are trillions of bacteria in, on and around you and your horse.  In layman’s terms, in a neighborhood of about 700 individual families which makes up the thousands living in a town, a whole family was wiped out including aunts, uncles, moms, dads and children.  One dose did that – but with no outward signs of a problem.  The question to ask is what effects occur on the health of the teeth and gums when horses are automatically sedated?  We all know the effect of bute (phenylbutazone) on the lining of the cecum and colon but what about sedation on the oral health of the mouth?  We are all learning about the microbiota of the gut and that any disorganization of this (dysbiosis) leads to ulcer formation in humans.  So what does the sedative do and is the risk worth the benefit?

Tooth Fractures And Nutrition

In Dr. Marcola’s article, he cites data that suggest that dental decay starts with nutrition.

“Excess dietary sugar is the most significant factor driving dental decay. (cited)”

I find it interesting that when I went to vet school in 1980 there was no mention of tooth fractures in horses.  I cannot believe that this was an oversight.  I have several vet texts from the 1800s and there is no mention of tooth fractures.  As most of you know by now, if you have been following my blogs, I will probably blame sugar as the cause of this in horses too.

While fractures can occur in any cheek tooth in the horse, they are most common in the 4th tooth both upper and lower (the 9’s).  I have noticed a swale (a depression or low spot) in the chewing surface of the lower cheek teeth and the outside surface of the upper cheek teeth with the 4th cheek tooth being centered in this swale.  My assumption is that this is the location where the tongue moves across the chewing surface to access the space between the cheek and the teeth.  This movement is constant in positioning food and in cleaning the mouth.  This movement creates premature wear on the surface of the pulp chambers allowing access for bacteria.  Unfortunately, the addition of high acid sugars in grains disrupts the normal bacteria in the mouth and like in humans, the opportunistic bad bacteria penetrate the worn pulp chambers.  With time, the decay worsens and impacted food drives further into the tooth creating a wedge that splits the tooth.

While there is no accurate data here, I can hypothesize that in horses not fed extra sugar there would be no decay and fractures.  I have stated in another blog that the advent of another tooth disease, EOTRH, was not until grain became commonly given to horses.  To quote Dr. Mercola again,

“As Meinig discussed in our interview, the only scientifically-proven way to prevent tooth decay is through nutrition. He related how in Price’s travels he found 14 cultural pockets of natives who had no access to “civilization” and ate no refined foods.  While their diets varied, they all ate whole, unrefined foods. Without access to tooth brushes, floss, fluoridated water or toothpaste, each group were almost all 100% free of caries.”

In Dr. Steven R Gundry’s book “The Plant Paradox,” he discusses a 1932 study where oatmeal was linked to the cause of dental caries in children.  Removing oatmeal from their diets reversed decay in many and prevented further decay in most.

The Health Of The Mouth And The Body Is Connected

Quoting again from Dr. Mercola in his article,

“The delicate balance of bacteria in your mouth is as important to your health as your gut microbiome.”

More reasons to go grain free in your horses.  But should you trust the dental findings from the dental expert looking at your horse’s teeth?  As the article says, most people don’t get a second opinion in dentistry like they do in surgery or medicine.  It is a habit we have carried over to our horses.

With the emergence of several dental conditions not discussed in the veterinary texts before 1980, I can only wonder about the contribution continually feeding sugar (grain, grain byproducts, treats, carrots, apples, etc) has had on the health of the teeth.  Another way of looking at this is to ask how horses managed to survive for millions of years if their teeth decayed and gum disease was common.

It is exciting to open the mouth of the horse and discover disease – at least for the veterinarian.  But after looking at 70,000 horse mouths I am seeing that horses have developed a very robust mouth.  But it doesn’t mean we can abuse the normal bacteria nor can we ignore the delicate balance there between the mouth and the whole horse.  From this perspective, I disagree with my colleagues who jump at the opportunity to extract a tooth or do advanced dental procedures.  What is needed is well-done routine maintenance without automatic medication removing the daily pain from sharp edges that restrict the movement of the tongue and the distribution of health-supporting saliva.  This plus removing the acids of the daily feeding of grain and other sugars will keep the mouth of the horse in great shape for life.

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  1. Bad sugar effects aside for a moment, do you know if feeding whole oats to feral or unhandled horses help with sharp points? I have an abused horse who may not ever trust humans again and this is post excellent mustang trainer who did what he could do in a couple of months. I read a New Zealander article that recommended the whole oats in minimal quantities as part of forage diet to help prevent sharps forming. Thanks so much for your generous informative website.

    1. Thanks Linda for finding me and reading and commenting. As far as I can tell sharp points form from the wearing away of the occlusal surface with the formation of an edge where wear doesn’t occur. Then the tongue strops the edge (look up the word) into a razor sharp edge. This is what is filed off in floating.

      How quickly this forms is determined by the hardness of the teeth (in general younger horses have softer teeth) AND how many times they chew (more chewing in grazing horses – 40,000 chews per day – than stabled horses – 10,000 chews per day). Horses that don’t chew much because they are on a liquid diet (damaged esophagus, sinus fistula) rarely have sharp edges worth floating in 12 months.

      In my opinion, chewing causes tooth wear and the eventual development of sharp points. Therefore I cannot believe that feeding anything would decrease the number of chews and thus decrease the development of points. Further, oats are soft and tooth enamel is hard. Chewing oats or whole corn will not blunt the points. An even if it did, it would not leave a uniformly smooth edge but, if it chipped off the sharp point, it would leave more sharp edges where the chip occurred.

      In a nutshell, I do not believe that feeding ANYTHING to horses will smooth or decrease the sharp points. I have not seen in in the 37 years of floating teeth. The only thing I have seen is horses that do not chew (liquid diets) develop few sharp points. If you have any evidence to the contrary I would love to see it. Thanks, Doc T

  2. I agree with Doc T- nutrition is key. I need to pipe in on the human side. As a dentist who has worked in public health for over 18 years, what is most important is education about oral health: understanding why decay and periodontal disease happen so you can aquire the tools to understand and maintain your own health. Just a few key points: Sugar alters your gut and saliva. Saliva is naturally designed to cleanse the mouth. When you add too much of one thing to your diet or regimen (sugar, soda, medicine, drugs, etc.) saliva is altered therefore it can’t do what it is supposed to do. Soda contains phosphoric acid to preserve the sugar in the soda. Phosphoric acid also dissolves the calcium in your teeth, making them more susceptible to decay. Medicine or drugs? They can alter or reduce saliva (cotton mouth). Then the sugary substances sit on your teeth and do their thing if they aren’t removed. Teeth are designed to be relatively bomb proof. The minute they are compromised by decay they will never be 100% again. Fillings are designed to repair the hole created by decay. This means there is less natural tooth structure which makes the tooth vulnerable to fracture as well. I could go on but I urge you to ask questions of your dentist. We do use evidence based dentistry for many things in public health!

    1. Thanks Wendy! Nice of you to post here and link us back to our own mouth.

      Remember that the morphology of horse teeth is very different from human teeth but the materials are the same (just put together differently). The reason for this is simple. Humans chew about 2000 times a day (730,000 chews in a year) according to my dentist. Horses chew on average 25,000 times a day (750,000 chews per month and 9 million per year). Horses needed to build their teeth differently.

      This said, the basics of what Wendy says here correlate very well with horses. Texas A&M vet school showed that 1 dose of the anti inflammatory previcox wiped out a whole family of bacteria in the mouth of the horse. One dose. Add to this daily dosing of several medicines, carrots, grain and stress (shipping, showing, confining) and you can imagine the dysbiosis of the normal microbe flora of the mouth.

      I love this: “Teeth are designed to be relatively bomb proof.” So true! How did they (or ourselves) survive millions of years without help?? Thanks again, Doc T

  3. Deborah Ide
    I don’t see this as explaining why my horse Tara had two fractured teeth (the upper cheek teeth you describe on right and left sides) as she eats no grain, eats low sugar hay and no treats, etc…. a low sugar diet, and has for years. Further explanation please? Thank you!

    1. The teeth that are at the occlusal surface were formed years ago. This includes the pulp chambers. The decay that starts this process of splitting the tooth started


      she was 5 years old. Once started there appears no way to stop it.

      Pulp chamber decay is a very slow process as recent data collections will attest to. Modern vet dentist actually measure the depth of the decay in the pulp chambers and identify which chambers have decay. I don’t do this because as far as I know, there is no stopping this process once started. This includes removing grain in an adult horse such as yours. The end result is the fracturing of the tooth which no one has a plan to prevent. Heck, no one at this time has a reason for it happening other than my hypothesis here. But there was no discussion of fractured teeth in the vet text books in the 1980’s.

      Some dentist advocated cleaning the decayed pulp chambers out and filling the drilled out area with filling material used in human teeth. I went to a discussion on this in 1999. The presentation was slick and not based in science. Since that presentation, the presenter has been disgraced (he wasn’t a vet yet he was teaching at a vet school), removed from practicing in several states and sued. Further the AAEP a few years ago had a researcher that showed evidence that filling cavities in horses failed almost every time. This is why vets today do not fill decay in horse teeth. And they still don’t have a proven cause either.

      Here is another question to ponder. While I have seen every tooth in the mouth fracture, why is the 4th cheek tooth (the upper and lower 9’s on either side) the most often fractured tooth? My guess is related to the swale formation in all arcades at this area caused by the maximum movement of the tongue in cleaning the mouth.

      Finally, in my experience, fractured cheek teeth rarely have a complication once the fractured piece is removed. As with your horse, they often don’t even show a sign of a problem on the day of the visit – an incidental finding. However, removing grain from the diet must certainly help in reducing the negative effects of the starch from the grains. But remember that there is starch in pasture and hay as well so removing all sugar seems impossible. In addition, all medications will affect the microbiome of the oral cavity. Texas A&M vet school showed that 1 dose of previcox wiped out a whole family of bacteria in the mouth of normal horses.

    1. There are many theories and beliefs that have developed in equine dentistry since I started in 1983. Some have been good and some have no proof in any evidence (anecdotal or scientific). This includes some from my veterinary colleagues.

      Included myths are equilibration, incisor reduction, balancing the mouth, speculum use, automatic sedation, immobilization, lateral excursion, unnecessary tooth extraction, mapping of the oral cavity and possibly a few more I can’t think of right now. I have written extensively in my blogs ( as well as videoed my thoughts here:

      Thanks for asking about one particular style of dentistry and my apology for answering in a blanket statement, but in the last 20+ years equine dentistry has become divided into entrenched camps. It is much like discussing President Trump. You either are for or against a belief and little argument will persuade a movement away from your belief. I truly am grateful that there are so many people trying to make a difference in the oral health of horses and this includes those who think differently. They are NOT an enemy and all people getting dentistry performed are giving some relief to the chronic oral pain of horses. I just think differently about how to do it.

  4. Much of this I find to be what we discussed regarding my horse Tara after she presented with a fractured tooth last year and you eventually had to remove part of it. I know you will see her in August, but I want to say that she has not had the rest of her tooth extracted, is eating 2nd cut hay and balanced Timothy cubes as well as flax and mineral mix custom balanced to her hay, salt and vitamin E and has a shiny coat, plenty of energy, a good appetite and is is good body shape (body score around 5). She does not carry any extra body weight and is not thin–just right. Thank you.

    1. Thanks Deborah. You had been advised to extract the whole tooth but obviously so far that has not been necessary. Thank you for trusting and doing what was in her best interest. See you in Aug, Doc T

  5. I agree. Sugar is bad but phytic (spelling?) acid is the worst. I have some sugar in my diet and it hasn’t bothered my teeth too much lately but when I chew things like almonds my fillings literally fall out and it’s not due to the hardness of the food. Oats are high in this acid.
    One of my favorite books is called ” it’s all in your head” by doctor Hal Huggins.
    Doc T please also remind everyone not to have they’re older horses ( upper twenties ) teeth floated. I regret calling my new to the business of equine Dentistry young lady who took an Electric Tool to my old but extremely healthy horse’s mouth and filed too much tooth off and since that day has not been able to chew any hay at all. It has cost me a fortune to feed him because of this but he is still going strong at 33.

    1. Thanks Bobbie for this comment. It is usually not associated correctly the cause and the effect of things. In reality sugar affects the normal gut bacteria and this in turn has a bad effect on the teeth including causing further decay under a filling. A hard tree nut such as an almond my be all the pressure needed to push the microscopically loose filling away from it’s now poor bond with the tooth.

      As far as advising horse owners to not float the teeth of older horses, I can’t agree. This morning I worked on a 29 year old that needed a few sharp points smoothed and an end stage tooth removed. He then went to immediately eating normally with a purposeful chewing motion, something that had not occurred in months.

      Every older horse I float, especially for the first time, I warn the owners that they may need a few days to learn how to chew again without pain. When this occurs the owner is not surprised. Some young dentists take too much off and this will affect the chewing motion for months to years in older horses. It is the training of these dentists that needs attention and NOT the avoidance of dentistry in older horses. You just had a bad experience and for this I am sorry. I wish all young dentists knew their power inside the mouth of older horses. We teach this explicitly in our dentistry school. Help other people by letting them know that while dentistry helps all horses and especially older horses that have not been floated for a while, they need to verify the credentials of their dentist or at least help them learn about dentistry in very old horses.