Australian Shepherd Health & Genetics Institute

Australian Shepherd Health & Genetics Institute

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Missing & Extra Teeth


Are extra teeth common in Aussies?

No.  The extras are usually premolars or molars.

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 because they may interfere with function.

What teeth are likely to be missing in Aussies?

Premolars, the first four teeth behind each of the canines; dogs are 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.  An unerupted tooth is as useless as an one that is absent.

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.

Are extra teeth hereditary?

Unknown, but it is best to assume that they are and consider them a fault.  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 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.  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 very 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 its 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 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 and their near relatives 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.