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Tooth Abscess
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Pauline Moore
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Joined: Fri Mar 23rd, 2007
Location: Crows Nest, Australia
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 Posted: Tue Mar 3rd, 2009 12:28 am
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Dear Dr Deb

A client's horse, a 9yr old warmblood, has just had a second tooth, an incisor, removed due to an abscess.  A molar was removed for the same reason less than a year ago.  The vet/dentist concerned reports that he is being confronted with having to pull abscessing teeth in young horses regularly and is blaming the overuse of power tools and consequent removal of too much tooth by previous dental practitioners.  My client has been told her  9yr old has the teeth of a 15yr old horse.

I've gone back over all my dental notes from your dissection courses but cannot make any sense of these claims that the dentist is finding 'pulp exposures' in all these young horses.  I've looked at the diagrams showing how the dentine, cementum and enamel wear down to give a rough chewing surface but cannot see how simple wearing down of teeth by either natural chewing or any form of dentistry tool would expose pulp in even a 15yr old horse.

My questions are:

Is it possible for a tooth abscess to be caused by too much tooth being taken down by a dentist?

Is it possible for a tooth abscess to be caused by the heat generated by a power tool?

What other likely causes could be responsible for a large number of young horses losing teeth to abscesses?

Best wishes - Pauline

Tasha
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Joined: Thu Mar 22nd, 2007
Location: South Island, New Zealand
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 Posted: Tue Mar 3rd, 2009 10:44 am
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I know I've read a paper that pointed to the death of teeth through overheating due to power tools. Perhaps dead teeth lead to abscesses? If I remember correctly the authors came up with the recommendation that a power tool should not be in contact with a tooth more than 30 seconds, any more than that risks killing the tooth and the tooth should be given enough time to cool down again if further work needs to be done. I'll try and track it down though I wouldn't be surprised if Dr Deb has it at her finger tips somewhere.

In NZ I have heard that some vets aren't particularly happy with what is being done by some lay dentists who are trained in an Australian school to use power tools for horse dentistry - too much tooth being taken away (especially the incisors) or the angles of the teeth being changed too drastically. At least that is the gossip.

For the last three/four years I've used a vet who trained in equine dentistry in Canada and has passed an Australasian veterinary exam in equine dentistry, he uses a specially designed power tool for equine dentistry and while he has picked up some interesting problems, there has never been a case of a tooth abscess in any of my ponies or in any other horses he treats down my way.

So perhaps it is not a problem that powertools are being used but that powertools are being used badly?

Last edited on Tue Mar 3rd, 2009 10:50 am by Tasha

Tasha
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Joined: Thu Mar 22nd, 2007
Location: South Island, New Zealand
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 Posted: Tue Mar 3rd, 2009 07:17 pm
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I've found a couple of citations which seem familiar but it has been 2-3 years since I read the article and unfortunately I don't have access to the full journals anymore, doing distance learning through Massey definitely had some advantages. I found these citations in Pubmed.

J Am Vet Med Assoc. 2004 Apr 1;224(7):1128-32.

In vitro study of heat production during power reduction of equine mandibular
teeth.

Allen ML, Baker GJ, Freeman DE, Holmes KR, Marretta SM, Scoggins RD, Constable P.

Firethorn Equine Services, 5701 Lancaster-Circleville Rd, Lancaster, OH 43130,
USA.

OBJECTIVE: To measure the amount of heat generated during 3 methods of equine
dental reduction with power instruments. DESIGN: In vitro study. SAMPLE
POPULATION: 30 premolar and molar teeth removed from mandibles of 8 equine heads
collected at an abbatoir. PROCEDURE: 38-gauge copper-constantan thermocouples
were inserted into the lingual side of each tooth 15 mm (proximal) and 25 mm
(distal) from the occlusal surface, at a depth of 5 mm, which placed the tip
close to the pulp chamber. Group-NC1 (n = 10) teeth were ground for 1 minute
without coolant, group-NC2 (10) teeth were ground for 2 minutes without coolant,
and group-C2 (10) teeth were ground for 2 minutes with water for coolant.
RESULTS: Mean temperature increase was 1.2 degrees C at the distal thermocouple
and 6.6 degrees C at the proximal thermocouple for group-NC1 teeth, 4.1 degrees C
at the distal thermocouple and 24.3 degrees C at the proximal thermocouple for
group-NC2 teeth, and 0.8 degrees C at the distal thermocouple and -0.1 degrees C
at the proximal thermocouple for group-C2 teeth. CONCLUSIONS AND CLINICAL
RELEVANCE: In general, an increase of 5 degrees C in human teeth is considered
the maximum increase before there is permanent damage to tooth pulp. In group-NC2
teeth, temperature increased above this limit by several degrees, whereas in
group-C2 teeth, there was little or no temperature increase. Our results suggest
that major reduction of equine teeth by use of power instruments causes thermal
changes that may cause irreversible pulp damage unless water cooling is used.


PMID: 15074859 [PubMed - indexed for MEDLINE]

Aust Vet J. 2005 Jan-Feb;83(1-2):75-7.

Temperature changes in dental pulp associated with use of power grinding
equipment on equine teeth.

Wilson GJ, Walsh LJ.

School of Veterinary Science, University of Queensland, Queensland 4072.

OBJECTIVE: To quantify the temperature changes in the dental pulp associated with
equine dental procedures using power grinding equipment. DESIGN: A matrix
experimental design with replication on the same sample was followed to allow the
following independent variables to be assessed: horse age (young or old), tooth
type (premolar or molar), powered grinding instrument (rotating disc or die
grinder), grinding time (15 or 20 seconds) and the presence or absence of water
coolant. PROCEDURE: Sound premolar and molar teeth from a 6-year-old horse and a
15-year-old horse, which had been removed postmortem, were sectioned parallel to
the occlusal plane to allow placement of a miniature thermocouple at the level of
the dental pulp. The maximum temperature increase, the time taken to reach this
maximum and the cooling time were measured (n=10 in each study). The teeth were
placed in a vice and the instrument used on the tooth as per clinical situation.
RESULTS: Significant differences were recorded for horse age (P < 0.001),
instrument type (P < 0.001), grinding time (P < 0.001) and presence or absence of
coolant (P < 0.001). There was no significant difference for tooth type.
CONCLUSION: Thermal insult to the dental pulp from the use of power instruments
poses a significant risk to the tooth. This risk can be reduced or eliminated by
appropriate selection of treatment time and by the use of water irrigation as a
coolant. The increased dentine thickness in older horses appears to mitigate
against thermal injury from frictional heat.


PMID: 15971824 [PubMed - indexed for MEDLINE]

Pauline Moore
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Joined: Fri Mar 23rd, 2007
Location: Crows Nest, Australia
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 Posted: Wed Mar 4th, 2009 04:56 am
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Dr Deb - To add to my confusion, my client sent through the following extract from a dental book which appears to indicate dentine is continually being replaced at the occlusal surface - somehow I had visualized that dentine does not cover the chewing surface as the different materials with varying hardness are worn down at varying rates, hence the rough grinding surface.  Now I have no idea about anything.

Equine Dentistry Second Edition Edited by Gordon J Baker and Jack Easley  P99
“Being hypsodont, equine teeth have a prolonged eruption throughout most of their life. This is an evolutionary adaptation to compensate for wear at the tooth’s occlusal surface (at a rate of approx 2-3mm per year) due to the prolonged mastication (up to 20 hours per day) of forage which may contain abrasive silicates of phytoliths. To avoid pulpal exposure on the occlusal surface, dentine is continually laid down by odontoblasts throughout the life of the tooth. Excessive attrition of dentine with resultant pulpar exposure has been proposed as a route of infection into equine apical tissues. When dental attrition exceeds the rate of secondary dentine deposition, the pulp will eventually become exposed. The rate of dentine formation is dependent on the health of the layer of odontoblasts present at the periphery of the pulp. If this layer becomes compromised, either directly (eg from trauma or from thermal damage during dental treatments), or indirectly (e.g. from decreased or total loss of vascular supply) the resultant decrease dentine production may be insufficient to prevent pulpar exposure, the outcome is dependent on the tooth’s ability to withstand prolonged bacterial invasion”.


I know of no-one other than yourself, Dr Deb, who can explain the truth of what is really happening with these horses - your help is very much needed and appreciated.
Best wishes - Pauline


 

DrDeb
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 Posted: Wed Mar 4th, 2009 09:23 pm
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Pauline, it's not like I wouldn't have wanted to answer this. But the question here requires a careful and complete answer, and it had to wait until I had several hours to compose.

The key to the solution to your quandary lies in the quotation from Easley's textbook. Easley is the leading veterinary researcher in equine dentistry, and his book gives good information.

You are telling me through your last post that you don't understand the differences between brachydont (low-crowned) teeth such as those we humans have, or that pigs or dogs have, vs. hypsodont (high-crowned) teeth such as horses, cattle, deer, and antelopes have. If you want an excellent picture, go to your copy of Gobaux and Barrier -- the classic illustration -- note the fine dotted lines marking the length of the incisors and the usual relationship of the occlusal "table" to the pulp cavity at different ages. With high-crowned teeth, just as Easley notes, the teeth continue to erupt through the gums for a longer time than that which is merely required to initially erupt the tooth and bring it up to a level where it comes into occlusion with its mate from the opposing jaw. And this is due to the fact that grass is gritty and abrasive, both from dust which is commonly on the outside of the blades, but also to glassy phytoliths which are part of the internal structure of the blade.

The lifespan of an animal in nature is limited by numerous factors, such as whether it can get enough food and water, disease, injury, and predation. But if the animal has a good environment and escapes disease, injury, and predation, then its lifespan will ultimately be limited by the durability of its teeth. In other words, the teeth are the weakest part of a good overall system. So horses and other animals that eat grass have evolved high-crowned teeth as a way of counteracting the tendency of their food to wear their teeth down to the gums -- and specific to your initial question, the mechanism also prevents premature exposure of the pulp cavity through providing a way for dentine to continue to be laid down at a rate that hopefully exceeds the rate of "attrition", which means tooth wear.

Now, it is not really possible here to go over the whole story of the development of teeth from embryo to birth and thence to old age. Suffice it to be said that there is a layer of cells which surrounds the pulp cavity (the odontoblasts) which have the capability to lay down dentine. If these cells are destroyed, they die, leaving the animal with no way to lay down new dentine. So much says Easley also.

Now we turn to the controversy concerning whether incisor reductions should be performed. There are no grounds in fact for the claim that incisor reductions of the appropriate kind should not be performed. As I said, the key to this lies in the same information quoted from Easley: under normal circumstances, when the odontoblast layer is healthy, the horse will lay down dentine at a rate that equals or exceeds the rate of tooth wear.

The question, then, must be: what is the rate of tooth wear in the individual domestic horse, and why were tooth reductions (cutting off excess incisor length) suggested in the first place?

All of the horse's teeth are hypsodont -- both the cheek batteries, as well as the incisor batteries. And when a horse grazes in the natural manner, he has the opportunity -- indeed the necessity -- of using all of his teeth. To graze, the horse uses his incisor teeth to grasp a bunch of blades. Firmly gripping the blades, he then somewhat sharply moves his head either rearward or obliquely side-to-rear, which has the effect of tearing off the blades. (A side note here: we have one dentistry instructor here in the U.S., a veterinarian, who teaches that the horse uses a 'scissoring action' to bite off grass blades. This is completely incorrect; the horse with a normal mouth never, under any circumstances, rubs the occluded incisors together from side to side; there is no 'scissoring' action at any time. However, there are many horses that have abnormal mouths whose incisors do rub together, coming into contact before the jaws are fully closed and centered).

What happens, however, when we bring the horse into the domestic environment is that, to greater or lesser extent, he is prevented from filling his belly by means of grazing. The domestic horse, to whatever extent he is fed hay and grain or pellets, bagged feed, etc., and to whatever extent he is held off pasture, will fail to that extent to obtain wear upon the incisor teeth. For the ONLY time the incisor teeth experience wear in the horse with a normal mouth is in the actual act of tearing off the upwardly-growing grass blades. Horses that are eating hay do not wear their incisor teeth appreciably.

What this results in, over time obviously, is the failure of the incisor teeth to shorten -- to wear down as an eraser wears down as it is rubbed -- as they were meant to. Incisors that do not receive wear still have active odontoblast layers, and they still have active cell layers external to the tooth as well, that act to push or "extrude" the tooth out of the socket every single day. The amount per day is miniscule but is pre-set to match the "expected" wear. (Note that at the opposite end of the spectrum -- much less common but as Easley mentions, possible -- you could have a horse on such extraordinarily gritty food that no amount of activity of the odontoblasts can keep up. Such an animal will then have premature exposure of the pulp cavities). So you see by both these examples that the whole thing is a question of balancing the rate of wear against the rate of development and/or extrusion from the socket.

When we have the common domestication scenario, that the horse's incisors are experiencing a lower-than-expected rate of wear, the result over time will be that the incisor teeth will accumulate length. They will be accumulating length, while at the same time the cheek batteries will be receiving normal rates of wear (because the cheek teeth occlude with every chewing stroke). I say the cheek teeth occlude -- but if the incisors are not reduced by SOMETHING, then eventually they will accumulate enough length that they will begin prying the jaws open from the front. In other words, the incisor teeth are going to come into contact (a) from side to side and (b) too soon in the chewing stroke, so that when the incisors are in contact, the cheek teeth are prevented from coming into contact -- the jaws are HELD OPEN by the over-long incisors. You see: in the normal condition, the horse is the ONLY grass-eating animal whose incisor teeth are designed to come into occlusion bluntly, across a broad surface, at such a height that when the incisors are in contact, the cheek teeth are within a credit-card thickness of being in contact, too (the "credit card space" allows for the thickness of the bolus; but it's OK in some individuals, or for temporary periods, for there not even to be this much space).

Now, if the situation becomes that your horse's incisors have accumulated excess length, so that he cannot close the cheek teeth, then one or more of the following MUST occur:

(1) He will begin suffering repeated "impactive" type colics, due to inability to properly reduce the bolus, i.e. he is swallowing particles longer than 1/2" (a horse with a normal chewing stroke reduces all particles to less than 1/8", the majority being the size of cornmeal particles or coarse grains of sand).

(2) He will increase his efforts to chew on his favorite side. All horses have a favorite side, but the degree to which they favor that side is not enough to cause the difference to show up for many years. But horses that are desperate will try harder, and if this is the strategy for a particular individual, quite soon there will be enough left-to-right difference in the dentition that it will re-shape the cheek teeth. Then, very commonly, the new shape will actually block the horse's ability to chew symmetrically -- now he is in a rut that he cannot get out of by any effort of his own.

(3) He will increase his efforts to bring the cheek teeth into occlusion. This works just like an orthodontic "treatment", and will result in the anteriorward rotation of the incisor teeth so that they become "bucked" or protruding to the front. Teeth like this give old horses the reputation of being "long in the tooth". Yes, exactly: they ARE long in the tooth. This can get so extreme that the horse has trouble closing its lips over the front teeth. At the same time, with these horses, there will be a thinning and upward bowing of the lower jaw, and an increase in the size and toughness of the masseter muscles on the jowls. The upward-bowing of the jaws, as well as the rotation of the incisor teeth, are classic examples of "remodeling" as a response to continual unidirectional pressure, i.e. the extreme efforts of the masseters to close the cheek batteries.

(4) Any extreme chewing effort can also have the effect of magnifying any pre-existing imbalance in the mouth. For example, if the horse has a tiny left-right difference, a tiny "hook" on the front or rear end of any cheek battery, a wee space between two teeth which would ordinarily make no difference, or any type of small anomaly relating to the development or eruption of the teeth, these will be magnified into "wave mouth", "Viking funeral ship", "train wreck", and all the other big classic malocclusion patterns that we see affecting the cheek batteries.

(5) And of course, anything that disturbs the normal formation of the incisor battery has a critical impact upon what goes on with the cheek batteries. So if the horse bangs his head on a post and knocks out a tooth....if he has supernumerary incisors....if two of the incisors come in crooked and "impact" or prevent the eruption of another incisor....if the horse has pain that he's chewing away from....if he retains the "caps" on one side ("caps" are remnants of the deciduous premolars that form the fore-end of the cheek battery in younger horses) .... then he will set the wear in the incisor battery awry. The mate to a knocked-out tooth will hyper-erupt until it protrudes beyond the "table" formed by its mates to left and right, and that will create a "lockmouth" -- because of course, the horse's chewing stroke is never to be up-and-down, but rather is down, over, obliquely up-and-across. The incisor teeth must not meet anywhere until the jaw is fully centered, right at the end of the stroke. If you have a lockmouth, the only way the horse can chew is up-and-down, and this in turn will cause him to pound the centers out of his cheek teeth. And THAT in turn will create the biggest "points" you ever saw, and not only that, points that keep coming back -- you can float 'em again and again, and they will keep coming back because you are not addressing the root cause of the problem. In fact, if you want to talk about traditional, supposedly "safe" equine dentistry, you can float a horse to death -- because each time you float the points, you ARE removing tooth substance, and if the practitioner does not know how, or does not believe in, reducing the incisors which are the actual cause, if you keep floating the horse you will eventually remove enough substance from the cheek teeth that NO amount of incisor reduction would be capable of bringing the cheek teeth back into occlusion. This is an important point -- see below.

You say, Pauline, that I am the one person in the world who can rightly answer this query, and you may be right: for to my knowledge, I am the only person who has gone to the effort (over the past decade and more) to look for, document, and properly interpret dental malocclusions in numerous different populations of fossil Equus and in old historical Equus such as my specimens from Roman Vindolanda. And what these studies show is that ALL of the classic patterns of malocclusion, whether affecting the cheek teeth or affecting the incisors, occur in both fossil and in some historical collections. BUT! And this is the big bottom line -- in all populations where it was either before domestication ever occurred, i.e. in Pleistocene or early Holocene equines, or in domestic populations known to have been kept in the field or commons, we see these same malocclusions develop to a TINY extent and only LATE in the horse's life. I can count on the fingers of one hand the number of caries I have seen in fossil horses, and equally rare is any malocclusion of the magnitude we COMMONLY see in modern domestic equines. So there is absolutely no question that it is our practices, our style of horsekeeping, that is causing these problems: whether that relate to processed feeds vs. pasture or to breeding selection and the accumulation of genetic diseases/genetic load -- probably both.

Now we are in a position to judge what constitutes proper equine dentistry. The studies quoted on tooth-heating are quite accurate as to their idea of how hot the tooth has to get before you kill the crucial odontoblast layer. What is not stated (where, O where, are the critical reviewers for veterinary journals? I have often wondered --) is that: (a) the experiments were done on teeth from skulls, not on live horses; (b) they do not accurately reflect real field conditions, i.e. how hot real dentists' equipment actually gets patients' teeth; (c) they do not accurately or fairly represent the practices of competent, properly trained equine dentists; (d) they do not take into consideration the age or health status of the individual horse; and, unfortunately also (e) the articles were produced in a charged political atmosphere, as a way to scare customers and to give legal weight to arguments that equine dentistry should not be practiced by laymen -- in other words, overall it is dishonest science.

I have been observing equine dentistry for better than twenty years now, and have personally witnessed thousands of equine dental treatments, most which included incisor reductions, and I have seen ZERO tooth abscesses or killed (black and/or "dead") teeth as a result of such treatment. Long ago, incisor reductions as well as "table work" on the cheek batteries were still sometimes performed with hand floats, and then there was a switch to using cable-driven Dremels fitted with diamond cutting wheels. These made cutting the teeth easy and quick. Today, we have progressed to the point where several manufacturers make dental cutters and drills specifically shaped for the equine mouth. Some of these are fitted with small tubes that apply a continuous stream of cool water to the tooth being cut, just as do your human dentist's tooth cutters and drills. But even where water cooled equipment is not being used, it is sufficient in HORSES (whose pulp cavities are usually far deeper below the surface being cut than in humans) if (a) the cutting blade is sharp, and (b) the practitioner does not force the edge of the cutter into the tooth (this makes the cutting faster, but also raises the temperature).

Now, as to how much heating a horse's tooth can take: it largely depends upon the age of the horse. I have witnessed one incisor reduction, performed on an 18 year old mare by a practitioner in a hurry and using a dull blade. The incisor was heated until it glowed red! And the horse suffered absolutely no harm whatsoever -- the tooth never abscessed, never turned black, never died -- I had contact with this animal off and on for more than 10 years after the treatment was performed and I know she still had a full set of healthy, albeit geriatric, incisors on the day she died. If you tried this, however, on a younger horse, or perhaps on a different individual, the outcome might not have been so good. For exactly because of the dentine laying-down process mentioned by Easley, as a horse ages the pulp chamber retreats toward the root. It also becomes smaller and more senescent; those of the cheek teeth eventually actually die, but in the incisors the pulp chamber usually does not die or have its circulation completely cut off by natural processes before the horse dies.

So the point here is that the younger the horse, the more knowledgeable, careful and experienced the practitioner must be, because in younger horses the pulp chamber is closer to the occlusal table of the tooth. You may know whether the pulp chamber has been cut into during a reduction if blood spurs forth from the "star", which is the ghost of the top of the pulp chamber as visible on the tooth table. A tiny pinprick of a bleed is as deep as the practitioner dare go, for it signals the top of the pulp chamber and that capping layer of odontoblast cells. If the pulp chamber is cut into broadly, yes, certainly then bacteria will instantly invade and the likely result is an abscess while the tooth as a whole will probably die. What the knowledge, care, and experience" part of this relates to, then, is that you can't directly SEE where the top of the pulp chamber is in the incisor. You can see it absolutely on an X-ray, but X-rays are not generally taken in the field prior to dental treatment; instead, we rely on the practitioner's prior experience with horses of that age and type. And this is usually sufficient. Perhaps as training relating to equine dentistry improves in the world's veterinary colleges, we will see X-rays more commonly used, and absolutely nobody could object to that. But at the present time, most veterinary technicians who specialize in radiography are not trained to take good dental views, and I have seen only one practitioner who regularly did an excellent job taking this type of X-Ray.

This bring us, then, to the answers to your questions:

(1) Should incisor reductions be performed? Yes -- whenever a thourough and competent manual and visual examination demonstrates that they are necessary. Not to perform an incisor reduction when it is necessary is malpractice. The practitioner who lacks a full and correct understanding of equine oral biomechanics, as well as embryology, tooth ontogeny, phylogeny, and geometry, is inadequately trained whether he does, or does not, hold a veterinary license.

(2) Are incisor reductions safe? Yes -- when performed with the appropriate power equipment, with the horse appropriately sedated (sedation MUST BE performed by a licensed veterinarian, whether or not the treatment is performed by a layman).

(3) Excessive removal of tooth substance, whether during incisor reductions, in the creation of "bit seats", or in floating, is malpractice. Tooth substance has been removed in excess when the pulp chamber is exposed, when the odontoblast layer is harmed, or when the tooth has been weakened by the treatment.

You will see from the above that the statement "this 7 year old horse has the teeth of an animal twice its age" would be nearly impossible. But -- just possible -- if the horses this veterinarian is seeing are in fact being butchered by some incompetent practitioner wielding power equipment. If thye vet is treating abscesses caused by exposure of the pulp chambers in any of the teeth, then we have to believe that he is treating abscesses. What we do not have to believe -- or where you might say the break is in the logic here -- is that ALL incisor reductions should stop. Incisor reductions are no more dangerous than what is called "ordinary" floating, which also removes tooth substance.

As an aside: yes, there are ways other than dental treatment to produce pulp abscesses. All that is required is that the pulp chamber be invaded, and this is what the bacteria that cause tooth "cavities" (caries) are in business to do. We have in the last 20 years in the U.S., but it is a newer phenomenon in Australia, turned more and more to feeding bagged mixes that have huge amounts of molasses. Our skull collections document a steep rise in the number and seriousness of caries that exactly parallels the introduction and then increasing availability and popularity of these overly-sugary bagged feeds. It is possible that the veterinarian who is stomping and snorting about pulp abscesses is, in fact, seeing the effects of this type of feeding rather than incompetent dentistry. If he is seeing a lot of pulp abscesses in the cheek teeth, I would suspect feed before dentistry as the cause.

What is obvious from all of this is the importance of REGULAR dental maintenance beginning at birth. If the owner didn't wait until the horse is past 12 and starting to show those occasional colics or dribbling that feed or dunking or butting his hay because he can't chew the stems properly, then so much incisor would not have to be removed. Again: there is little danger in incisor reductions when the dentistry performed has as its object merely to bring the cheek teeth back into proper occlusion, and/or to eliminate blockages or asymmetries that are of small magnitude.

Now, to conclude, I want to repeat something I've said several times here before: I am looking for grownups in this system. I left the dental school where I had taught for a decade because the leaders in that school are unethical. They have no intention of playing by any agreed-upon set of rules: they supply their favorites with drugs under the table; they confer certificates and pseudo-degrees upon people who could not pass any of the certifying examinations now being offered in several places around the world; and they promote to high office people who are complete kooks. I witnessed the leaders of that school grant certificates primarily because they were afraid that the student "wouldn't like them" if the passing status was not conferred. I tried for years to get the leaders of that school to learn basic concepts of biology, embryology, and anatomy -- to no avail.

What they want, they say, is to have equine dentistry recognized as an "independent profession". This would be OK if what they really meant was that it be handled the same way as we handle human medical vs. dental treatment: both the doctor and the dentist are highly educated and trained, but their training, though it overlaps in some areas, focuses on different aspects of health care. I don't go to my doctor to have my teeth attended to, and I imagine you don't, either.

But this is not what this school of people means by "independent". What they mean is that they want not to be regulated at all. They want to be able to administer phamaceutical drugs without meaningful supervision by a veterinarian. This, because it so much reduces the inconvenience to them and the expense to their customers, and because it so much increases their freedom to act, and to practice, where they choose. For this reason the Board of Veterinary practice, along with the District Attorney's office in several U.S. states, has pursued and prosecuted a number of these guys. In my opinion, this has been the wrong tack to take, just as publishing "scare science" is the wrong tack to take. The right approach is to develop a meaningful certification examination, so that all those who wish to practice equine dentistry in a given state, or nationally, would know ahead of time exactly what they are required to know. This should be followed by a meaningful practical examination. The successful candidates would be issued legally-actionable certificates or licenses, and this is necessary so that when malpractice occurs -- and mind you, it occurs both among veterinarians and laymen -- the horse owner has a plain and well-trodden path to recompense and/or punishment of the offender. This is the same playing field your veterinarian has already agreed to, and it should apply equally to anyone in the animal health-care field.

Now, I say I have been looking for grownups in this controversy, and I have been disappointed with the attitude of some of the laymens' groups. I have equally been disappointed with some of the veterinarians. I know of cases where a veterinarian submitted to being taught by a highly skilled layman, then went back to his home university and published papers detailing what he had learned yet without giving any credit to the man who had actually taught him; the veterinarian claimed he had learned it all in vet school. How totally ungentlemanly, and how totally unprofessional -- something that veterinarian Tom Allen of Missouri , who learned his dentistry from laymen, has stated in a letter he shared with me addressed to the AVMA and AAEP. I have personally witnessed veterinarians who were among the worst dental practitioners I have ever seen or could imagine. I have photographic evidence of malpractice, leading to the death of a horse through the total misinterpretation of the teeth, by a veterinarian. I have heard veterinarians say things that proved they were mixed up, or even quite ignorant, about equine oral biomechanics and tooth development. And -- maybe this is human nature -- but unfortunately, the least knowledgeable and most incompetent veterinarian is almost always the one who screams loudest when the highly-trained, more experienced layman comes to town who can be the one who finally satisfies the dental needs of horses in the area.

And this is the real bottom line: the horses need us to grow up and get real about providing proper, competent equine dental services. There are groups all over the world now (and I know because I am working with several of them), composed of veterinarians who ARE properly trained and who ARE willing to work in a gentlemanly, professional manner with laymen who are totally willing to work WITH the vets and under their supervision when that is needed to protect the safety and health of the animals, and who ARE willing to study hard for a meaningful test and then be legally regulated in practice.

You as consumers, and some of you as alternative health-care practitioners, can and should look with a wary eye upon anyone who offers equine dental services. This Internet memo is far from sufficient to teach all that there is about "horse teeth", but may serve as some guideline. I do have hopes for the rational resolution of this problem, so that it ceases to be a controversy. For indeed, if every veterinarian now licensed quit practicing anything but equine dentistry tomorrow, we would still not be able to supply the needs of all the domestic horses that would benefit from seeing a dentist. There is plenty of room for all concerned, and my hope is to see committed individuals working together to provide the services that all our horses need. -- Dr. Deb

 

Tasha
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 Posted: Wed Mar 4th, 2009 11:32 pm
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I know that this has been Pauline's thread but I wanted to say thank you Dr Deb for the information you make so freely available in your forum. Your answer is as insightful as ever, and has allowed me to make a paradigm shift. I apologise for my first post to this thread being so anti-layman dentist and I freely acknowledge that out in big wide world there are laymen out there who are great dentists and there are vets who are bad dentists.

Pauline Moore
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 Posted: Thu Mar 5th, 2009 11:55 pm
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Dr Deb,  thank you once again for such a wonderful reply.

I'm still pondering on the likely cause of these abscesses as, in my own mind, I am confident that poor dentistry is not responsible.  I'm getting the impression that most, if not all, of these reported abscess cases are occurring in the coastal areas of northern NSW and southern Queensland which are predominantly pastured with imported tropical high-sugar grasses such as kikuya etc.  Prior to the last 9 months or so, these areas have been in severe drought for a long time but since then have had an abundance of rain and a consequent abundance of grass.

I have read that magnesium is essential for producing hard tooth enamel and know that horses exposed to high-sugar pastures are in need of extra magnesium to assist with metabolizing the excess sugars, so I'm wondering if these horses could have become magnesium deficient (and/or other minerals also) during the drought period and therefore are using whatever magnesium resources they have for food processing and other essential body systems rather than maintaining good quality tooth enamel.  Could this be a factor in a horse developing caries that then allow entry of bacteria to the tooth pulp?  Does the naturally occurring sugar in grass start to be released at the beginning of the digestive process in the mouth?  Or does that happen at a later stage in the stomach or intestines?  Could grass sugars alone be responsible for dental caries in cases of magnesium deficiency even without sugary processed feeds?

Any thoughts would be appreciated.

Best wishes - Pauline



DrDeb
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 Posted: Fri Mar 6th, 2009 06:55 am
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Pauline -- have a look in your copy of the Poison Plants book (p. 309) under Kikuyu, and you will see that it is associated with 'big head', which is a syndrome ('nutritional secondary hyperparathyroidism') involved with the disturbed/inadequate metabolism of sugar, magnesium, and calcium -- the latter two, of course, being essential tooth-building minerals. So if foals are being raised on Kikuyu grass or hay, yes, they could certainly wind up with poorly-mineralized teeth and bones.

So you have that route to go. Meanwhile since posting the above, I have thought of a couple of other things to add, as to likely causes for tooth abscessing/premature exposure of the pulp cavity:

(1) In cheek teeth: if the horse has not had incisor reduction/reshaping when it should have been done, and if this has forced the loss of jaw excursion (i.e. its ability to travel through the whole lateral extent of the chewing stroke); and if this in turn has resulted in the animal pounding the centers out of the cheek teeth, then this will certainly, in addition to creating big, persistent 'points' as discussed above, also tend to unroof the twin pulp cavities that lie toward the centers of the cheek teeth.

(2) In either cheek teeth or incisors: excessive reduction of tooth substance is not the only cause for abscessing in 'sound' and normally-developed teeth. The most common cause of tooth abscesses is that the teeth have been cracked, and/or that an extraction was performed but the practitioner failed to remove all the sherds. If even one bit of the tooth is left in the alveolus, it will abscess, and this can be a real mess when a better practitioner has to go in and pick out small sherds. In the old days, teeth were sometimes fractured by old-fashioned molar cutters -- and it happened to even the best of practitioners, simply because this is a difficult operation, particularly as you get toward the back of the mouth. This is one major reason why rotary power equipment is MUCH better -- incisors are not the only teeth that may need to be reduced, and adapted rotary power equipment never causes cracking or fracturing. Note that horses who pick up hay, or to graze, among small gravel can sometimes by accident get a rock in the bolus and chomp down on it and thus crack their own teeth -- I have seen two cases where this was the likely etiology, as no dentist had seen those horses and they were kept on range.

(3) The more you have teeth that are poorly-mineralized, the more likely it is that the centers of the infundibulae (the 'enamel lakes' or 'fossae' of the cheek teeth, the 'cups' of the incisors) will not be fully infilled with cementum as they should be. They will not be filled all the way to the top, and there may also be a hole which is of toothpick-diameter or larger that goes right down the center from the occlusal table to the base of the crown internally. When the infundibulae have a hole in them like this, the hole provides an easy route of entry for bacteria that goes deep down into the tooth. When a horse with unfilled infundibulae eats, he will pound the foodstuff down into the cylindrical infundibulum. So common is this phenomenon that we know what the grassy diet of Pleistocene horses was, through simply picking the grains and bits of blade out of the infundibulae -- for they remain there even after death and fossilization! What we find in the teeth of Pleistocene horses are the normal 'wild' grasses that used to occur, and still occur, throughout the undeveloped parts of the Northern Hemisphere. These grasses do not cause caries -- I've said above these are very rare in fossil horse populations. However, if the foodstuff is sugary, such as are many of our so-called improved grasses, or if it is sugary bagged feed, then caries are sure to follow. But caries that attack the inner surfaces of the infundibulae cannot be seen except on X-ray. The enamel coating which defines the margins of the 'lakes', especially in the cheek teeth, is mostly thinner than that which jackets the external aspect of the teeth; hence, caries that begin within the infundibulum will likely progress faster than those that begin just above the margin of the gums.

I don't really believe that the horse you're describing is the victim of incompetent dentistry. I've heard the particular veterinarian you're speaking of make similar claims against tooth reductions before, so that clients think he's their only last hope; but interestingly, his rates are extremely high. So rather than have your clients think that they must choose between what this guy is offering vs. euthanasia, I would suggest that the horse owner seek the opinion of several of the best lay and veterinary dentists she can locate in her area. No question, if the teeth are abscessing, they must be extracted. But the rates she is being quoted are of a size that tells me that this vet intends to do lay-down surgery with full anaesthesia and clinical post-op care. Perhaps that really is going to be necessary; one must judge on the merits of the case. However, it may also mean that he does not know how, or lacks the skill and experience, to perform stand-up extractions, which are universally much less expensive. One of the great contributions of the lay dentists has been to improve the speed and efficiency of extractions in many, if not all, cases. -- Dr. Deb

horsemicrobiology
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 Posted: Sun Mar 8th, 2009 12:52 pm
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Hi Pauline

I understand your frustration as there is so much information out there and it is extremely difficult when you get two specialists in the same field with conflicting evidence. 

There is growing evidence that some Australian trained equine dentists are using their tools incorrectly.  My advice to you would be to look at the science.  Horses teeth should not be filed down to leave the pulp exposed, this will age the horses’ teeth dramatically.  It leaves the tooth exposed and to put it in simple terms, if you did that to a humans tooth, you would be sued and charged. 

Unfortunately the number of cases in which poor dental work has resulted in abscesses is on the rise.   I have consulted a number of vets, surgeons and dentists both in the equine and human field and they all agree, you should never file the tooth down so the pulp is exposed.  There is no scientific or logical reason for doing this and can be considered cruel. 

You should consult a equine dentist who is also a vet as he/she will have the means to x-ray your horses mouth.  A vet who specialises in equine dentistry has a greater understanding of the physiology of the horses mouth and has the background medical experience that a normal dentist would not.

Hope this helps.

 


 

 

 

 

DrDeb
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 Posted: Sun Mar 8th, 2009 09:19 pm
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Dear Horssemicro: so much is obvious from the extensive information I have given above. No one questions that premature exposure of the pulp that occurs as the result of dental procedures is malpractice. If there is a practitioner out there who is cutting so deeply into the teeth that the pulp cavities are exposed, whether that individual is a veterinarian or a layman, they need to be stopped.

This does NOT mean that incisor reductions should not be performed.

Premature exposure is in my experience very rare, as is heat-induced damage to horse teeth from rotary equipment.

So again I want to emphasize: the MOST COMMON reasons for pulpal abscessing are:

(1) The premature exposure of the pulp cavities in cheek teeth due to the failure of the dental practitioner to properly equilibrate the mouth, i.e. their failure to reduce the incisors as part of the proper treatment for an animal that is pounding the centers out of its cheek teeth. In this case, it is the abnormal up-and-down action of the jaws (forced on the animal because the shape or length of the incisors prevents normal side-to-side excursion) that unroofs the pulp cavities, not any dental procedure.

(2) Fractures to the teeth, which come either from accidents during cheektooth reductions using molar cutters, incomplete extractions that leave sherds in the alveolus, or instances where the horse has hurt himself by biting down on a rock (cheek teeth) or by cracking his muzzle against a post (incisors).

(3) Caries that penetrate to the pulp cavity, either from the gumline externally, or via the infundibulum (especially in cases of incomplete/poor mineralization of the teeth).

It is my purpose, Horsemicro, in this Forum to dampen or eliminate the expressions of anyone who posts for "political" reasons. If you are a veterinarian making noise about "an increasing frequency of pulpal exposures", then before I permit you to mention this again, you will have to present survey documentation of the trend you think you see. And, you will also have to show that the increase is, in fact, due to poor dental practices rather than any of the array of other (and more likely) causes which I have outlined above. Scare tactics and political posturing will not be permitted here. If you have good information to share, then you may do that. I want to see that your primary motivation is to help the horses, rather than to help yourself or line the pockets of some guru whom you follow. So, as a prerequisite to permitting you to post here again, I will require in your case that you post using your true name. Transparency must be the first law in this discussion. -- Dr. Deb

horsemicrobiology
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 Posted: Sun Mar 8th, 2009 09:52 pm
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Hi Dr Deb

 I am from Qld, Australia, please forgive me as I am new to this forum, are you aswell from Queensland Australia?  Secondly, are you a Dr, Vet?  Thank you for your quick reply.  I believe that talking about this issue is the first step to resolving and I think its great that we are able to share our different knowledge.

 I have been lucky enough to view an array of photos taken of these horses mouths where their front teeth have been filed down by a diamond drill to expose the pulp, this in conjunction with the overheating of tools has lead to pulp death. 

Pauline - it is this reason that human dentists have water that squirts out while they are filing down our teeth.  Unfortunately the photos I studied show clear misuse of tools and have ruined these horses teeth beyond repair.  The pulp cavity, as we all know should be hard, but in these horses they are as extremely soft as the vet who took these photos was able to stick one of his probes right into it.

Obviously there are other reasons that can cause tooth abscesses, however in the case it is my belief that alot of them have been caused by poor dentistry.  It is a shame because I do not believe these people know the damage they are causing. When I consulted experts they couldn't find any logical reason for these people doing this.

I am extremely interested in seeing how this unfolds over the next few months and years.  Dr Deb people here are starting to send complaints into the board about this so it will be interesting to watch how it unfolds. 

Looking forward to your reply

 

 

 

DrDeb
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 Posted: Sun Mar 8th, 2009 11:18 pm
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Horsemicro -- this will be your last opportunity to communicate in this Forum under a pseudonym. You will henceforth post under your own true name, as I do, and as Pauline Moore does. If you post even one more time under a pseudonym, we must assume that you have something to hide, and such persons are not welcome here. Posts from you under any name but your own from henceforth will be pulled, and your access to this Forum will be blocked.

I am not from Queensland, but have taught there, in NSW, and in SA for years. I am quite familiar with conditions in your part of the world. I am also personally acquainted with many veterinarians and laymen in your country who practice equine dentistry. I know who is confused and who is not, and as I have already said, there are problem veterinarians as well as problem laymen.

As to my qualifications, you may view them by going to "Friends of the Institute", where the brief bio is posted. My degree is Ph.D. and the title is vertebrate paleontology, a degree which requires extensive training in animal anatomy.

For better than 25 years, I have taught equine anatomy to anyone who cared to either read the publications, or enroll in a class. My work has been featured in every major horse publication, and I am a major contributor to the prestigious Animal Science Encyclopedia published by Elsevier Scientific. I have been an invited speaker to many veterinarians' organizations, and to dental organizations where the audience included both laymen and veterinarians. My anatomy classes are now recognized by the American Association of Equine Practitioners, a subgroup of the American Veterinary Medical Association, for continuing education credit for licensed veterinarians. This is a great honor, and an acknowledgement that the education and experience of a non-veterinarian can, at a high level, be of benefit to licensed veterinarians. 

Your own fears and concerns about equine dentistry might be greatly relieved if you would sign up for one of the anatomy classes which we have scheduled for this April in Tamworth, NSW. Contact and enrollment information is posted under "Catching up with Dr. Deb".

Our readership here should also be alerted to the fact that currently, there is a telephone campaign -- I do not know who is promoting it -- within Australia, where horse owners are aggressively being solicited to testify against lay dentists. This is an underhanded way of pressuring people who don't always have all the facts, and who are not in a position to discriminate, into testifying. It's a tactic that has previously been tried, without great success, in the U.S. In other words, it is politics, not science, and should be beneath the notice of quality practitioners AND horse owners alike. 

There is a movement currently, worldwide, to bring the most qualified people into the field of equine dentistry. Many veterinarians do not care, or are not physically able, to perform the tasks that equine dentistry would require. In view of the fact that there are many horses who need care, and owners who are demanding better care, we are working to develop meaningful training and certification which ANYONE -- licensed veterinarian or layman -- who wishes to practice equine dentistry would have to pass. This is the right way to go. It is absolutely foolish to assume that just because someone has a veterinary license, that that automatically qualifies them to practice animal dentistry. Animal dentistry requires extensive, specialized training and I am one of those in the international community committed to seeing that we make all the changes necessary to see to it that any animal that needs it receives proper help from a qualified practitioner. --

Dr. Deb Bennett, Ph.D., Director

Equine Studies Institute

Livingston, California

 

 

Last edited on Sun Mar 8th, 2009 11:28 pm by DrDeb

JTB
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 Posted: Mon Dec 3rd, 2018 06:47 pm
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I was looking up Tooth abscess and found this excellent thread-- bumping it so I can find it again later. I have a new vet/dentist coming this week as Little might have a tooth abscess. I am doing some study to refresh my memory :-)
Many thanks for the wonderful information provided in this forum.
Kind Regards
Judy

DrDeb
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 Posted: Mon Dec 3rd, 2018 09:02 pm
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Judy, I'll be interested to hear the whole tale about this, especially since I know the horse well. And if the vet takes digital XRays if you could ask him to give you copies on a disk, and then possibly EMail some of them to me. Cheers -- Dr. Deb

JTB
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 Posted: Tue Dec 4th, 2018 05:45 am
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We see the vet/dentist on Thursday and I will happily give you copies of any x rays and let you know the tale. :-)
Thanks heaps.


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