Part 11 (1/2)
They are not sufficiently large or numerous. If the mouth of a child at this age is examined, it will be seen, that a considerable interval has taken place between the teeth in consequence of the growth and expansion of the face; hence a larger set has become necessary to fill the arch. But it may be asked, do not the teeth grow with the growth of the body? and if not, why is it so? They do not, and for this reason: the important office which these organs are destined to perform requires that they should be composed of a substance too dense and of too low an organization to allow of any subsequent growth and enlargement. Thus the size of the teeth is determined and acquired before they make their appearance through the gums. This being the case, it will be readily seen, that the teeth which would be of appropriate size in the mouth of the infant, would be quite inadequate to the enlarged dimensions of the adult; hence the necessity of a second set, exceeding in number, and size the teeth of the first.
That a necessity also exists at this age, that the weak and delicate teeth of childhood should be exchanged for a set stronger and more durable in their structure, more robust and more powerful, will be sufficiently apparent, if we only recollect the great change which has gradually been taking place in the nature of the food of the two epochs of childhood and adult age.
The second set, or permanent teeth, then, lying under the milk-teeth and hidden in the jaw, undergo in this situation their full developement, before they appear above the gum. This occurrence commences about seven years of age, at which period the first set begin to fall out from their roots becoming absorbed, and no longer retaining their hold of the jaw; to be entirely replaced in the course of a few years by the permanent set, which thus succeeds them. The first teeth of this set which make their appearance are the large double teeth, which emerge from the gum immediately behind the last of the temporary set. Next the two front teeth of the lower jaw fall out, and are succeeded by two others of similar character and form, but of larger size; then the two corresponding teeth of the upper row are cast off, and their place supplied; shortly after the teeth immediately adjoining these; then the double teeth of the first set are exchanged for their smaller successors of the second. The eye-teeth after a time begin to make their appearance; and then more double teeth; making in all twenty-eight teeth, and occupying in their developement from the seventh to the fourteenth year of age. They are not, however, yet complete; for between the latter date and the twenty-first year four more teeth appear, called the wisdom teeth, making the adult set or permanent teeth to amount in all to thirty-two teeth. It should be observed, that whilst this is the most usual course in which this set appear, the line of succession is sometimes different.
THEIR VALUE AND IMPORTANCE.
It would seem almost unnecessary to say a word upon so self-evident a truth, and yet perhaps the full extent of this statement is not generally appreciated. It has not, perhaps, occurred to the minds of all, that upon the right position and arrangement of the teeth the beauty and expression of the countenance much depends. But so it is; for however regular and perfect the general features, if the teeth are irregular or deficient, an unpleasing expression, proportionate to the extent of the displacement, is inevitably produced. Now every mother should be alive to this fact, that she may early apply to the dentist to have any error of the above nature rectified, before it is too late.
On their complete and entire state also depends the perfection of utterance and articulation. The child, for instance, makes no attempt at articulation until it has acquired several teeth; this faculty becomes also exceedingly imperfect during the process of changing them; from this time it continues to improve, until again it is permanently impaired in old age, when they are finally lost. And so again, if a child lose merely a single tooth from the front of its mouth, lisping will result; or if a supernumerary or irregular tooth be present, the articulation will be abrupt and imperfect:--the former plainly showing the importance of the entireness of the series, and the latter, the necessity of regularity in their arrangement and position.
The teeth, however, are chiefly important in relation to the part they sustain in connection with digestion, viz. the mastication of the food.
By this act the food, after being received into the mouth, is mixed with the saliva and broken down, till it becomes of an uniform pulpy consistence, fit for being easily swallowed, and acted upon by the gastric juice on its arrival in the stomach. That due mastication of the food is essential to healthy digestion, which will be promoted or r.e.t.a.r.ded in exact proportion as it approaches or falls short of this point, is a fact so generally known as scarcely to need comment.
Suffice it to add, that, if food be introduced into the stomach unmasticated, the gastric juice will only act upon its surface; and after a number of hours it will be either rejected by vomiting, or pa.s.s on into the intestine, to give rise to cholic, bowel complaints, or flatulence, and very frequently in children to a serious attack of convulsions.
THEIR MANAGEMENT AND PRESERVATION.
IRREGULARITY OF ARRANGEMENT AND POSITION.--Every parent ought to have the mouth of her child inspected occasionally, during the advance of the permanent teeth, that any irregularity in their position or arrangement may be prevented. And it is equally her duty to see to it, that she choose a competent person to do this, since great mistakes are not unfrequently made in this matter, and which themselves become the source of evils far more serious than those they are intended to obviate. ”I have known,” says Mr. Bell, ”no less than eight or even ten firm teeth forcibly removed from the jaws of a child at once, when there was not the slightest reason to apprehend any evil result from their being left alone.” Here there was a most cruel, because unnecessary, infliction of pain, as well as great hazard incurred of seriously injuring the permanent teeth by interfering with the secretion of their enamel. And besides all this there is another and yet greater evil, for, if the temporary teeth be removed, before the permanent ones are so advanced as to be ready to occupy their situation, the arch of the jaw will a.s.suredly contract, and when, subsequently, the permanent teeth are fully formed, there will not be room for them to range in their proper situation. Thus the operation which was intended to prevent irregularity becomes the cause of its occurrence, and that in its very worst form, producing a want of accordance between the size of the teeth and that of the jaw.
The eye-teeth generally occasion most anxiety to a parent, from the prominent position in which they present themselves; but in the majority of cases nothing but time is required to reduce them to their proper station. But, whatever may be the peculiarities of each individual case, the dentist will decide what may be required; only, I would again repeat, do not neglect the occasional inspection of the mouth at this age, if you regard the future comfort and appearance of your child.
THEIR PRESERVATION.--The preservation of the teeth requires attention to several points; the first and princ.i.p.al of which is, to enforce the habit in the child of thoroughly cleaning the teeth by means of water and a brush night and morning, and rinsing out the mouth after each meal. The brush should not be very hard, as it will not only be more difficult to clean the interstices between the teeth, the part in which the tartar[FN#24] is most likely to be deposited, but by its friction, will occasion the gradual absorption of the gum and the exposure of the neck of the teeth. The hair of the brush should be firm and elastic, and not too closely set.
[FN#24] A sort of calcareous substance, which becomes deposited at the roots of the teeth, from a want of proper attention to cleanliness; and, if allowed to remain, will destroy first their beauty, and then the organ itself.
TARTAR.--If there is a tendency to the formation of tartar, then it will be necessary to have recourse to some tooth-powder. Tooth-powders, however, must be chosen with care, as many of them are composed of substances highly injurious to the teeth. ”Many of the tooth-powders which are offered for sale, with the promise of rendering the teeth beautifully white, perform, for a time, all that is promised, at the expense of permanent and irremediable injury to the teeth; for they often contain a quant.i.ty of tartaric or other acid, which effects a gradual decomposition of the enamel.”[FN#25] Prepared chalk is one of the simplest and best tooth-powders.
[FN#25] Bell on the Teeth.
The following form, also, may be used with advantage:--
Prepared chalk, three ounces; Orris root, powdered, half an ounce; Powdered myrrh, half an ounce; Cuttle fish, powdered, one ounce; Essential oil of cinnamon, four drops.--Mix.
The best preservative, then, against the formation of tartar, is to see that the child cleans his teeth thoroughly night and morning with the brush, powder, and water, and also (if possible) that he rinses out the mouth after each meal.