Continued from last week

Over the past few weeks, I have been making references to the malformation of the jaws which result in an incongruence of the teeth in the upper and lower jaws, simply put: an incorrect bite.

I have found a text that deals with the problem at a very basic and understandable level. Since I cannot improve on the way the subject matter was handled, I will largely reproduce the text from Drs Carlson and Grifffin.

20131103steveIncorrect bite: A bad bite is a common problem and causes dog breeders more concern than any other mouth abnormality. The ideal bite for most breeds is a scissors bite in which the upper incisors just overlap and touch the lower incisors. In an even or level bite, the incisors meet edge to edge. This is a common bite in dogs but is not considered ideal because the edge to edge contact causes wear to the teeth (and the mouth does not close correctly as well).

The type of bite a purebred dog should have is given in the Standard for that breed.

Overshot: In this condition the upper jaw is longer than the lower jaw, so that the teeth overlap without touching. This case is also called a parrot mouth. This problem, which occurs in young puppies, may correct itself if the gap is no greater than the head of a matchstick. Most bites are ‘set’ by the time a puppy is 10 months old. An overshot bite seldom improves thereafter.

A puppy with an overshot mouth could have a problem when his permanent teeth come in, as they may injure the soft parts of the mouth. These bites should be watched carefully as teeth extractions may be necessary.

Undershot: This is the reverse of what was just described, with the lower jaw projecting beyond the upper. It is considered correct in some of the short-faced breeds, including the Bulldog, Boston Terrier and Boxer.

Wry mouth: This is the worst of the malocclusion problems. In this situation, one side of the jaw grows faster than the other side, twisting the mouth so as to give it a wry look. This condition can be quite a handicap and leads to difficulty grasping, chewing and gnawing food material.

NB In all my 47 years as a small animal practitioner, I have never encountered such a case. So it must be a rare occurrence. Perhaps in North America this condition presents itself more often, and that is why the textbooks tend to list this defect under the heading of “problems of the jaws and the face bones”.

Treatment of incorrect bite: most bite problems are due to hereditary influences which control the length of the jaws, so that one grows at a different rate than the other. An overshot mouth in which the upper jaw grows faster is definitely hereditary and may be passed on to some members of the next generation. The undershot mouth seems also to be hereditary. Dogs with hereditary dental malocclusion problems should be eliminated from breeding programmes.

Bad bites in dogs can be due to retained baby teeth which interlock in such a way as to block the normal growth of the jaws. When abnormal tooth development is detected early (by two weeks), often the problem can be corrected by extraction of the offending milk teeth.

In the end, really, puppies with obvious inherited defects should not be allowed to survive unless they are spayed/castrated, so that they cannot reproduce and carry on the defective genetic strain (line). As always euthanasia must be discussed at length and in depth with your veterinarian.

Please implement disease preventative measures (vaccinations, routine dewormings, monthly anti-heartworm medication, etc) and adopt-a-pet from the GSPCA’s Animal Clinic and Shelter at Robb Street and Orange Walk, if you have the wherewithal to care well for the animals. Do not stray your unwanted pets, take them to the GSPCA’s Clinic and Shelter instead. If you do not wish your pet to have puppies or kittens, you may exploit the GSPCA’s free spay and neutering programme. If you see anyone being cruel to an animal, or if you need any technical information, please get in touch with the Clinic and Shelter by calling 226-4237.