Jaw and Order: Find out what causes imperfect bites and how you can help improve your dog’s smile.
D. Caroline Coile, Ph.D.
“May I see the bite?” Those five words can signal the difference between winning or losing in the show ring. But correct dentition means more than a ribbon, and it entails more than seeing how the incisors meet up. It involves the relationship between all the teeth, the orientation of individual teeth and whether the dog has the correct number of teeth. In dogs with long or medium-length muzzles, the ideal occlusion consists of several components:
1. The upper incisors should be just in front of the lower incisors, so the tips of the lower teeth touch the inner surface of the upper teeth about one-third of the way up. This is called a scissors bite.
2. The lower canine teeth (fangs) are inclined slightly out to the sides, and fit in a space outside of the upper gum just in front of the upper canine tooth.
3. The upper premolars (the teeth behind the canines) should lie to the outside of the lower premolars. The premolars never meet tip to tip; the tips instead fit in the spaces between the opposite jaw’s premolars.
4. The upper fourth premolar, or carnassial tooth (the really big one in the rear upper jaw), should lie directly outside the lower fourth premolar and first molar teeth.
How do the teeth of the two jaws end up in the correct position relative to one another? To some degree, the dental interlock created by the teeth causes the jaws to grow at roughly the same rate. As the upper jaw grows, it pulls the lower jaw along with it because the lower fang is being pushed by the upper fang behind it. It’s not uncommon for developing puppies to have a slight overbite at some stages, but if the lower canine is positioned behind the upper canine, then the lower jaw will be blocked from catching up to the upper jaw. Extraction of the lower or upper deciduous (baby) canines can prevent this barrier, but unfortunately, removes the dental interlock that also encourages the growth of the lower jaw, and the bite may remain overshot.
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