overshot jaw dog factory

An overbite might not seem like a serious condition for your dog, but severely misaligned teeth can lead to difficulty eating, gum injuries and bruising, bad breath and different types of dental problems, including tooth decay and gingivitis. Fortunately, there are ways to help fix the problem before it becomes irreversible.

An overbite is a genetic, hereditary condition where a dog"s lower jaw is significantly shorter than its upper jaw. This can also be called an overshot jaw, overjet, parrot mouth, class 2 malocclusion or mandibular brachynathism, but the result is the same – the dog"s teeth aren"t aligning properly. In time, the teeth can become improperly locked together as the dog bites, creating even more severe crookedness as the jaw cannot grow appropriately.

This problem is especially common in breeds with narrow, pointed muzzles, such as collies, shelties, dachshunds, German shepherds, Russian wolfhounds and any crossbred dogs that include these ancestries.

Dental examinations for puppies are the first step toward minimizing the discomfort and effects of an overbite. Puppies can begin to show signs of an overbite as early as 8-12 weeks old, and by the time a puppy is 10 months old, its jaw alignment will be permanently set and any overbite treatment will be much more challenging. This is a relatively narrow window to detect and correct overbites, but it is not impossible.

Small overbites often correct themselves as the puppy matures, and brushing the dog"s teeth regularly to prevent buildup can help keep the overbite from becoming more severe. If the dog is showing signs of an overbite, it is best to avoid any tug-of-war games that can put additional strain and stress on the jaw and could exacerbate the deformation.

If an overbite is more severe, dental intervention may be necessary to correct the misalignment. While this is not necessary for cosmetic reasons – a small overbite may look unsightly, but does not affect the dog and invasive corrective procedures would be more stressful than beneficial – in severe cases, a veterinarian may recommend intervention. There are spacers, braces and other orthodontic accessories that can be applied to a dog"s teeth to help correct an overbite. Because dogs" mouths grow more quickly than humans, these accessories may only be needed for a few weeks or months, though in extreme cases they may be necessary for up to two years.

If the dog is young enough, however, tooth extraction is generally preferred to correct an overbite. Puppies have baby teeth, and if those teeth are misaligned, removing them can loosen the jaw and provide space for it to grow properly and realign itself before the adult teeth come in. Proper extraction will not harm those adult teeth, but the puppy"s mouth will be tender after the procedure and because they will have fewer teeth for several weeks or months until their adult teeth have emerged, some dietary changes and softer foods may be necessary.

An overbite might be disconcerting for both you and your dog, but with proper care and treatment, it can be minimized or completely corrected and your dog"s dental health will be preserved.

We advise you email us images of the teeth (mouth closed, lips up and side on for both left and right) just a few days before you travel. Things change quickly in growing dogs and it might save you a wasted journey.

Secondly, the growth of the mandible is rostral from the junction of the vertical and horizontal ramus. If the lower canines are embedded in pits in the hard palate, the normal rostral growth of the mandible(s) cannot take place normally due to the dental interlock caused by the lower canines being embedded in hard palate pits. This can cause deviation of the skull laterally or ventral bowing of the mandibles (lower jaws).

Thirdly, the permanent lower canine is located lingual to the deciduous canine. This means that if the deciduous lower canines are in a poor position it is a certainty the permanent teeth will be worse. See the radiograph below. The deciduous canines are on the outside of the jaws and the developing permanent canines are seen in the jaw as small "hats". It is clear that the eruption path of the permanent canines will be directly dorsal and not buccally inclined as is normal.

The permanent successor tooth is located lingual to the deciduous tooth and wholly within the jaw at this stage. Any use of luxators or elevators on the lingual half of the deciduous tooth will cause permanent damage to the developing enamel of the permanent tooth. See the images below showing canines (and also the third incisor) with extensive damage to the enamel. The radiograph also shows how much damage can occur to the teeth - see the top canine and adjacent incisor. Some severely damaged teeth need to be extracted while other can be repaired with a bonded composite. This damage is avoidable with careful technique using an open surgical approach.

Do not try ball therapy with deciduous (puppy) teeth. There are two main reasons for this. Puppy teeth are fragile and can easily break. More importantly, the adult canine tooth bud is developing in the jaw medial to the deciduous canine tooth (see radiograph above in the puppy section). If the deciduous crown tips outwards the root will tip inwards. This will push the permanent tooth bud further medial than it already is.

These permanent teeth can theoretically be treated by three options. Not all options are available to all cases. These options are described below and are either surgical removal of the lower canines teeth (and possibly incisors also), crown amputation and partial pulpectomy or orthodontics via an inclined bite plane bonded to the upper canines and incisors. The latter option may not be available to all dogs if the diastema (space) between the upper third incisor and canine is too small for the lower canines to move into or if the lower canines are located behind (palatal) to the upper canines.

This is a very delicate procedure and carries very high success rate (in our hands) since the availability of Mineral Trioxide Aggregate (MTA). We have used it as the material of choice since 2005. The previous agent (calcium hydroxide) was much more caustic and tended to "burn" the pulp. The success rate of MTA treated cases is quoted as 92% in a seminal ten year study based in vet dental clinics in Finland. This compares with 67% when caclium hydroxide was previously the agent. Luotonen N et al, JAVMA, Vol 244, No. 4, February 15, 2014 Vital pulp therapy in dogs: 190 cases (2001–2011).

The intention of the procedure is to keep the pulp alive and allow the shortened lower canines to develop normally and contribute to the strength of the lower jaws.

The advantage of this procedure is that the whole of the root and the majority of the crown remain. The strength and integrity of the lower jaw is not weakened by the procedure and long term results are very good due to the use of Mineral Trioxide Aggregate as a direct pulp dressing.

However, many owners are concerned (rightly) about the loss of the tooth and the weakness it may cause to the lower jaw(s). It is not our preferred option. This is not an easy surgical extraction and the resulting loss of the root causes a weakness in the lower jaws. This is compounded if both lower canines are removed.

In some mild cases of lingual displacement we may be able to use crown extensions for a few weeks. For this treatment we bond composite resin extensions on the lower canines to increase the crown length by around 30%. This allows the lower canines to occupy the correct position and also provides more leverage to tip the crown tips buccally. The crown extensions remain in place for around 2 months and are then removed and the tooth surface smoothed and treated. The major downside is that if the dog damages or breaks them off, you need to return here for repairs. Sticks and other hard objects can easily cause damage and some toys also have to be withdrawn for the treatment period.

Normally a composite resin bite plane is bonded onto the upper teeth (see below) with an incline cut into the sides. The lower canine makes contact with the incline when the mouth closes and, over time, the force tips the tooth buccally. This takes around four to eight weeks. The lower canine will often migrate back into a lingually displaced position when the bite plane is removed. This can occur if the tooth height of the lower canine is too short (stunted). If the lower canine is not self-retained by the upper jaw when the mouth is shut further surgery may be required.

Not all dogs or owners are suited to this. Bite planes can become dislodged if the dog bites a stick or other hard object. Bite planes also need cleaned and adjusted from time to time under sedation or anaesthesia. All of this means more travel and expense for you and more anaesthesia for your pet. It is our view that if a treatment has uncertain outcomes built in it should probably not be used.

Bite faults are one of the first hereditary defects a fledgling dog breeder learns to recognize.  Teeth are right out there where everybody can take a look at them.  Once you learn what is right for your breed, it isn’t difficult to recognize what is wrong.  Though a dedicated cheat may “improve” a dog’s bite through orthodonture, there are limits to what can be done.  For the most part, what you see is what you’ve got.

In order to fully understand bite faults, you must also understand what is correct and why.  This goes beyond having the right number of the right teeth in the right places.  A dog’s dental equipment is a direct inheritance from his wild carnivorous ancestor, the wolf.  Dog dentition is also very similar to the wolf’s smaller cousin, the coyote.  Figure 1 is a coyote skull, exhibiting a normal canine complement of teeth.  Each jaw has six incisors at the front, followed by two canines, then eight premolars (four to a side).   When we come to the molars, the top and bottom jaws differ.  The lower jaw has six and the upper only four.  A normal dog will have a total of 42 teeth.

The canines are most critical to catching and holding prey.  Readers familiar with police K9s or Schutzhund will know that the preferred grip is a “full mouth bite:”   The dog grasps the suspect’s arm or leg well into its mouth, between its molars and premolars and behind the canines.  This is not the way a wolf does it.A wolf grips with the front of his mouth.  The four canine teeth puncture the prey. Their overlapping structure (see Fig. 2)combined with jaw strength prevents the prey animal from pulling free.   When catching bad guys, the idea isn’t to poke them full of holes and have them for dinner, but to hang on until the guy with the gun and the handcuffs arrives.

Once the prey is down, the premolars are used for biting off chunks of meat that are swallowed hole.  The 4th upper premolar and the first lower molar on each side, the carnasals, are especially developed for this task.  (Fig. 3)  These are the most massive teeth in the canine jaw.  They are very sharp and their location mid-way down the length of the jaw puts them at the point where jaw pressure is greatest.

All these specialized teeth are not independent entities.  Their position in the jaw is determined by their function and they require a properly formed skull and lower jaw to function efficiently.  The muzzle must be long enough and broad enough to accommodate the teeth in their proper locations.  The animal must have sufficient bite strength to hold onto whatever it has grabbed, be it prey or perpetrator.  Jaw strength comes not only from the muscles, but the shape of the skull.

Figure 4shows the skulls of a coyote and an Australian Shepherd.  Aussies have normally-shaped heads, so the shape of its skull is very similar to that of the coyote.  The jaw muscles attach to the lower jaw and along the sagittal crest, the ridge of bone along the top and back of the skull.  In between it passes over the zygomatic arch, or cheekbone.  Wrapping around the cheekbone gives the bite much more strength than would a straight attachment from topskull to jaw.  This attachment also serves to cushion the brain case from the flailing hooves of critters that don’t want to become dinner or get put in a pen.

You will note that the crest on the coyote is more pronounced than on the Aussie and its teeth are proportionally larger.  This is a typical difference between domestic dogs and their wild kin.  Wild canids need top efficiency from their dental equipment to survive.   We have been providing food for our dogs for so long that the need for teeth as large and jaws as strong as their wolf ancestors has long passed.

Jaw strength is reduced in the dog by a less acute angle around the zygomatic arch.  Note the more pronounced angle in the coyote (Fig. 5a)  as compared to the Aussie  (Fig. 5b).This is another typical difference between wolf or coyote and dog skulls.  The larger sagital crest allows for a larger, and therefore stronger, muscle.   The only breed with an angulation around the zygomatic arch that approaches that of the wolf is the American Pit Bull Terrier/American Staffordshire Terrier.  Pit/AmStaffs also have a relatively short jaw, giving their heads a more cat-like structure:  Broad + Short + Strong Muscles = Lots of Bite Strength.

Breeds with long, narrow heads have even straighter angulation around the cheekbone, and therefore an even weaker jaw.  The narrow jaw may also cause crowding of the incisors.   Toy breeds with round heads often have little or no sagittal crest and very weak jaws.   Short-muzzled breeds may not have room for all their teeth resulting in malocclusion, meaning they don’t come together properly.  The jaws of short-muzzled breeds may also be of unequal lengths.

The more we have altered skull and jaw shape from the norm, the less efficient the mouth has become.  In some cases, this isn’t particularly important.  There is no reason for a Collie or a Chihuahua to bite with the strength of a wolf.  However, jaws that are so short it is impossible for all the teeth to assume normal positions and undershot bites that prevent proper occlusion of the canines and incisors are neither efficient nor functional, despite volumes of breed lore justifying those abnormalities in breeds where they are considered desirable.

Now that we know what is “right,”  for most breeds, anyway, and why it is right, let’s look at what can be wrong, why it is wrong and what, from a breeding standpoint, can be done about it.  Most breeds with normal skull structure were originally developed to perform a function (herding, hunting, guarding, etc.)  Since that structure is the most efficient it was maintained, with minor variations, in most functional breeds.   Typical dental faults in these breeds are missing teeth and malocclusions.  It is evident that these faults are inherited, but not a great deal is known about the specifics of that inheritance.  In some breeds, some defects appear to have a simple mode of inheritance, but this is not the case across all breeds.  That, plus the complex nature of dental, jaw and skull structure, indicates that in most cases the faults are likely to be polygenic, involving a group of genes.

Missing teeth obviously are not there to do the work they are intended for.  They should be considered a fault.  The degree of the fault can vary, depending on which teeth and how many are missing. The teeth most likely to be absent are premolars, though molars and sometimes incisors may occasionally fail to develop.   Missing a first premolar, one of the smallest teeth, is much less a problem than missing an upper 4th premolar, a carnasial.   The more teeth that are missing, the more faulty and less functional the bite becomes.  If you have a dog with missing teeth, it should not be bred to other dogs with missing teeth or to the near relatives of such dogs.  Though multiple missing teeth are not specifically faulted in either Australian Shepherd standard, you should think long and hard before using a dog that is missing more than a couple of premolars.

Malocclusions most frequently result from undershot and overshot bites, anterior crossbite and wry mouth.  An undershot bite occurs when the lower jaw extends beyond the upper.  This may happen because the lower jaw has grown too long or the upper jaw is too short.  Selecting for shorter muzzles can lead to underbites.  An overshot bite is the opposite, with the upper jaw longer than the lower.  In either case, the teeth will not mesh properly.  With slight over or undershot bites, the incisors may be the only teeth affected, but sometimes the difference in jaw length is extreme (Fig. 6)

leaving most or all of the teeth improperly aligned against those in the opposite jaw.  A bite that is this far off will result in teeth that cannot be used at all, teeth that interfere with each other, improper wear and, in some cases, damage to the soft tissues of the opposite jaw by the canines.

In wry mouth, one side of the lower jaw has grown longer than the other, skewing the end of the jaw to one side.  The incisors and canines will not align properly and may interfere.  It is sometimes confused with anterior crossbite, in which some, but not all, of the lower incisors will extend beyond the upper incisors but all other teeth mesh properly.

Minor malocclusions, including “dropped” incisors and crooked teeth, also occur in some dogs.   Dropped incisors are center lower incisors that are shorter than normal.  Sometimes they will tip slightly outward and, when viewed in profile, may give the appearance of a bite that is slightly undershot.  Dropped incisors tend to run in families and are therefore hereditary.  Crooked teeth may be due to crowding in a too-small or too-narrow jaw or the result of damage to the mouth, though the former is more likely.

Some consider an even, or level, bite to be a type of malocclusion.   Breed standards vary on whether they do or do not fault it.  In the Australian Shepherd, the ASCA standard faults it while the AKC standard does not.  There is clearly no consensus among dog people.  Those who fault the even bite claim that it causes increased wear of the incisors, but there is little evidence to support this.  A number of years ago the author, upon coming across a wolf with an even bite (Fig. 7), undertook a survey of wolf dentition.  Teeth and jaws were inspected on 39 wolves, 9 of which were captive and the balance skulls of wild wolves trapped over a wide span of time and geography.  Of the 39, 16 had even bites.  This included five of the captive group, all of whom were related.  Even discounting those, fully a third of the wild wolves had even bites.  No structural fault is tolerated to this degree in a natural species, particularly in a feature so critical to the survival of that species.

As stated previously, bite faults and missing teeth are likely to be polygenic in inheritance.  Each is also variable in the degree of fault between individuals.  Dogs that have dental faults bad enough to be considered disqualifications under the breed standard ought not to be bred.  Minor bite faults have only minimal impact on the dog’s ability to function.  Before it is bred, the degree of a dog’s dental faults will have to be weighed along with all the other virtues and faults the dog has.  If the dog is then considered worthy for breeding, it should not put to mates of similar pedigree (where genes for the fault clearly lurk,) or to mates from families where the its dental fault is known to occur.  If, when being so bred, the faulty dog throws multiple offspring with the same dental fault, or produces affected pups with different mates, then it should probably be withheld from any further breeding.

The normal relatives of dogs with dental faults can be bred, but since they may carry some genes for the fault.  If you own such a dog, you will want to select mates from families where this is not known to be a problem in order to reduce risk of perpetuating the fault.

So now you know not only whatcan be wrong with a bite, but why.Bite faults are one of the easier hereditary problems to deal with.  Even if you are a relative beginner, with an understanding of dental structure and function you can evaluate the quality of not only your own dog’s dentition, but that of any other dogs whose mouths you might gaze into.  Check out as many as you can and remember who has (or does not have) what and who they are related to.   Armed with this knowledge, you can make informed breeding decisions for your own dogs.

Hell its my $0.02c and your dog, do what you want. Go look at a heap more puppies and wear out that "Oh so cute must have to hold and cuddle" emotion that puppies invoke and think with your long term brain rather than your paternal desire.

ninja edit: +1 pound puppy, have had a few. Now have Pug. Ultimate kids dog. Did lots of research and bought from very reputable breeder and not factory or backyard where problems end up enhanced.

An underbite is when the lower jaw juts out from underneath the upper jaw. In some dog breeds, this is fairly common and is often an identifying trait of a breed. However, it can create some problems for the dog over time. Here’s a list of dogs that are frequently born with an underbite, as well as some ideas about whether or not you should correct this.

Bulldogs are famous for underbites, and it comes with the territory of the breed. It doesn’t matter if it’s an English bulldog, a French bulldog, or an American bulldog. They all have an underbite as a characteristic of their head and jaw structure. Their recessed nasal passages often push the upper jaw back, causing the lower jaw to jut forward a bit. As long as it doesn’t cause major chewing problems or create major dental issues in your bulldog, you don’t really have to correct it.

Many of the small Asian lap dogs suffer from an underbite, and the Pekingese is no exception. The narrow, upturned nose of the Pekingese shares a trait with the bulldog family in that the upper jaws follow the flattened noses. The Pekingese has a v-shaped lower jaw that doesn’t always meet the unusual shape of the upper jaw and nose area. Subsequently, you will see these little dogs with one or more teeth sticking out of the bottom.

Here is another little Asian lap dog that frequently has an underbite. However, the Shih Tzu should have the underbite corrected if possible. It interferes quite a bit with the little dog’s ability to bite and chew. Their little razor-like teeth can cause dental and oral problems too. The only upshot is that it is easier to brush the Shih Tzu’s exposed lower teeth and prevent tooth decay.

Pugs are often seen with an underbite too. For them, it’s a cute breed trait that doesn’t typically cause them much harm. They have more trouble breathing than they do biting and chewing. Most dogs that have these flattened facial features and smushed-in noses are the ones with an underbite. Pugs are bred to have these facial features, and thus they have underbites.

Undershot is a class III malocclusion that is also referred to as mandibular prognathism, maxillary brachygnathism, mandibular mesioclusion, or an underbite. This malocclusion is characterized by a shorter upper jaw and a longer lower jaw, resulting in lower teeth that are in front of the upper teeth. While this condition is normal for some breeds, such as Bulldogs, in many breeds it is unusual. An undershot jaw occurs when the lower jaw grows faster than normal and becomes longer than the upper jaw, and is usually evident around 8 weeks of age in puppies. This misalignment can cause soft tissue trauma, such as to the lips. When the incisors meet instead of fitting next to each other, it is called a level bite. When the malocclusion causes the lower incisors to be placed in front of the upper incisors, it is called a reverse scissors bite.

The cause of overshot and undershot jaws in dogs relate to the increased or decreased rate of growth of the upper and lower jaws in relation to one another. This can occur due to a: Genetic disorder Trauma; Systemic infection ;Nutritional disorder; Endocrine disorder; Abnormal setting of puppy teeth; Early or late loss of puppy teeth.

After a quick physical exam, your vet may have to sedate your dog in order to perform a thorough oral exam. This will assess your dog’s skull type and teeth location in relation to the teeth on the opposite jaw. Often, the placement of the upper and lower incisors in relation to one another can determine what type of malocclusion your dog has. Your vet will note any areas of trauma due to teeth striking those areas, and any cysts, tumors, abscesses, or remaining puppy teeth that may be present. A dental X-ray can also help to assess the health of the jaws and teeth. These diagnostic methods will lead to a diagnosis of an overshot or undershot jaw in your dog.

Treatment of a jaw misalignment will depend on the severity of the condition. If your dog has a misalignment, but can still bite and chew food without problems, no treatment may be needed. If the misalignment is caught early in a puppy’s life, it may only be temporary and may correct itself over time. However, there are times when intervention may be needed. If your puppy’s teeth are stopping the normal growth of his jaws, then surgery to remove those puppy teeth may be performed. This may allow the jaws to continue to grow, but will not make them grow. For older dogs who are experiencing pain and trauma due to misaligned jaws and teeth, oral surgery is generally performed to extract teeth that are causing trauma, to move teeth so that they fit, or to create space for a misaligned tooth to occupy. Other therapies include crown reductions or braces.

If your dog is genetically programmed to have an overshot or undershot jaw, intervention can help, but will not slow or stop the abnormal growth of either jaw. Prevent jaw misalignments in puppies by not breeding dogs who have overshot or undershot jaws.

Aussie Times editor’s note: This letter was written to Linda Boysal from Liz DeHaven about some old-time Aussie-type dogs in Oregon.  Thank you, Linda, for sharing it with us.

I had a couple of pictures made for you.  These are of “Cindy” (I’m sure Alan told you about her.)  She was one of the best two dogs in world.  The other was her litter sister, “Fiddle” (mine.)  These were “Scotch Shepherds.”  We feel this is the origin of the breed and that they were Scotch Shepherds before they went to Australia and became “Australian Shepherds.”

There are (or were) quite a few sheepmen in Oregon of Scotch descent, some second generation and most of them had these “Scotch Shepherd,” always black with white markings.  When they began to register Border Collies, at least in our area (coast) everything with black hair and white markings suddenly became registered “Border Collies.”  I know for a fact of sheepmen who had Scotch Shepherds one year and the same dogs were registered Border Collies the next.  By now, of course, they have become a mixed breed, we feel the worse for both.  Notice the difference in working style of imported Border Collies and domestic ones.

After reading the standard of the Kelpie in the National Stock Dog magazine, I feel that the original Border Collies were of the stock of the North County or Fox Collies described in that article, winter 1972-1973.

1.  The working style.  The little sheep dog of Californie, used by the Basque and Portuguese sheepherders and to be found on most every ranch with big herding problems, was usually a prick eared, short legged dog.  They were born, not trained. to that famous ducking style of action.  Head down as they ran, almost a slink or a glide, duck, glide and stare or eyeball the sheep.  They were uncanny in working sheep, but worse than useless on cows.

There was an old Scotch lady in Oregon.  She was in her 80’s in 1950 and had some famous dogs.  The story goes that her father had brought them from Scotland at least that long ago and no one could get one unless he managed to steal it.  For 50 years she had allowed no new blood into the strain, breeding mother to son, father to daughter, only when she needed a replacement.  She would choose the one she wanted and then destroy the rest of the litter.  When she was this age, she was ailing and had to move to town.  She had a manager living on her ranch caring for about 500 sheep and what looked like millions of turkeys.  She had bred her pair of dogs and picked the male for the next generation and ordered him to kill the rest of the pups.  Instead, he gave one to a friend of his, who helped up to get ours.  We went up to see him and he had the two little females left.  He gave them both to us,  after we swore we would never tell anyone where we got them as long as the old lady was alive.  We never did.  He said she would fire him, at least, but he couldn’t bring himself to kill them.

Those are the good dogs we have had since we were married.  Alan’s family had Australian Shepherds and Scotch Shepherds before he was born.  The question of size comes up all of the time.  He thinks they were just strains as in any livestock.  If they wanted them for cow dogs, they bred them bigger and long legged (to keep up with horses.)  For sheep they went toward the small ones.  They would have to pick up and change dogs on long, hot drives as they tired or became sore-footed, etc.  Herders who rode horses would sometimes carry their dog on the horse to rest it.

All of his life.  He went to the mountains with the sheep when he was 6 weeks old or so.  On a pack mule.  His parents had a string of pack mules, 18, I think and packed into the summer range, kids, dogs, herders and all.

Pretty well answered that.  Raised sheep and/or cattle until fourteen years ago.  Raised purebred dairy goats for hobby.  Not much need to use dogs there.  But did sometimes.

They raised calves on the goat mill to get their project started, and would have forty or so at one time.  Raise them and turn them out on the range which was cut over timber land.  Later, they sold the goat mile to a cheese factory.  To watch those dogs work was a real treat!

Rex had taught himself to be a seeing-eye dog.  No one know how he knew Mr. Hogan was blind.  Mr. Hogan milked the goats by machine.  Rex would bring them up to the milking stand, 4 at a time.  When no more came, Mr. Hogan would say, “Is that all?”  Rex would go smell their udders, that way he could tell if they had been milked.  If there were no more, he would bark one bark.  Then Mr. Hogan would open the door and the goats would go out.  As the last one went out the door, Rex would go under Mr. Hogan’s hand to show, that’s all.  Between the “sets” of milkers, he would bring the kids up to the stanchions to be fastened in and fed their milk and the calves on the other side.

The first one Alan remembers is Bob.  Alan was about 4 yrs. old.  Bob was the leggy type and an excellent sheep dog.  He had a pronounced overshot jaw.

Rip was reddish brown merle with white chest, natural bob tail.  He can’t remember the eye color of either.  Rip was a cow dog, a great heeler and wicked dog fighter.  He was the short coupled type (as compared to leggy.)

His uncle Ollie DeHaven, sheepman, had a strain of black with white rings, no tan, natural bob tailed, leggy type.  Had them until his death.  If anyone asked Uncle Ollie what kind of dogs they were, he said, “Damn good ones, friend!”  None of that family believed in registering working dogs!

There you have it.  It seems they bred the blues to blues (and no one heard of blind or deaf ones) and the blacks to blacks and if an off color came, they asked, “Is it smart or can it bite a cow?”  One of the best sheepdogs I ever saw (1939) was a snow white Australian Shepherd, with one black ear.  No, he was not deaf or blind!

The culling was simple.  Not by how the tail set or ears hung.  The good ones lived and they had to be good as so much depended on them.  Alan’s mother used to laugh about his Dad culling dogs.  Said he had about twenty one time and two of them were  what he considered good.  So, he just shot them all but the two, Skunks and Flora, and started over.

Enzo is a short-haired Havanese and he was born with his lower jaw shorter than the upper jaw. This is called an Overbite, also referred to as an Overshot Jaw, a Parrot Mouth or Mandibular Brachygnathism. This malocclusion is a genetic change and can be seen in a number of breeds, oftentimes collie related breeds and dachshunds. Occasionally this change happens because of differences in the growth of the upper and lower jaws, and in many cases it doesn’t cause any significant problems other than cosmetically.

Dr. Robin Riedinger evaluated Enzo at his first visit when he was just 11 weeks of age and while the lower jaw was too short, there was no evidence of damage and no indication that this was causing a problem for Enzo. When there is abnormal occlusion of the teeth, it is important to monitor closely for trouble caused by the teeth being aligned improperly. Malocclusions can lead to gum injuries, puncturing of the hard palate, abnormal positioning of adjacent teeth, abnormal wear and bruising of the teeth, permanent damage and subsequent death of one or more teeth, and in the long run, premature loss of teeth. Some malocclusions can be severe enough to interfere with normal eating and drinking.

Within three weeks, when Enzo was only 3.5 months old, it was clear that our doctors would need to intervene. The left and right sides of Enzo’s upper jaw (maxilla) were growing at different rates because the lower canine teeth were being trapped by the upper canine teeth. This is called Dental Interlock. Because the teeth are ‘locked’ in place, the lower jaw cannot grow symmetrically and this creates a number of other problems. Early intervention is critical.

The solution for Dental Interlock is to extract the teeth from the shorter jaw; in this case, the lower ‘baby’ canines and thereby allow the lower jaw (mandible) to grow in the best way possible. This procedure is most effective when the Dental Interlock is discovered early and the extractions are performed quickly. In some cases, this can be as early as ten weeks of age. Dr. Riedinger consulted with a local veterinary dental specialist to confirm the treatment plan and to get advice on extracting the deciduous teeth without damaging the developing adult canines. Dental radiographs are essential to proper extraction technique and also to ensure that there are no other abnormalities below the gumline.

Once extracted, each deciduous canine tooth was about 2 centimeters long; the roots were about 1.5 centimeters. Many people are surprised to learn that the root of a dog’s tooth is so large – 2/3 to 3/4 of the tooth is below the gumline. This is one reason why it is so important to use radiographs to evaluate teeth on a regular basis, not just in a growing puppy. Adult teeth can, and frequently do, have problems that are only visible with a radiograph.

Enzo came through his procedure extremely well. He was given pain medications for comfort and had to eat canned foods and avoid chewing on his toys for the next two weeks to ensure that the gum tissue healed properly. As he continues to grow we will be monitoring how his jaw develops and Dr. Riedinger will also be watching the alignment of his adult canine teeth when they start to emerge around six months of age. Hopefully this early intervention will minimize problems for Enzo in the future.

The Romans were known to use waterwheels extensively in mining projects, with enormous Roman-era waterwheels found in places like modern-day Spain. They were reverse overshot water-wheels designed for dewatering mines. A series of overshot mills existed at Barbegal near Arles in southern France where corn was milled for the production of bread. The Roman poet Ausonius mentions a mill for cutting marble on the Moselle. Floating mills were also known from the later Empire, where a wheel was attached to a boat moored in a fast flowing river.

Most water wheels in the United Kingdom and the United States are (or were) vertical wheels rotating about a horizontal axle, but in the Scottish highlands and parts of southern Europe mills often had a horizontal wheel (with a vertical axle). Water wheels are classified by the way in which water is applied to the wheel, relative to the wheel"s axle. Overshot & pitchback waterwheels are suitable where there is a small stream with a height difference of more than 2 meters, often in association with a small reservoir. Breastshot and undershot wheels can be used on rivers or high volume flows with large reservoirs.

Breastshot wheels are less efficient than overshot wheels (see below), more efficient than undershot wheels, and are not backshot (see below). The individual blades of a breastshot wheel are actually buckets, as are those of most overshot wheels, and not simple paddles like those of most undershot wheels. A breastshot wheel requires a good trash rake and typically has a masonry "apron" closely conforming to the wheel face, which helps contain the water in the buckets as they progress downwards. Breastshot wheels are preferred for steady, high-volume flows such as are found on the fall line of the North American East Coast.

A vertically-mounted water wheel that is rotated by falling water striking paddles, blades or buckets near the top of the wheel is said to be overshot. In true overshot wheels the water passes over the top of the wheel, but the term is sometimes applied to backshot or pitchback wheels where the water goes down behind the waterwheel.

A typical overshot wheel has the water channeled to the wheel at the top and slightly beyond the axle. The water collects in the buckets on that side of the wheel, making it heavier than the other "empty" side. The weight turns the wheel, and the water flows out into the tail-water when the wheel rotates enough to invert the buckets. The overshot design can use all of the water flow for power (unless there is a leak) and does not require rapid flow.

Unlike undershot wheels, overshot wheels gain a double advantage from gravity. Not only is the force of the flowing water partially transferred to the wheel, the weight of the water descending in the wheel"s buckets also imparts additional energy. The mechanical power derived from an overshot wheel is determined by the wheel"s physical size and the available head, so they are ideally suited to hilly or mountainous country. On average, the undershot wheel uses 22 percent of the energy in the flow of water, while an overshot wheel uses 63 percent, as calculated by English civil engineer John Smeaton in the 18th century.

Overshot wheels demand exact engineering and significant head, which usually means significant investment in constructing a dam, millpond and waterways. Sometimes the final approach of the water to the wheel is along a lengthy flume or penstock.

A backshot wheel (also called pitchback) is a variety of overshot wheel where the water is introduced just behind the summit of the wheel. It combines the advantages from breastshot and overshot systems, since the full amount of the potential energy released by the falling water is harnessed as the water descends the back of the wheel.

A backshot wheel continues to function until the water in the wheel pit rises well above the height of the axle, when any other overshot wheel will be stopped or even destroyed. This makes the technique particularly suitable for streams that experience extreme seasonal variations in flow, and reduces the need for complex sluice and tail race configurations. A backshot wheel may also gain power from the water"s current past the bottom of the wheel, and not just the weight of the water falling in the wheel"s buckets.

Overshot (and particularly backshot) wheels are the most efficient type; a backshot steel wheel can be more efficient (about 60%) than all but the most advanced and well-constructed turbines. Nevertheless, in some situations an overshot wheel is preferable to a turbine.

Traditionally water wheels have been made mostly from wood. Steel in overshot (and pitchback) wheels allows higher speeds. A wooden wheel with a wooden axle cannot necessarily sustain high speed needed for hydroelectric power generation.

Here is a visual look into what an “undershot” and “overshot” jaw looks like. In recent years, I’ve noticed more and more dogs with this issue. Can a dog live productive life with a malocclusion: (imperfect positioning of the teeth when a jaws closed) Yes but with some issues along the way.

Let’s begin with a puppy will have 28 “puppy teeth” by the time it reaches six months old (this number can vary from breed to breed) By adulthood, most breeds will have a total of 42 teeth. As defined above a malocclusion or simply a misalignment of a dog’s teeth occurs when their bite does not fit accordingly beginning as puppy’s teeth come in and worsening as their adult teeth follow.

the upper jaw is longer than the lower one, an overshot or overbite. When a dogs mouth is closed, a gap between the upper and lower incisors (teeth) will be present. In most cases, puppies are born with a slight over/under bite and with time the problem can correct itself if the gap is not too large. What should be noted is if a dog’s bite remains over/undershot by 8-10 months old, that’s how it will remain for the remainder of its life. In overbite’s the structure may worsen as the permanent teeth come in as they are larger and can damage the soft parts of the mouth. Teeth extractions are sometimes necessary.

Structural dentition of a puppies jaw should be checked very early on to help eliminate this issue. Unfortunately most dog owners won’t notice until is late in the game. More so is the issues of backyard and/or inexplicable breeders breeding dogs with undershot/overshot jaws and potentially passing along this trait to future generations.

With an overbite, the upper jaw is longer than the lower one. When the mouth is closed, a gap between the upper and lower incisors occurs. Puppies born with an overbite will sometimes have the problem correct itself if the gap is not too large. However, a dog’s bite will usually set at ten months old. At this time improvement will not happen on its own. Your pet’s overbite may worsen as the permanent teeth come in because they are larger and can damage the soft parts of the mouth. Teeth extractions are sometimes necessary.

Problems that can arise from malocclusion are; difficulty chewing, picking up food and other objects, dogs with overshot jaws tend to pick up larger chunks of food since they can’t chew nor pick up smaller morsels which can lead to choking and future intestinal issues. These dogs are also prone to tartar and plaque build up which if left untreated can lead to other significant health issues such as heart problems. Other issues are listed below:

What’s important to note is that most malocclusions do not require treatment, it’s simply how a dog will live its full life as. This is important since most breeders breeding for financial gains don’t think about. What can be done is to brush the teeth regularly to prevent abnormal build-up of tartar and plaque. A veterinarian in cases that can be solved will sometimes recommend a dental specialist if a client want to correct the teeth misalignment. Recently I’ve heard o specialist putting “braces” on puppies to realign the teeth.

#dog #dogs #puppy #pup #puppies #puppylove #pets #life #family #bulldog #maltese #mastiff #chihuahua #cockerspaniel #vet #meds #instadog #instagood #instadaily