FORM FOLLOWS FUNCTION
In the upper jaw, there are six incisors, two canines, eight pre-molars, and four molars. The lower jaw has six incisors, two canines, eight premolars, and six molars for a total count of 42 (20 upper, 22 lower) teeth. (See Figure 2.) More on how to count teeth later. What role does dentition serve in the function of the dog? The 12 incisors (six upper and six lower) consist of two central incisors, two intermediate incisors, and two lateral incisors. (See Figure 3.) Incisors share a single, com- mon root. The incisors are used to rip and scrape food from bones as well as to remove detritus/insects/irritants from the coat, and to help pick up and carry objects. The incisors are also used as a landmark in determining the bite of the dog. To simplify: When incisors meet tooth- to-tooth, this is a level bite. (See Figure 4.) When the upper incisors overlap the lower, but are touching or in very close proximity to the lower incisors, this is considered a scissors bite. (See Figure 5.) An overshot dog is one in which the upper incisors have a noticeable forward gap ahead of the lower incisors, and if a scissors bite is called for, the severity of the fault is deter- mined by the size of the gap. (See Figure 6.)
Figure 6. Overshot Bite
Figure 7. Undershot Bite
UPPER AND LOWER CANINES
Figure 8. Canines from the Front
Figure 9. Premolars P1, P2, P3, P4; Molars M1, M2 Upper and M1, M2, M3 Lower
When the bottom incisors are in front of the upper incisors, but either touching or in very close proximity to the lower incisors, this is consid- ered a reverse scissors; but is considered undershot when there is a slight (or more) gap. Again, a noticeable forward gap of the lower incisors from the upper incisors is considered a fault if a scissors bite is called for in the standard of the breed. The severity of the fault is determined by the size of the gap. (See Figure 7.) The canine teeth are often referred to as fangs, and they reside right next to the incisors in the upper and lower jaws of the dog. When the dog’s mouth is closed, to form the scissors bite, the canine teeth should intersect and not conflict with the teeth of the opposite jaw. Canines are sharp and come to a point, and they are single-rooted teeth. The canine teeth serve the dog as a defense mechanism—those pointed teeth can cause severe puncture wounds to ward off other dogs or larger predatory animals. They also help the dog bite and hold on to a toy or bone as well as serve the dog well to bring down game. The canines help in holding prey once caught and they are an aid in tearing the prey apart for consumption. The Herd- ing breeds use the teeth to nip at the heels of their livestock and to threaten them from the front when turning and heading stock. Each pair of canines is separated by a set of incisors. (See Figure 8.) The premolar teeth are located in the jaw behind the dog’s canine teeth. They are irregular and closely spaced. As they approach the molars, they become larger and more complex. The first premolar has one root, the second and third have two roots, and the fourth (Carnassial tooth) has three roots. The premolars are necessary for chewing, and the Carnassial tooth is adapted for shearing flesh. A dog will take a treat from you with his canines and incisors and then move it over to the side of his mouth to chew the meat off the bone. There are 16 premolars; four on either side of the upper and lower jaws, just behind the canine teeth. (See Figure 9.)
Figure 2. Adult Teeth; 1-3 Incisors, P 1-4 Premolars, M 1-3 Molars
Figure 3. Incisors are within the dotted box.
Figure 5. Scissors Bite
Figure 4. Level Bite
76 | SHOWSIGHT MAGAZINE, JULY 2021
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