puppy overshot jaw free sample

You can download this article on puppy teeth problems as an ebook free of charge (and no email required) through the link below. This comprehensive article covers such topics as malocclusions, overbites, underbites and base narrow canines in dogs. Special emphasis is placed on early intervention – a simple procedure such as removing retained puppy teeth can save many problems later on.

The ‘carnassial’ teeth are the large specialised pair of teeth towards the back of the mouth on each side, which work together like the blades of a pair of scissors. The upper carnassial is the fourth premolar, while the lower one is the first molar The upper jaw is the maxilla, and the lower jaw is the mandible.

Malocclusion is the termed used for an abnormal bite. This can arise when there are abnormalities in tooth position, jaw length, or both. The simplest form of malocclusion is when there are rotated or crowded teeth. These are most frequently seen in breeds with shortened muzzles, where 42 teeth need to be squeezed into their relatively smaller jaws. Affected teeth are prone to periodontal disease (inflammation of the tissues supporting the teeth, including the gums and jawbone), and early tooth loss.

Class II malocclusions (‘overshot’) arise when the lower jaw is relatively short compared with the upper jaw. This type of occlusion is NEVER considered normal and can result in significant and painful trauma to the upper gums, hard palate and teeth from the lower canines and incisors.

Class III malocclusions (‘undershot’, ‘prognathism’) occur when the lower jaw is relatively long compared with the upper jaw. The upper incisors may either meet the lower ones (level bite) or sit behind them (reverse scissor bite). While this is very common, and considered normal for some breeds, it can cause problems if the upper incisors are hitting the floor of the mouth or the lower teeth (similar problems to rostral crossbite). If the lower canines are striking the upper incisors, the accelerated dental wear often results in dead or broken teeth.

Class IV malocclusions (‘wry bite’) occur when there is a deviation of one or both jaws in any direction (up and down, side to side or front to back). These may be associated with mild to severe problems with chewing, damage to teeth and oral tissues, and chronic pain.

Normal development of the teeth and jaws is largely under genetic control, however environmental forces such as nutrition, trauma, dental interlock and other mechanical forces can also affect the final outcome.

Most malocclusions involving jaw length (skeletal) abnormalities are genetic in origin. We need to recognise this as it has enormous implications if you are planning to breed, as once a malocclusion is established in a line, it can be heartbreaking work to try and breed it back out.

The exact genes involved in jaw development are not yet well understood. We do know that the upper and lower jaws grow at different rates, at different times, and are under separate genetic control. In fact, the growth of one only affects the growth of the other if there is physical contact between them via the teeth. This contact is called ‘dental interlock’.

When the upper and lower teeth are locked against each other, the independent growth of either jaw is severely limited. This can occasionally work in the dog’s favour, for example if the lower jaw is slightly long compared with the upper jaw, the corner incisors may lock the lower canines in position behind them, limiting any further growth spurts of the lower jaw.

However, in many cases, dental interlock interferes with jaw development in a negative way. A classic example we see regularly in our practice is when a young puppy has a class II malocclusion (relatively short lower jaw) and the lower deciduous canines are locked behind the upper deciduous canines, or trapped in the tissues of the hard palate. In these cases, even if the lower jaw was genetically programmed to catch up to the upper jaw, it cannot physically do so.

Extraction of these teeth will not stimulate jaw growth, but will allow it to occur if nature (ie genetic potential) permits. It also relieves the painful trauma caused by the teeth to the hard palate whenever the pup closes its mouth (and we all know how sharp those baby teeth are!!). More information on interceptive orthodontics can be found later in this book.

It is crucial to remember that genetic malocclusions are not usually seen in all puppies in an affected litter as they are not dominant traits. Puppies can carry the genes contributing to genetic faults without showing any physical signs at all. If an affected puppy is noted, extreme caution should be exerted when planning future breeding from the parents and siblings, and neutering of the affected puppy is strongly recommended.

Although diet often gets the blame for development of malocclusions, the role of nutrition is actually much less significant than is often believed. Obviously gross dietary deficiencies will affect bone and tooth development, for example severe calcium deficiency can lead to ‘rubber jaw’. However, the vast majority of puppies are on balanced, complete diets and have adequate nutrient intake for normal bone and tooth development.

One myth I have heard repeated by several owners is that strict limitation of a puppy’s dietary intake can be used to correct an undershot jaw. This is simply NOT true. Limiting calories will NOT slow the growth of the lower jaw relative to the upper jaw (both jaws receive the same nutrient supply). Such a practice is not only ineffective, it can be detrimental for the puppy’s overall growth and development.

Trauma, infection and other mechanical forces may affect growth and development of the jaws and teeth. Developing tooth buds are highly sensitive to inflammation and infection, and malformed teeth may erupt into abnormal positions (or not erupt at all!). Damage to developing teeth can also occur if the jaw is fractured.

Retained or persistent deciduous (puppy) teeth can also cause malocclusions by forcing the erupting adult teeth into an abnormal position. As previously mentioned, this may be a genetic trait, but can also occur sporadically in any breed of dog.

A full bite assessment can help differentiate between malocclusions which are due to shifting of teeth alone, and those which have an underlying genetic basis. Contact me if you would like to arrange a bite assessment for your puppy

Extraction of lower canine teeth – the roots of these teeth make up about 70% of the front of the jaw, and so there is a potential risk of jaw fracture associated with their removal. Some dogs also use these teeth to keep the tongue in position, so the tongue may hang out after extraction. ‡

This is the term we use when we remove deciduous teeth to alter the development of a malocclusion. The most common form of this is when we relieve dental interlock that is restricting normal jaw development. Such intervention does not make the jaw grow faster, but will allow it to develop to its genetic potential by removing the mechanical obstruction.

Extraction of deciduous lower canines and incisors in a puppy with an overbite releases the dental interlock and gives the lower jaw the time to ‘catch up’ (if genetically possible).

As jaw growth is rapid in the first few months of life, it is critical to have any issues assessed and addressed as soon as they are noticed, to give the most time for any potential corrective growth to occur before the adult teeth erupt and dental interlock potentially redevelops. Ideally treatment is performed from eight weeks of age.

Extraction of deciduous teeth is not necessarily as easy as many people imagine. These teeth are very thin-walled and fragile, with long narrow roots extending deep into the jaw. The developing adult tooth bud is sitting right near the root, and can be easily damaged. High detail intraoral (dental) xrays can help us locate these tooth buds, so we can reduce the risk of permanent trauma to them. Under no circumstances should these teeth be snapped or clipped off as this is not only inhumane, but likely to cause serious infection and ongoing problems below the surface.

Sometimes a puppy may be missing one or more teeth. In the absence of trauma (which is usually apparent for other reasons!), there are a couple of things that may be going on.

Sometimes, the tooth will be in a favourable position but caught behind a small rim of jawbone – again early surgical intervention may be successful in relieving this obstruction. If the tooth is in an abnormal position or deformed, it may be unable to erupt even with timely surgery.

Impacted or embedded teeth should be removed if they are unable to erupt with assistance. If left in the jaw, a dentigerous cyst may form around the tooth. These can be very destructive as they expand and destroy the jawbone and surrounding teeth. Occasionally these cysts may also undergo malignant transformation (ie develop into cancer).

Firstly, if there are two teeth in one socket (deciduous and adult), the surrounding gum cannot form a proper seal between these teeth, leaving a leaky pathway for oral bacteria to spread straight down the roots of the teeth into the jawbone. Trapping of plaque, food and debris between the teeth also promotes accelerated periodontal disease. This not only causes discomfort and puts the adult tooth at risk of early loss, but allows infection to enter the bloodstream and affect the rest of the body.

Puppies play rough, chew whatever they can get hold of, and have tiny teeth with very thin walls. Therefore fractures will sometimes occur. A common misconception is that broken deciduous teeth can be left until they fall out. Unfortunately this is NOT true. From the puppy’s point of view, broken teeth HURT, just as they do in children. Anyone who has had a bad toothache would agree that even a few weeks is a long time to wait for relief!

Broken teeth also become infected, with bacteria from the mouth gaining free passage through the exposed pulp chamber inside the tooth, deep into the underlying jawbone. This is not only painful, but can lead to irreversible damage to the developing adult tooth bud, which may range from defects in the enamel (discoloured patches on the tooth) through to arrested development and inability to erupt. The infection can also spread through the bloodstream to the rest of the body. Waiting for the teeth to fall out is NOT a good option!

You can use this royalty-free photo "Small dog with undershot jaw posing indoors" for personal and commercial purposes according to the Standard or Extended License. The Standard License covers most use cases, including advertising, UI designs, and product packaging, and allows up to 500,000 print copies. The Extended License permits all use cases under the Standard License with unlimited print rights and allows you to use the downloaded stock images for merchandise, product resale, or free distribution.

You can use this royalty-free photo "Black and tan mixed breed dog with undershot jaw" for personal and commercial purposes according to the Standard or Extended License. The Standard License covers most use cases, including advertising, UI designs, and product packaging, and allows up to 500,000 print copies. The Extended License permits all use cases under the Standard License with unlimited print rights and allows you to use the downloaded stock images for merchandise, product resale, or free distribution.

Occlusion is defined as the relationship between the teeth of the maxilla (upper jaw) and mandibles (lower jaw). When this relationship is abnormal a malocclusion results and is also called an abnormal bite or an overbite in dogs and cats.

Hounds: The Otterhound might be known for his shaggy coat and webbed feet, but his bite is certainly the most unique among hound breeds: The jaws are powerful and capable of a crushing grip.

Terriers: Despite his dandelion coif and saucer eyes, the Dandie Dinmont Terrier is equipped with a set of teeth capable of hunting badgers. The standard spares no words in describing both bite and number of teeth: The teeth meet in a tight scissors bite. The teeth are very strong, especially the canines, which are an extraordinary size for a small dog. The canines mesh well with each other to give great holding and punishing power. The incisors in each jaw are evenly spaced and six in number.

Non-Sporting: The Bulldog’s bite is among the breed’s signature features, and the standard is precise in its description: The jaws should be massive, very broad, square and “undershot,” the lower jaw projecting considerably in front of the upper jaw and turning up. … The teeth should be large and strong, with the canine teeth or tusks wide apart, and the six small teeth in front, between the canines, in an even, level row.

There was no much attention paid until now to bite and teeth quality of Louisiana Catahoula. The reason is that Catahoula is the American breed and there is generally only a little attention focused on this matter. Both NALC standard, valid since 1977 (last revision in 1994) and UKC standard (2008) say that: „A scissors bite is preferred, but a level bite is acceptable. Full dentition is greatly desired, but dogs are not to be penalized for worn or broken teeth. Overshot or undershot bite are serious faults, but not disqualifying“. Catahoula is working breed and working qualities have been always more demanded than an ideal conformation and a superior bite. This is also the heritage we must deal with now.

Evaluation of European breeds and breeding was always more strict in this point of view and more focused on correct bite and full dentition, namely in breeds that preserve more or less normal skull parameters. Thus, scissor bite and full dentition is what most of breed standards demand and faults are more penalized. There is a good reason for it, because an efficient function needs a proper skull and jaw structure and teeth position. However, some anomalies were found also in wild living wolves and some faults are fairly common among various dog breeds even if not wanted.

Full dentition with all adult teeth fully erupted consist of incisors (Incisives – I), canines (Caninus – C), premolars (Praemolares – P), and molares (Molares – M). Upper and lower jaw differ in a number of molars. The teeth pattern is following:

In training and performing Schutzhund the preferred grip is a „full mouth bite“. The dog should grasp subject’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 and their overlapping structure combined with jaw strength prevents the prey from pulling free. Once the prey is down, the premolars are used for biting off chunk of meat. The upper P4 and the lower M1 on each side are especially developed for this task. The carnasals 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. The incisors located at the front of the mouth are specialized for delicate work. They nibble the last bits of meat off bones and are also handy for scratching an itch or pulling something bothersome out of the coat or from between the pads. Molars, other than mentioned, are flat for grinding plant matter. Wolves eat also some fruits, grasses and other plant matter and this type of food must be chewed a little to start digestive process.

All those specialized teeth have their proper position in the jaw, which 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. Jaw strength comes not only from the muscles, but the shape of the skull (1).

Research among wild wolves showed that the most frequent anomaly was the absence of the last molar in the lower jaw, M3. As it does not change the function, the absence of M3 should not be considered breeding deficiency also in dogs (2).

Faults of bite concern also Catahoula breed. Dog’s bite is the way his teeth fit when his upper and lower jaws are closed. The standard type is a scissor bite, in which the upper incisors just overlap and touch the lower incisors and all premolars and molars fully fit. Another possible variation is a tight scissor bite, when upper and lower incisors touch each other more then above or lower incisors are outwards of longitudinal line of bottom jaw. Catahoula has also a level (even) bite permitted by the breed standard. It is when the upper and lower incisors meet exactly, surface to surface. This means that teeth can be worn down much faster, but it does not affect actually the function and both jaws are of the same length as in previous cases. Level bite is considered normal in some breeds, including Catahoula, nevertheless,  some consider this type of bite as an expression of underbite. On the other hand, research among wild wolves showed that fully a third of animals 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.

Undershot bite is when the upper jaw is perceptibly shorter than the lower jaw and the lower incisors are located in front of the upper ones. This is typical for some breeds such as Boxer, Bulldog, Pug, Pekinese, etc. that have a shorter foreface and longer lower jaw.

Overshot bite is caused by physically longer upper jaw than the lower one and the uneveness between them is larger than 2 mm. This fault occurs more often among dog breeds nowadays. Contrary to undershot, this fault can be controlled by genetics, nutrition, environment and by mechanical forces generated by the interlock of the upper and lower teeth. Overshot  can affect the mouth’s function more than undershot and indicates usually weakness in the lower jaw.

The incidence of level bites is increasing among Catahoulas beside some missing teeth. Undershot bite is one of more serious faults that occur in this breed. There is no doubt that such faults and abnormalities are inherited. Upper and lower jaws grow independently, factors influencing a size of jaw are different from those affecting the size of teeth and various genes are involved in this process. These problems are polygenic resulting from the action of many genes, thus it is difficult to eliminate them because there is no single „bad bite“ gene.  The length of the skull and the muzzle play a role and a dominant way of a shorter skull inheritance is known. Thus, this must be taken into account in case of Catahoula, too. A combination of parents with rather different length of their muzzles is not recommended, because it could increase the incidence of faults in bites and occurrence of undershot or overshot bites among offsprings. And we have proved already that Catahoulas may vary in their muzzle size in more than one third of its length.

Inheritance and elimination of severe dental faults is difficult in breeds more numerous than Catahoula. There is impossible to exclude from breeding all individuals that show any fault due to complicated, polygenic and often recessive way of inheritance in such a rare breed. However, those showing more serious faults, such as the overshot and the undershot bite and numerous and the most important teeth missing, should be surely excluded from breeding.

There was no much attention paid until now to bite and teeth quality of Louisiana Catahoula. The reason is that Catahoula is the American breed and there is generally only a little attention focused on this matter. Both NALC standard, valid since 1977 (last revision in 1994) and UKC standard (2008) say that: „A scissors bite is preferred, but a level bite is acceptable. Full dentition is greatly desired, but dogs are not to be penalized for worn or broken teeth. Overshot or undershot bite are serious faults, but not disqualifying“. Catahoula is working breed and working qualities have been always more demanded than an ideal conformation and a superior bite. This is also the heritage we must deal with now.

Evaluation of European breeds and breeding was always more strict in this point of view and more focused on correct bite and full dentition, namely in breeds that preserve more or less normal skull parameters. Thus, scissor bite and full dentition is what most of breed standards demand and faults are more penalized. There is a good reason for it, because an efficient function needs a proper skull and jaw structure and teeth position. However, some anomalies were found also in wild living wolves and some faults are fairly common among various dog breeds even if not wanted.

Full dentition with all adult teeth fully erupted consist of incisors (Incisives – I), canines (Caninus – C), premolars (Praemolares – P), and molares (Molares – M). Upper and lower jaw differ in a number of molars. The teeth pattern is following:

In training and performing Schutzhund the preferred grip is a „full mouth bite“. The dog should grasp subject’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 and their overlapping structure combined with jaw strength prevents the prey from pulling free. Once the prey is down, the premolars are used for biting off chunk of meat. The upper P4 and the lower M1 on each side are especially developed for this task. The carnasals 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. The incisors located at the front of the mouth are specialized for delicate work. They nibble the last bits of meat off bones and are also handy for scratching an itch or pulling something bothersome out of the coat or from between the pads. Molars, other than mentioned, are flat for grinding plant matter. Wolves eat also some fruits, grasses and other plant matter and this type of food must be chewed a little to start digestive process.

All those specialized teeth have their proper position in the jaw, which 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. Jaw strength comes not only from the muscles, but the shape of the skull (1).

Research among wild wolves showed that the most frequent anomaly was the absence of the last molar in the lower jaw, M3. As it does not change the function, the absence of M3 should not be considered breeding deficiency also in dogs (2).

Faults of bite concern also Catahoula breed. Dog’s bite is the way his teeth fit when his upper and lower jaws are closed. The standard type is a scissor bite, in which the upper incisors just overlap and touch the lower incisors and all premolars and molars fully fit. Another possible variation is a tight scissor bite, when upper and lower incisors touch each other more then above or lower incisors are outwards of longitudinal line of bottom jaw. Catahoula has also a level (even) bite permitted by the breed standard. It is when the upper and lower incisors meet exactly, surface to surface. This means that teeth can be worn down much faster, but it does not affect actually the function and both jaws are of the same length as in previous cases. Level bite is considered normal in some breeds, including Catahoula, nevertheless,  some consider this type of bite as an expression of underbite. On the other hand, research among wild wolves showed that fully a third of animals 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.

Undershot bite is when the upper jaw is perceptibly shorter than the lower jaw and the lower incisors are located in front of the upper ones. This is typical for some breeds such as Boxer, Bulldog, Pug, Pekinese, etc. that have a shorter foreface and longer lower jaw.

Overshot bite is caused by physically longer upper jaw than the lower one and the uneveness between them is larger than 2 mm. This fault occurs more often among dog breeds nowadays. Contrary to undershot, this fault can be controlled by genetics, nutrition, environment and by mechanical forces generated by the interlock of the upper and lower teeth. Overshot  can affect the mouth’s function more than undershot and indicates usually weakness in the lower jaw.

The incidence of level bites is increasing among Catahoulas beside some missing teeth. Undershot bite is one of more serious faults that occur in this breed. There is no doubt that such faults and abnormalities are inherited. Upper and lower jaws grow independently, factors influencing a size of jaw are different from those affecting the size of teeth and various genes are involved in this process. These problems are polygenic resulting from the action of many genes, thus it is difficult to eliminate them because there is no single „bad bite“ gene.  The length of the skull and the muzzle play a role and a dominant way of a shorter skull inheritance is known. Thus, this must be taken into account in case of Catahoula, too. A combination of parents with rather different length of their muzzles is not recommended, because it could increase the incidence of faults in bites and occurrence of undershot or overshot bites among offsprings. And we have proved already that Catahoulas may vary in their muzzle size in more than one third of its length.

Inheritance and elimination of severe dental faults is difficult in breeds more numerous than Catahoula. There is impossible to exclude from breeding all individuals that show any fault due to complicated, polygenic and often recessive way of inheritance in such a rare breed. However, those showing more serious faults, such as the overshot and the undershot bite and numerous and the most important teeth missing, should be surely excluded from breeding.

There was no much attention paid until now to bite and teeth quality of Louisiana Catahoula. The reason is that Catahoula is the American breed and there is generally only a little attention focused on this matter. Both NALC standard, valid since 1977 (last revision in 1994) and UKC standard (2008) say that: „A scissors bite is preferred, but a level bite is acceptable. Full dentition is greatly desired, but dogs are not to be penalized for worn or broken teeth. Overshot or undershot bite are serious faults, but not disqualifying“. Catahoula is working breed and working qualities have been always more demanded than an ideal conformation and a superior bite. This is also the heritage we must deal with now.

Evaluation of European breeds and breeding was always more strict in this point of view and more focused on correct bite and full dentition, namely in breeds that preserve more or less normal skull parameters. Thus, scissor bite and full dentition is what most of breed standards demand and faults are more penalized. There is a good reason for it, because an efficient function needs a proper skull and jaw structure and teeth position. However, some anomalies were found also in wild living wolves and some faults are fairly common among various dog breeds even if not wanted.

Full dentition with all adult teeth fully erupted consist of incisors (Incisives – I), canines (Caninus – C), premolars (Praemolares – P), and molares (Molares – M). Upper and lower jaw differ in a number of molars. The teeth pattern is following:

In training and performing Schutzhund the preferred grip is a „full mouth bite“. The dog should grasp subject’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 and their overlapping structure combined with jaw strength prevents the prey from pulling free. Once the prey is down, the premolars are used for biting off chunk of meat. The upper P4 and the lower M1 on each side are especially developed for this task. The carnasals 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. The incisors located at the front of the mouth are specialized for delicate work. They nibble the last bits of meat off bones and are also handy for scratching an itch or pulling something bothersome out of the coat or from between the pads. Molars, other than mentioned, are flat for grinding plant matter. Wolves eat also some fruits, grasses and other plant matter and this type of food must be chewed a little to start digestive process.

All those specialized teeth have their proper position in the jaw, which 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. Jaw strength comes not only from the muscles, but the shape of the skull (1).

Research among wild wolves showed that the most frequent anomaly was the absence of the last molar in the lower jaw, M3. As it does not change the function, the absence of M3 should not be considered breeding deficiency also in dogs (2).

Faults of bite concern also Catahoula breed. Dog’s bite is the way his teeth fit when his upper and lower jaws are closed. The standard type is a scissor bite, in which the upper incisors just overlap and touch the lower incisors and all premolars and molars fully fit. Another possible variation is a tight scissor bite, when upper and lower incisors touch each other more then above or lower incisors are outwards of longitudinal line of bottom jaw. Catahoula has also a level (even) bite permitted by the breed standard. It is when the upper and lower incisors meet exactly, surface to surface. This means that teeth can be worn down much faster, but it does not affect actually the function and both jaws are of the same length as in previous cases. Level bite is considered normal in some breeds, including Catahoula, nevertheless,  some consider this type of bite as an expression of underbite. On the other hand, research among wild wolves showed that fully a third of animals 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.

Undershot bite is when the upper jaw is perceptibly shorter than the lower jaw and the lower incisors are located in front of the upper ones. This is typical for some breeds such as Boxer, Bulldog, Pug, Pekinese, etc. that have a shorter foreface and longer lower jaw.

Overshot bite is caused by physically longer upper jaw than the lower one and the uneveness between them is larger than 2 mm. This fault occurs more often among dog breeds nowadays. Contrary to undershot, this fault can be controlled by genetics, nutrition, environment and by mechanical forces generated by the interlock of the upper and lower teeth. Overshot  can affect the mouth’s function more than undershot and indicates usually weakness in the lower jaw.

The incidence of level bites is increasing among Catahoulas beside some missing teeth. Undershot bite is one of more serious faults that occur in this breed. There is no doubt that such faults and abnormalities are inherited. Upper and lower jaws grow independently, factors influencing a size of jaw are different from those affecting the size of teeth and various genes are involved in this process. These problems are polygenic resulting from the action of many genes, thus it is difficult to eliminate them because there is no single „bad bite“ gene.  The length of the skull and the muzzle play a role and a dominant way of a shorter skull inheritance is known. Thus, this must be taken into account in case of Catahoula, too. A combination of parents with rather different length of their muzzles is not recommended, because it could increase the incidence of faults in bites and occurrence of undershot or overshot bites among offsprings. And we have proved already that Catahoulas may vary in their muzzle size in more than one third of its length.

Inheritance and elimination of severe dental faults is difficult in breeds more numerous than Catahoula. There is impossible to exclude from breeding all individuals that show any fault due to complicated, polygenic and often recessive way of inheritance in such a rare breed. However, those showing more serious faults, such as the overshot and the undershot bite and numerous and the most important teeth missing, should be surely excluded from breeding.

There was no much attention paid until now to bite and teeth quality of Louisiana Catahoula. The reason is that Catahoula is the American breed and there is generally only a little attention focused on this matter. Both NALC standard, valid since 1977 (last revision in 1994) and UKC standard (2008) say that: „A scissors bite is preferred, but a level bite is acceptable. Full dentition is greatly desired, but dogs are not to be penalized for worn or broken teeth. Overshot or undershot bite are serious faults, but not disqualifying“. Catahoula is working breed and working qualities have been always more demanded than an ideal conformation and a superior bite. This is also the heritage we must deal with now.

Evaluation of European breeds and breeding was always more strict in this point of view and more focused on correct bite and full dentition, namely in breeds that preserve more or less normal skull parameters. Thus, scissor bite and full dentition is what most of breed standards demand and faults are more penalized. There is a good reason for it, because an efficient function needs a proper skull and jaw structure and teeth position. However, some anomalies were found also in wild living wolves and some faults are fairly common among various dog breeds even if not wanted.

Full dentition with all adult teeth fully erupted consist of incisors (Incisives – I), canines (Caninus – C), premolars (Praemolares – P), and molares (Molares – M). Upper and lower jaw differ in a number of molars. The teeth pattern is following:

In training and performing Schutzhund the preferred grip is a „full mouth bite“. The dog should grasp subject’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 and their overlapping structure combined with jaw strength prevents the prey from pulling free. Once the prey is down, the premolars are used for biting off chunk of meat. The upper P4 and the lower M1 on each side are especially developed for this task. The carnasals 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. The incisors located at the front of the mouth are specialized for delicate work. They nibble the last bits of meat off bones and are also handy for scratching an itch or pulling something bothersome out of the coat or from between the pads. Molars, other than mentioned, are flat for grinding plant matter. Wolves eat also some fruits, grasses and other plant matter and this type of food must be chewed a little to start digestive process.

All those specialized teeth have their proper position in the jaw, which 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. Jaw strength comes not only from the muscles, but the shape of the skull (1).

Research among wild wolves showed that the most frequent anomaly was the absence of the last molar in the lower jaw, M3. As it does not change the function, the absence of M3 should not be considered breeding deficiency also in dogs (2).

Faults of bite concern also Catahoula breed. Dog’s bite is the way his teeth fit when his upper and lower jaws are closed. The standard type is a scissor bite, in which the upper incisors just overlap and touch the lower incisors and all premolars and molars fully fit. Another possible variation is a tight scissor bite, when upper and lower incisors touch each other more then above or lower incisors are outwards of longitudinal line of bottom jaw. Catahoula has also a level (even) bite permitted by the breed standard. It is when the upper and lower incisors meet exactly, surface to surface. This means that teeth can be worn down much faster, but it does not affect actually the function and both jaws are of the same length as in previous cases. Level bite is considered normal in some breeds, including Catahoula, nevertheless,  some consider this type of bite as an expression of underbite. On the other hand, research among wild wolves showed that fully a third of animals 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.

Undershot bite is when the upper jaw is perceptibly shorter than the lower jaw and the lower incisors are located in front of the upper ones. This is typical for some breeds such as Boxer, Bulldog, Pug, Pekinese, etc. that have a shorter foreface and longer lower jaw.

Overshot bite is caused by physically longer upper jaw than the lower one and the uneveness between them is larger than 2 mm. This fault occurs more often among dog breeds nowadays. Contrary to undershot, this fault can be controlled by genetics, nutrition, environment and by mechanical forces generated by the interlock of the upper and lower teeth. Overshot  can affect the mouth’s function more than undershot and indicates usually weakness in the lower jaw.

The incidence of level bites is increasing among Catahoulas beside some missing teeth. Undershot bite is one of more serious faults that occur in this breed. There is no doubt that such faults and abnormalities are inherited. Upper and lower jaws grow independently, factors influencing a size of jaw are different from those affecting the size of teeth and various genes are involved in this process. These problems are polygenic resulting from the action of many genes, thus it is difficult to eliminate them because there is no single „bad bite“ gene.  The length of the skull and the muzzle play a role and a dominant way of a shorter skull inheritance is known. Thus, this must be taken into account in case of Catahoula, too. A combination of parents with rather different length of their muzzles is not recommended, because it could increase the incidence of faults in bites and occurrence of undershot or overshot bites among offsprings. And we have proved already that Catahoulas may vary in their muzzle size in more than one third of its length.

Inheritance and elimination of severe dental faults is difficult in breeds more numerous than Catahoula. There is impossible to exclude from breeding all individuals that show any fault due to complicated, polygenic and often recessive way of inheritance in such a rare breed. However, those showing more serious faults, such as the overshot and the undershot bite and numerous and the most important teeth missing, should be surely excluded from breeding.

Occlusion refers to the relationship between the maxillary and mandibular teeth when they approach each other, as occurs during chewing or rest. Normal occlusion exists when the maxillary incisors just overlap the mandibular incisors (Figure 1A), the mandibular canines are equidistant from the maxillary third incisors and the maxillary canine teeth, and the premolar crown tips of the lower jaw point between the spaces of the upper jaw teeth in a saw-toothed fashion (Figure 1B). Flat-faced breeds, such as boxers, shih tzus, Boston terriers, Lhasa apsos and Persian cats, have abnormal bites that are recognized as normal for their breed in which the mandibular jaw protrudes in front of the maxillary jaw, altering the above tooth-to-tooth relationship (Figures 2A and 2B).

Malocclusion refers to abnormal tooth alignment. Skeletal malocclusion occurs when jaw anomalies result in abnormal jaw alignment that causes the teeth to be out of normal orientation. Dental malposition occurs when jaw alignment is normal but one or more teeth are out of normal orientation.

Mandibular distoclusion (also called overbite, overjet, overshot, class 2, and mandibular brachygnathism) occurs when the lower jaw is shorter that the upper and there"s a space between the upper and lower incisors when the mouth is closed. The upper premolars will be displaced rostrally (toward the nose) compared with the lower premolars. Mandibular distoclusion is never normal in any breed (Figures 3A and 3B).

Figure 4. Mandibular mesioclusion in a dog.Maxillary mandibular asymmetry (also called wry bite, especially by breeders) is a skeletal malocclusion in which one side of the jaw grows differently from the other side (Figures 5A and 5B).

In humans, identifying a clear underbite is quite simple, as we all have relatively similar jaw structures. There is a clear definition and appearance for what is “normal” when it comes to dental health. However, when it comes to canines, there is a less clear definition of “normal.”

In some breeds, underbites are actually the result of intentional breeding practices. Some breeders may breed their pups specifically to engineer the type of jaw structure of a bulldog or a boxer. Like other questionable breeding practices, this crosses a line for some people. Underbites can cause discomfort and health problems for some dogs, so many believe that intentionally breeding underbite dog breeds is wrong.

This misalignment can sometimes self-correct as the dog develops. This is particularly true in some breeds with more pronounced muzzles, in which slight underbites are common. With that said, most small dogs that show symptoms as a young puppy will likely have a dog underbite for the rest of their lives. As a rule of thumb, the alignment of a dog’s teeth is typically permanent once it reaches about 10 months old—although this can vary from breed to breed.