Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them]



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Chapter 11 On The Teeth, Which are also counted as bones 1

[Figures for Chapter 11]


Key to the Figure of the present Eleventh Chapter, and its Characters
In this figure are represented the teeth on one side of the upper and lower jaw. Since the arrangement of either side is the same, it suffices to picture the teeth of one side extracted from the jaws. Should one wish to study the teeth still fixed in the jaws, the figures of the preceding chapter show the lower series, while the third and fifth figures of the sixth chapter show the upper set, and the fourth figure of that chapter clearly shows the sockets into which the teeth are fitted. We have carefully removed the teeth of the upper jaw from the skull that we represented in that figure.

AA The eight upper teeth of the right side.
BB The eight lower teeth of the right side.
1, 2 The two incisors [dentes incisivi] of the right side.
3 The right canine tooth [dens caninus].
4, 5, 6, 7, 8 The five right molars. 2 This numbering is applicable to both the upper and the lower group of teeth. The names of the teeth, like the varying nomenclatures of the other bones, are to be taken up at the end of this Book, as I have decided to reserve for that place whatever names I have so far encountered. 3
C The crown 4 of a molar [corona dentis molaris].
D The sharp edge of an incisor [corona dentis incisivi].
E The middle part of a molar is represented here to show the hollow [cavitas pulparis] observable in the teeth. 5


The teeth have sensation
That the teeth alone of the bones have the power of sensation, Galen testifies at length, adding that he himself was troubled by toothache, and had at that time investigated carefully whether the teeth themselves feel pain. He recognized that a tooth not only feels pain distinctly, but also throbs, not unlike inflamed flesh. 6 Certain soft nerves [nn. sensorii] (S and XX in fig. 2, Ch. 2, Bk. 4), small branches 7 of the third pair [n. trigeminus] of cerebral nerves [nn. craniales], are implanted in the roots of the teeth; it is because of these nerves that we believe the teeth are the only bones endowed with the evident faculty of sensation. Some, disagreeing with Galen, infer that the tooth, since it is a bone, is affected with something short of pain, as when we are compelled to cut away protuberances of teeth with a file, or sometimes to cauterize them with hot iron. But when in the practice of such arts we often discover that they have feeling, and when we recognize that they are particularly troubled by cold, the almighty Maker of things is justly to be praised, who we judge bestowed on teeth alone among all the bones a noteworthy faculty of sensation. 8 For he knew they would often come in contact with things that cut, break, abrade, overheat or chill, or alter them in some other way: all of which things the bones are exposed to in a bare state, quite differently from the other bones. Therefore, if they possessed no power of sensation, a person would in no way be warned by pain, nor would he protect a tooth by removing something harmful before the affected teeth were damaged. 9

The distinction between teeth and the other bones
The teeth are thought to be distinguished from other bones not only by sensation and the fact that they are bare, but also because they are always nurtured more than the other bones, and can grow at any time of life; we believe this especially because teeth opposed to those which we have removed subsequently grow beyond the remaining row of teeth into the space of the extracted tooth, no doubt because they are no longer being worn away by opposing teeth. The other teeth grow as much as they are worn by the act of pulverizing food. 10

The number of teeth
Most often, the teeth [dentes permanentes] are thirty-two in number, sixteen in a row on either jaw, arranged like a perfectly aligned row of dancers. 11 Because the first four (nos. 1, 2, D) cut in opposition, they are called incisors, for they are broad and sharp so as to cut away readily by biting, like a knife, food put in their way, and break it up.



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The Canines
Next, a single canine (no. 3) is set on each side, broad at the base next to the gums but sharp at the end, away from the gums, so that if something is not first cut by the incisors because of its hardness, these will break it up. This name is given them because they correspond to the protruding teeth of dogs (in which these teeth are conspicuous).

Molars
After these, there are five maxillary or molar teeth (nos. 4-8) [dentes premolares et molares] on each side, rough, wide, hard, and large, so as to be able to grind to a smoother state things cut by the incisors and broken up by the canines. If they had been made altogether smooth, the molars would not be suitable for their task, since all things are ground better by uneven and diverse surfaces (the molar tooth is marked C). This is why we see that millstones too, on which grains are milled, when they have become smooth over time by long wearing away, are scored and roughened again. If they were rough but not hard, they would not be of much use, as they would wear out before they pulverized the food; but in fact teeth are the hardest of all the bones. Furthermore, if teeth made rough and hard were not at the same time also wide, they still would not fit the task entrusted to them, since it is necessary to establish on a broad base things which need to be most finely ground. For nothing is ground up by the incisors and canines because of their confined and narrow edge. What if the molars had all these qualities but were at the same time small: would not their use be spoiled by this alone, since we would need too much time to grind and crush our food? 12

How teeth are fixed in the jaws
The teeth are all fixed in the sockets of the jaws like nails; 13 because of their resemblance to animal stalls, the Greeks call these sockets fa/tnia, the Romans praesepiola. 14 These [alveoli dentales] surround and confine each tooth, so precisely holding them in place that thay are not readily moved, not even a little.

Roots of the teeth
The teeth are not fitted to their sockets with the same number of roots: small teeth have a single root [radix dentis], while larger teeth have two and the largest three or four (at the beginning of the chapter we have pictured a typical series of roots). Incisors are attached by single roots. Canines also put forth single roots, which are inserted much more deeply than the incisors’ roots and are larger in proportion to the greater strength of the canines. Among the incisors, the two in the middle are attached by more prominent roots than the two lateral incisors next to the canines, no doubt because the middle pair are wider and larger. Molars vary in respect to their roots: those that are affixed to the lower jaw generally have two roots; those in the upper jaw regularly have three. Yet even these sometimes differ, upper molars having four roots apiece; those below are sometimes discovered to be embedded by three roots, especially the two next to the innermost tooth. Quite often you will see the two upper molars [dentes premolares] next to the canine tooth inserted with only two roots and the three remaining [dentes molares] with three each; similarly, the two lower molars [dentes premolares] next the canine have a single root, and the other three [dentes molares] two roots. You will also observe that the innermost [molaris tertius] are attached by smaller roots than those next to them.

The number of teeth sometimes varies
The number of incisors and canines rarely changes in humans as does that of molars. Sometimes there are five molars on either side, sometimes four; occasionally four occur on the left but five on the right, or contrarily five on the left and four on the right, or four below but five above. This variability occurs most often in the back teeth, which most people call the genuini, though Cicero applied this term to all the molars. 15

Wisdom teeth [genuini]
These [dentes serotini] are the ones that appear for the first time after puberty and sexual activity in humans, often accompanied by the greatest torments. Doctors have little observed this, and they either extract other teeth or they persuade themselves that the teeth are affected by a disorder of the humors and overwhelm the sick with pills and similar medications, although for those suffering the pain no remedy can be applied more helpful than a light excoriation of the gingiva next to the innermost tooth, and sometimes a piercing of the bone. I myself am just now experiencing this, as my thirty-second tooth [molaris tertius] is growing in as I write this in my twenty-sixth year of age. 16 Many skulls found in cemeteries show the same thing, where these posterior teeth lie still hidden as in a sort of hollow, 17 perforating the very thin bone [os alveolaris] with some cusps of their crown [corona clinica]. An extremely hard-working student of anatomy and a most learned young man, Joannes Paulus Guiducius of Urbino, a very good friend of mine, recently showed me such a skull. Aristotle and many others attribute more teeth to men than to women; it is no harder for anyone to test this than it is for me to say it is false, since no one is prevented from counting teeth. Many even predict the length or shortness of life from their number. 18

Hollow space in teeth
The teeth not only perform the functions already stated, but they also assist in the modulation of the voice 19 since they are fashioned from a hard and stony substance having small but noteworthy hollows (the tooth marked E) [cavitas pulparis] inside. These make it possible for teeth to be lighter and more easily to take nourishment. Because of this hollow space, if through an influx of acrid or corrosive humors teeth ever develop cavities which extend to this hollow area, the teeth are very quickly decayed to the bottom of the root.

Dental epiphyses
It must not be omitted that the teeth of children [dentes decidui] are based on incomplete, soft, and marrowlike roots [pulpa dentinalis], and likewise that the portion of children’s teeth visible outside the gums [corona clinica] is attached to the root like an epiphysis. 20 This in fact we learned even as children, 21 when we were accustomed to remove our loose


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teeth and those of our friends, particularly the incisors, with fingernails or a thread tied around the tooth. Indeed, in mules also and many dogs, we regularly see their epiphyses [corona dentis] fall off while the roots are retained. Finally, the greatest care must be taken never to remove the remainder of a child’s tooth that has been accidentally broken, but only the epiphysis, in whose place another [dens permanens] (provided the root be saved) will quickly grow up. It is also highly advisable to notice this too in children, in whom the molars tend to erode and weaken at an early age. In such cases it is worthwhile to extract the epiphyses of the molars (which are not as likely to fall out as those of incisors) so that new ones may grow in their place and the teeth may be preserved whole. For if the fusion of the epiphyses is strengthened with the progress of age, the epiphysis will never fall out; indeed, even by the time of puberty some teeth often have to be extracted root and all because of the damage of decay. 22


Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them]