|SECTION I||GENERAL DESCRIPTION OF CANINES|
OBJECTIVES FOR SECTIONS I AND II
These sections are designed to prepare the learner to perform the following:
- Describe the location of canines in the mouth.
- Describe the functions of canines.
- List the class traits that apply to all canines. Include the incisor class traits that also apply to the canines.
- From a selection of all permanent teeth (or from drawings or photographs of all teeth from various views), select and separate out the canines.
Ideally, use a cast of all permanent teeth and Figure 3-1 while studying about the position of the canines within the arch. There are four canines: one on either side in the maxillary arch (Universal numbers 6 and 11) and one on either side of the mandibular arch (numbers 22 and 27). They are the longest of the permanent teeth.A The canines are distal to the lateral incisors and are the third teeth from the midline. The mesial surface of the canine is in contact with the distal surface of the lateral incisor. The distal surface of each canine contacts the mesial surface of the first premolar. The four canines are numbered in the mouth in Figure 3-2.
The four canines are justifiably considered cornerstones of the arches, as they are located at the corners of the mouth or dental arches. They are often referred to as cuspids (having one cusp), but also as eyeteeth or fangs, both slang nicknames that should be discouraged. Frequently, the canines are often the last teeth to be lost from decay and periodontal disease. Have you known or seen an elderly person who is edentulous (toothless), except for one or more of the canines?
In dogs, cats, and other animals with long, prominent canine teeth, the functions of these teeth are for catching and tearing food and for defense. As a matter of fact, caninus in Latin means “dog.” Canines are essential to their survival. In human beings, these teeth usually function with the incisors (a) to support the lips and the facial muscles and (b) to cut, pierce, or shear food morsels. A steep overlap of the maxillary and mandibular canines, when present, serves as (c) a protective mechanism since, when the mandible moves to the side during function, the overlapping canines cause the posterior teeth to separate. This is called canine guidance, and it relieves the premolars and molars from potentially damaging horizontal forces while chewing.
Touch your back teeth into the position where they best fit tightly together. Then move your lower jaw to the right. Not all people have canine guidance, but if you do, your back teeth should separate as you move the lower jaw to the right or left side. Do they? If they do, can you tell if it is the overlap of the canines that cause them to come apart? As you begin to move your lower jaw to the side, are the canines the only teeth that touch?