Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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Dental FAQs


How common are bad bites in Aussies?

According to the 2009-10 ASHGI health survey, 10% of breeding dogs produce bad bites.

What is an undershot bite?

The lower jaw protrudes beyond the upper, causing the lower incisors to lie in front of the upper when viewed from the side.

What is an overshot bite?

The upper jaw isn’t long enough, resulting in the lower incisors to lie 1/8th inch or more behind the upper incisors.  Lower canines will sometimes be positioned behind the upper canines.

What is parrot mouth?

A very severe overshot bite.

What is anterior cross-bite? 

The lines formed by incisors in the upper and lower jaws will cross each other, resulting in some lower incisors protruding in front of the upper.

What is  a wry bite 

The sides of the lower jaw grow unevenly, leaving the jawbone to some degree lopsided.  Teeth will be misaligned where the jaw is malformed.

What is a level bite?

The upper and lower incisors meet at the tips.  This is a minor fault under the ASCA standard and not faulted under the AKC and FCI standards.  Level bites are functional.  A survey of wolf dentition in the 1980s found that about 10% have level bites further indicating that there is no loss of function.

Will bad bites correct?

The jaws should grow about equally, so that the teeth stay in alignment.  Sometimes there will be a little uneven growth that temporarily results in a bad bite that later corrects.  Slightly undershot jaws seem less likely to correct than slightly overshot.  Gross differences are not going to correct completely.  Usually the jaw structure will be set by about 6 months, so if a bite is off at that point it will probably remain so (though there are rare exceptions.)

Is it OK to breed dogs with bad bites?


Is there anything other than heredity that can cause or correct a bad bite? 

Physical trauma to the jaw might result in a bad bite, but the type of trauma that would cause that isn’t likely to go unnoticed.  If the bite isn’t very far off, braces or other dentistry techniques might correct it but minor bad bites rarely cause the dog enough trouble to justify the expense.  In show animals such alterations are in violation of show rules.  In breeding animals they are perpetrating a fraud.

How are bad bites inherited?

The specific genetics of the various forms of bad bites are yet to be determined.  Given the complex structure of the teeth and jaws, inheritance is likely complex.  The frequency of bad bites can be minimized by not breeding dogs that have produced them to mates that have either produced them or have a family history of bad bites.  Breeding for a length of jaw that equals the length of the topskull and for a slightly tapered muzzle will also minimize the number of bad bites; short, blocky muzzles tend to increases frequency.

What should I do if I produce puppies with bad bites?

Minor bad bites don’t cause the dog any significant difficulty; these pups can be placed in non-breeding homes.  Severe bad bites may cause difficulty eating.  Depending on how the teeth are aligned it may be necessary to remove the lower canines to prevent damage to soft tissue on the upper jaw.  Pups with severe bad bites might be placed in non-breeding homes provided the new owner is aware of the problems the dog may experience due to the bad bite.

Are extra teeth common in Aussies?

No.   The extras are usually premolars or molars, though there has been a report of one dog that had eight incisors in one jaw.

Are they a problem for the dog?

Extra teeth may interfere with dental function depending on where the teeth are placed and how large they are.  Large or badly placed extra teeth might actually be more of a problem for proper jaw junction than missing teeth, particularly the first premolars.

Does having an extra tooth make up for missing one somewhere else in the mouth?

No.  Dogs should have a particular number and configuration of teeth.  Any deviation from that should be considered faulty.  How faulty it is depends on the degree of deviation.  One tooth missing or extra is less a problem than five.  However, having an extra one does not make up for any that might be missing; such a dog is more faulty than if it only had one or the other.

 Are extra teeth hereditary?

Unknown, but it is best to assume that they are and consider them faulty.  The degree of fault of faultiness would depend on how many teeth extra teeth there were and whether they in any way interfere with the normal functioning of the jaws.  If there are only one or two and jaw function isn’t impaired, there is no reason to eliminate an otherwise good quality dog from breeding.   However, it should be bred to mates with normal dentition from families where extra teeth are not known.

What teeth are likely to be missing in Aussies?

Premolars, the first four teeth behind each of the canines, are the ones most likely to be absent.  A dog is supposed to have sixteen of them.  Occasionally a dog will be missing a molar and, very rarely, incisors (the front teeth.)

How do I know missing teeth in a young dog won’t come in later?

Teeth that haven’t erupted within a few weeks of the time they should have are almost certainly absent.

 How does this happen?

It is a developmental defect – the teeth fail to develop at all or are incompletely developed and fail to erupt.

If the dog is x-rayed and they found a tooth bud in the jaw, is it really a missing tooth?

Yes.  X-ray may reveal a tooth bud, but it still isn’t there when you open the mouth and look.

 Does having an extra tooth somewhere else make up for one that’s missing?

No.  Aussies will occasionally have an extra tooth or two.  These are usually premolars though on rare occasions they may be molars or incisors.  The normal canine jaws have a particular configuration of teeth with certain types in certain positions.  Any deviation from that interfered with proper jaw function.  Missing a tooth in one position and  having an extra one somewhere else doesn’t balance things out, it mean the dog has two dental defects instead of one.

 What does having missing teeth mean for my dog?

Missing teeth have little or no impact on the dog’s health but jaw function may be affected depending on which teeth and how many are missing.  Aussies are supposed to have a full complement of teeth, so if any are missing the dog is faulty.  Missing teeth are faulted but the degree of fault varies depending on the number missing.  Multiple missing teeth, particularly if they are neighboring teeth, can interfere with function:  While not defined by the breed standards, which teeth are missing affects function.  The P1 teeth (first premolars) are small and their absence doesn’t make a great deal of difference providing the P2s are still there.  However, if an upper P4 or the lower first molar (the large shearing teeth) were missing, that is a far serious fault from a functional standpoint.  Other missing molars would also be more serious than missing premolars, with the exception of the upper P4s.

Having multiple missing teeth is very faulty in a breed that should be physically capable of performing its original function.  If a dog is involved in work or performance events, missing teeth may have an impact depending on which teeth and how many are missing.  A dog with multiple missing teeth may have trouble holding a grip on a dumbbell or other item.  Multiple adjacent missing teeth may weaken the jaw structure; with greater risk of injury should the dog be struck on that part of the jaw by something like a flying hoof.  In conformation the dog should be faulted, but how much will depend not only on the number of teeth but on the judge and the quality of the other competitors.

How common are missing teeth in Aussies?

Very common.  9% of the dogs in the 2009-10 ASHGI health survey were missing at least one tooth.  Two fifths of them were missing multiple teeth.  P1s and P2s were the most likely to be missing.

Are missing teeth inherited?

Yes.  The specific genetics of missing teeth are unknown but due to the complex structure of the canine jaw and teeth it is likely that multiple genes and possibly gene regulation factors are involved.  A dog that is missing teeth is very likely to produce offspring that are missing teeth.

What do missing teeth mean for my breeding program?

The best approach for a breeder to the problem of missing teeth is to determine the dental status not only of your own dogs and their potential mates, but of as many ancestors and other relatives as possible.  Breadth of pedigree, including the status of collateral relatives, is more important than simply knowing the status of progenitors.  Since missing teeth are highly variable as to numbers and which specific teeth are missing, the degree to which the dog is affected needs to be considered.  The less faulty might be bred but the more faulty should not.

Dogs that are missing teeth, their parents, offspring, and full and half siblings should be bred only to mates with full dentition from families where missing teeth are rare or do not occur.  Do not repeat breedings that produced missing teeth and do not use males with missing teeth extensively at stud.

What is a cleft palate?

Sometimes the bones and other tissue inside the upper jaw fail to close properly, leaving an opening between the mouth and the nasal passages.  The size of the cleft can vary from, an opening in the roof of the mouth to a gap that divides the gum and underlying bone in the upper jaw and even up to the nostrils.

 How do I know if a puppy has a cleft palate? 

The most severe forms will be readily visible.  Those which are confined to the inside of the mouth may not be so obvious but all cleft palates interfere with nursing because the puppy can’t get suction due to the cleft and may even get aspiration pneumonia by breathing milk into the lungs.  If a newborn puppy isn’t nursing properly or doesn’t seem to be doing well, take a peek at the roof of the mouth.

 What can be done for a puppy with cleft palate?

Caring for a puppy with cleft palate can be difficult.  They must be tube fed to make sure they get enough food and don’t aspirate any.  A tiny cleft may close on its own, but most will require surgery to fix.  Sometimes the kindest thing to do is euthanize the puppy to spare it a prolonged and unpleasant death.

 How common is cleft palate in Aussies?

It is rare.

 Is cleft palate inherited?

It can be, but there is no evidence that is the case in Aussies.  Cleft palates may be due to accidents of development or caused by toxic exposure prior to birth.  In the 1980s and 1990s there was an x-linked syndrome of multiple skeletal defects that included cleft palate, but this was only in one isolated family of dogs and is unlikely to be present in the breed any longer.

 What does cleft palate mean for my breeding program?

It probably is not a breeding concern, unless you are seeing it happening in related litters raised in different environments.