The Dog's Medical Dictionary / An encyclopædia of the diseases, their diagnosis & treatment, and the physical development of the dog

by Alfred Joseph Sewell

The milk teeth are seldom placed close together, and as the puppy grows, they become still wider apart. This fact is useful in helping one to ascertain the age of a puppy.

The deciduous teeth are much softer than the permanent ones, and when a pup is three months old, if it has had any hard food, the points of the tusks and incisors are worn off.

When a puppy is about three and a half to four months old, the upper incisor nippers are loose, and sometimes have fallen out, and the permanent ones are just coming through the gums at this part. At the same time, the fourth upper molar, which is the fourth from the tusk, makes its appearance. (It will be noticed that though the lower temporary molars are cut before the upper ones, the reverse is the case with the permanent teeth.) In the course of another few days, or a week, the other upper deciduous incisors are shed, and the permanent ones appearing in their place, then the lower milk incisors commence to fall out, and the new ones to make their appearance. About the same time the tusks are showing themselves through the gums. In some cases, the tusks do not appear until all the other teeth are up. This is about the general order in which the teeth are cut, but of course there are exceptions, and in some instances, the permanent tusks appear just after the eruption of the upper centre incisors.

It does not always happen that the temporary teeth are shed before the permanent ones appear, and the latter shoot up either beside, in front, or behind the milk teeth. Then the latter teeth should always be drawn, or the permanent ones may not come straight and regular.

With regard to the permanent molars, the first to appear, as previously stated, is the fourth one. It makes its appearance just behind the last temporary molar. Before it is fully up, the fifth upper molar has passed through the gum. At about this same time the fifth, or large permanent lower molar, is appearing; this is quickly followed by the sixth, and again by the seventh. About the same time as these two latter teeth are erupting, the temporary molars in the same jaw are falling out, and their places are being filled by permanent ones. About a week later, the first lower milk molar is shed and the permanent one cut; this is followed by the second and third ones. The corresponding teeth on each side of the jaw, as, for instance, the fourth molar on the left and right sides, are erupted simultaneously. By the time puppies, such as St. Bernards, mastiffs, retrievers, and others of similar size, are about four months old, the process of dentition is complete. Fox-terriers, and other dogs of this size, are in some cases a fortnight later, and small toy dogs are often from six to eight months of age, or even later, before the mouth is fully furnished.

It is impossible to tell the age of a dog with any certainty after dentition is finished, but up to then one can judge the age to within a fortnight, if it is borne in mind how the teeth are erupted. After this time, and up to a year or eighteen months, if, together with the condition of the incisor teeth, whose middle prominences at this time show signs of wear, one takes into consideration the general appearances of a dog, a fair judgment as to age may be formed.

Later, the wear of the teeth gives no good idea of the age, because so much depends upon the kind of food the animal eats, whether it is hard or soft. When a dog is fed on bread and gravy or meat, the teeth will show little or no signs of wear when he is two or three years old, while the incisor teeth of another dog of the same age will commence to become blunted if biscuits form the staple food. The teeth become still more worn if a large number of bones are given as a part of the diet. And again, dogs who are always playing with and carrying stones often wear the incisor teeth right down to the gums, and the tusks become worn in the course of a few years.

As a rule, if a dog is fed on a mixed diet, as bread and vegetables, soaked biscuits, etc., and not given many bones, and is not allowed to carry stones, then the teeth (incisors and tusks) preserve their shape and position until the fourth year. But by this time the teeth have lost their very white colour, and have become of a palish yellow colour. As the dog advances in years the teeth become still more yellow, besides becoming coated with tartar just above the neck of the tooth, if they have not been occasionally scaled. The tusks, too, now become blunted, and to some degree are altered in position, being inclined to take a more outward direction. It is, therefore, an easy matter to distinguish between an old and a young dog.

The teeth of dogs that are pig-jawed, and those that are undershot like bulldogs, do not, of course, wear to the same extent as when the incisors meet, forming an even mouth.

When the permanent teeth come up crooked, it is a most difficult thing to redirect them, especially when the tusks are at fault, and they are generally the offenders; for these teeth are so firmly and deeply fixed in the jaw-bone that it is impossible, without employing great force, to move them, and from their conical shape it is almost impossible to fix a rubber band or wire to them unless a small niche is made in the enamel, and this damages the teeth and renders them liable to decay. When the tusks grow inwards so as to injure the palate, I have, after a great deal of trouble, fixed a wedge made of hard wood between the two tusks of the lower jaw, but it always comes out within a few hours. Again, when the incisors, or front teeth, come up twisted or crooked, and one tries to turn them with forceps, the operation is seldom successful; the tooth is almost sure to break, as dogs’ teeth are so brittle. More good is to be done by pressing the erring teeth in the right direction with the fingers; and when they are not very badly misplaced, a good deal of benefit may be derived by this simple treatment. It should be done two or three times a day for ten minutes at a time. Pressure of this kind is very useful to the upper or lower incisor teeth in slight cases of undershot—that is, when the lower incisor teeth project in front of the upper ones; or when the upper incisor teeth project in front of the lower ones—called “pig-jaw.” Either of these conditions is a great drawback to a terrier; and some judges, who are particular, and examine the mouth, will often put a dog back for this defect. In bad cases I think he is right to do so; but it is rather hard on the dog when there is only a slight unevenness, because I think he can hold just as well as one with an even mouth.