| SECTION IV | INTERESTING FACTS AND VARIATIONS IN CANINE TEETH |
The name canine is of Greek origin and is found in the writings of Hippocrates and Aristotle of 2350 years ago. Aristotle first described canine anatomy, stressing the intermediate nature of it between incisors and molars. About 2000 years ago, Celsus was the first writer to mention the roots of teeth, saying the canine was monoradicular (i.e., normally having one root).3,4
A conspicuous but rare variation in canine teeth is found in a mandibular canine tooth with the root divided into labial and lingual roots. These roots may be split only in the apical third, or the split may extend into the cervical third of the root (Fig. 3-17).
FIGURE 3-17. Two unusual mandibular canines, each with a split (bifurcated) root that has a facial and lingual root tip.
Although the maxillary and mandibular canines are most often the longest teeth in their respective arches, observe the enormous variation in size and shape among several maxillary and mandibular canines in Figure 3-18.P
FIGURE 3-18. Canines of differing size reveal tremendous variation in the length of canines.
A maxillary canine with an unusual notch on its mesial cusp slope is seen in Figure 3-19. An unusual canine with a shovel-shaped lingual surface is evident on tooth 11 in Figure 3-20. Other anomalies will be described in Chapter 11.
FIGURE 3-19. Maxillary right canine with an unusual deep notch in the mesial cusp ridge.
FIGURE 3-20. Maxillary left canine (arrow) with unusual shovel-shaped lingual anatomy (very prominent marginal ridges).
Perhaps the most unique canines of all occur on the male Babirusa (type of wild boar) seen in Figure 3-21. Its two enormous maxillary canines curve backward, piercing the bony snout on each side. Then, they curve in a large arc upward, backward, and finally down toward the forehead. These unusual maxillary canines serve only to protect the boar’s eyes and upper face. The Babirusa’s mandibular canines are also very large and tusk-like, and curve up and back, possibly serving to protect the side of the face and for fighting or piercing food when the jaw is opened wide.
FIGURE 3-21. A male Babirusa (type of wild boar) with extremely unique canines that actually pierce the upper lip and bony snout on each side.
REVIEW Questions
For each trait described below, indicate the letter of the best response from the five selections provided. Each trait has only one best answer.
- Maxillary central incisor
- Maxillary canine
- Mandibular canine
- All of the above
- None of the above
|
a b c d e a b c d e a b c d e a b c d e a b c d e a b c d e a b c d e a b c d e a b c d e a b c d e |
ANSWERS: 1–d; 2–b; 3–c; 4–d; 5–c; 6–a; 7–b; 8–a; 9–d; 10–d; 11–e
CRITICAL Thinking
1. The only way to master the many traits of the canine presented in this chapter is to be able to picture each trait in your mind for maxillary and mandibular canines, and for each side of the mouth. Therefore, even though you have probably already looked carefully at each illustration in this chapter, at this time reread the legends and study each figure in this chapter. If any facts are unclear, review the portion of the chapter that referred to that figure. Also, use the front and back of appendix pages 3 and 4 to review all identified traits of canines.
2. While viewing a model or a picture of the facial surface of a mandibular left canine, list as many traits as possible that you can use to differentiate the right side of the tooth from the left side within two columns labeled right side and left side. For example, under left side of the tooth as you view the mouth from the facial, you could write that the left (mesial) cusp ridge is almost horizontal. Then repeat all of the traits using the terms mesial and distal.
3. Repeat exercise #2 when viewing the lingual view of the maxillary right canine.
4. Search on a computer for images of “people with tribal tooth sharpening,” and select five images to answer the following questions:
• What are the Universal tooth numbers of the teeth you think have been reshaped? Do you think that the reshaping has added to the beauty of the person?
5. Search on a computer for images of “people with fangs,” and select five images in order to answer the following questions.
• What teeth are exaggerated in sharpness? Can you tell if the pointy teeth are real or fake? Perhaps the term “fang” is not a good word to use when speaking of canines.
6. Search on a computer for images of “people with missing lateral incisors,” and select five images in order to answer the following questions.
• Are the spaces where the lateral incisors would normally be located still present? These spaces could have been “filled in” by using braces to reposition the canines into the spaces, or by replacing the lost teeth with artificial teeth (like a bridge or an implant). If there are no spaces, does the tooth in place of the lateral incisor look more like a lateral incisor or a canine? Also, be aware that canines can be made to look somewhat like lateral incisors by reshaping some of the hard outer enamel, or a canine could have a crown that is shaped more like a lateral incisor. Can you tell if the teeth in place of the missing laterals have been reshaped or crowned?
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