Section 4-1. Teeth hold the micro cosmos. Its kinds and structure.

The vivid elderly person study made me recognize that teeth are organs. I was wondering previously whether dental prophylaxis is worthy or not, and whether significance of our own teeth possesses something precious which cannot be substituted by artificial teeth or not. My long-lasting questions as a dentist and a researcher revealed the lethal blind points clearly which could not be noted despite existing just in front of myself. Solution of one question invites another unexpected question, which discloses another question like a chain reaction. The succession of question and answer resembles excavation of mineral vein. While struggling with studies requiring lots of time and efforts, and coming into conflict with weariness of pending questions which cannot be solved by conventional dental medicine, we proceeded step by step; however, such efforts are the real pleasure for researchers. I feel very happy if you recognize the correlation between teeth and the systemic functions of our body.
For human beings, teeth can be regarded as a precious gem which hides miraculous potentials. I believe that teeth can be designated as diamond holding a key for maintaining health of the human beings. It is of real regret that this fact had been veiled for a long period of time. 　However, now that the twenty-first century has been dawned, such a mysterious veil is uncovered and this trend is really significant. In the near future, human being would be exposed to a globally scaled environmental change. Nevertheless, it can be anticipated that human beings could survive under such a situation. The last master card provided by the God is “Teeth”.
As one drop of sea water tells us the sea, one tooth hides a mystery of the microcosmos, our body. For your better understanding of the theme of this book, I wish to explain the structure of teeth, a living gem, as its fundamental information. I am confident that you could understand that teeth are not the mere inorganic lump but a living gem which possesses mysterious potential from the view point of both structural and functional features.
As you might know, baby teeth are defined as the teeth during childhood while adult teeth are the teeth which replace baby teeth until puberty. Baby teeth comprise desiduous medial incisor, desiduous lateral incisor, deciduous canine, deciduous first molar teeth and deciduous second molar teeth, bilaterally amounting to 20 teeth in total. Adult teeth consist of the following 8 kinds of teeth such as medial incisor, lateral incisor, canine, first cuspid, second cuspid, first molar teeth, second molar teeth and third molar teeth (wisdom teeth), bilaterally amounting to 32 teeth both including up and down sides (Figure 51).
The upper half of the tooth is called as dental crown while the lower half (covered with gingival) is called as dental root. The inside structure of one tooth roughly consists of four parts. Both dental enamel covering the surface of the dental crown and the dental cementum covering the outer surface of the dental root belong to ectodermal tissues, corresponding to both skin and nail in human bodies. The dentinal matrix located inside of these parts can be classified as mesodermal tissues, corresponding to muscles and bones. The dental pulp located in the central part contains nerves and blood vessels, besides being filled with immature and active cells which perform daily vital activities (Figure 52).




Figure 51
Teeth rows and kinds of teethAdult teeth
consist of 8 kinds of teeth, bilaterally amounting to 32 teeth both including up and down sides.





Figure 52
Cross section of tooth