Part 11

A still worse evil attaching to insufficient use of the teeth is pyorrhœa alveolaris or Riggs’s disease, which, in conjunction with the deposit of tartar, is the great cause of the premature loosening and shedding of the teeth observed among latter-day civilised peoples. This affection consists of a purulent inflammation of the periodontal membrane, owing to the invasion of it by pyogenic cocci, so that pus wells up on pressing the gum against the teeth. Now, when by a vigorous use of the teeth the buccal cavity is kept well flushed with healthy secretions, the growth of micro-organisms within this chamber is kept down, and when, by the same means, the vitality of the periodontal membrane and adjacent tissues of the gum is periodically stimulated, these tissues offer stout resistance to the invasion of pathogenic organisms; but when, contrariwise, the teeth are little used, the secretions of the mouth are in consequence defective both as to quality and quantity, and the growth of organisms in the buccal cavity is promoted; and when, further, the circulation in the periodontal membrane and adjacent soft tissues is not adequately stimulated by vigorous mastication, their vitality is poor and they offer but a feeble resistance to parasitic invasion. We can thus, I think, safely infer that inefficient mastication is a potent cause of pyorrhœa alveolaris; and the chief cause of inefficient mastication being the eating of soft foods, we must also conclude that the latter practice is chiefly responsible for the disease in question; such foods further predispose to this affection in that they are apt to lodge between the teeth and by undergoing decomposition there to favour the growth of micro-organisms within the mouth. The condition of the teeth and gums among the civilised poor is, alas, little calculated to make us proud of our boasted civilisation--the spongy pus-exuding gums, the lengthening, loose, tartar-covered, carious teeth, and the putrescent breath constitute a damning indictment against our modern system of living on a soft, pappy diet, and not giving the teeth the work for which they are designed. I never examine such a mouth without being impressed with, and I may add oppressed by, this fact.

I am not, of course, contending that pyorrhœa alveolaris only occurs in those who masticate inefficiently; whatever causes an unhealthy condition of the gums and saliva predisposes to it, but it is surely much less common in those who masticate well than in those who masticate ill. Confirmatory of this statement is the fact that it is more frequent in those with irregular teeth than in those with a good bite, who are thus able to put their teeth to more effective use. This affection is very common among the carnivora of menageries as well as among dogs and cats; indeed, one seldom fails to find it in dogs over four years of age, and in old dogs it is generally rampant. Doubtless in all these cases the general conditions of life play some part in the causation of the disease, but I do not think that we can eliminate from it the factor of defective use of the jaws and teeth, for it is certain that dogs and cats are fed largely on pappy foods and are often insufficiently supplied with bones.

_The causation of dental caries._--Dr. Wallace, in his philosophical work on “The Cause and Prevention of Decay in Teeth,” contends that the cause of the prevalence of dental caries is that the natural food-stuffs are, to a large extent, ridded of their accompanying fibrous parts and consumed in a form which renders them liable to lodge and to undergo acid fermentation in the mouth; while from the same cause and the induced conditions the micro-organisms of the mouth lodge and multiply and augment the rapidity and intensity of the acid fermentation. I am perfectly at one with Dr. Wallace in believing that the removal of the fibrous portions of food is the main cause of the prevalence of caries among moderns, and I can hardly doubt that foods so prepared tend to promote caries in the way indicated, but I venture to think that they do this even more by failing to call forth the normal degree of mastication. I cannot but think that if these same soft foods were as laboriously masticated as they would need to be if they retained their fibrous ingredients, dental caries would be much less common than it actually is. I have endeavoured to show how very different the local conditions are in the efficient from what they are in the inefficient masticator--how in the former the jaws and teeth are wont to be well developed, the bite to be good, and the secretions which bathe the teeth to be of a kind calculated to promote their health; and how in the latter an entirely opposite set of conditions is wont to prevail. That it is possible to maintain a fine set of healthy teeth till past middle life on ordinary civilised diet, provided the food be habitually subjected to efficient mastication, is shown in the case of the man already referred to, and by numerous other cases which I have observed.

Since the application of cooking to food there has been a progressive lessening in the work of the jaws and teeth and, parallel with this, a diminution in their size and an incursion of dental caries. Among the anthropoids in their natural state caries is practically unknown, and I think we may conclude that the same was true of man before he learnt to cook. In the pre-agricultural races, such as the aboriginal Australians, the effect of cooking the food is shown in the lessening in the size of the wisdom teeth and of the post-wisdom alveolar ridge; dental caries, though rare among these people, does occur, and especially in the wisdom teeth.[27] In the early agricultural period, owing to the increasing softness of the vegetable food, the jaws and teeth show a tendency to be smaller than in the previous periods; the wisdom teeth are decidedly smaller and more prone to caries, while caries of the other teeth is by no means rare. In the late agricultural period the jaws and teeth often show very decided defects of development, while dental caries is, as we know but too well, rampant.

What has been said concerning the relative prevalence of caries in different diet epochs applies to many other diseases of the teeth; thus, along with the increase of caries, there has been a parallel increase in the prevalence of pyorrhœa alveolaris.

CONCLUDING REMARKS

I have now set forth some of the evils resulting from inefficient mastication. They are many and serious. The immediate evils, such as over-eating, indigestion, adenoids, dental caries, and pyorrhœa alveolaris, are bad enough, but when we consider the secondary evils to which these primary ones give rise,--and I have only mentioned a few of them,--we must come to the conclusion that an appalling amount of misery and suffering may be saved by the simple expedient of inculcating the habit of efficient mastication. How this end can best be accomplished will be considered in the next section.

SECTION IV. From _London Lancet_, August 8, 1903

MEANS OF INSURING ADEQUATE MASTICATION

In order to secure the full advantages accruing from the use of the jaws and their appendages, it is, above all, necessary for them to be adequately exercised during the period of development. If this is done, not only will the tendency to dental caries, adenoids, indigestion, and other evils be greatly diminished, but the masticatory instinct will establish itself as a permanent force, so that the individual will tend for the rest of his life to subject even soft foods to thorough mastication. The tongue, the lips, and the jaws of the newly born child find their natural exercise at the mother’s breast, and we should, therefore, do our utmost to get the mother to suckle her child, the bottle affording neither the same kind nor the same amount of exercise. If, unhappily, we fail in this, we must see that the teat of the feeding-bottle is so constructed as to compel the child to earn his meal by, at any rate, some exercise. This kind of exercise promotes the growth of the tongue and thus of the jaws, especially of the mandible. Directly the infant shows a disposition to bite hard things the instinct should be gratified. We may observe a tendency in this direction as early as the third or fourth month, and it becomes more and more pronounced when, the time for the eruption of the teeth approaching, the gums begin to swell up and to get tender, and saliva begins to flow from the mouth; it is now, more than ever, necessary to provide the child with hard substances on which to exercise the jaws and the gums, and a great deal of the trouble of teething is due to the failure to recognise this fact. What, then, are we to employ for this purpose? I am convinced that it is a mistake to rely solely, or even mainly, upon baubles of ivory, coral, and the like useful though these may be in their way; it is far better to give the child something which is not only hard but nutrient and pleasant to the taste, something which will at one and the same time exercise the maxillary apparatus, excite the gustatory organs, and provide a certain amount of nutriment. To this end we may, as the teething time approaches, give a chop or chicken bone, from which most of the meat has been removed; by powdering the bone with white sugar or salt we may increase its attractiveness. From such bones a good deal of nutriment can be extracted, and this of a kind which is most acceptable to the infant stomach, for it must be remembered that the young human is in the main carnivorous. Indeed, since milk is a purely animal diet, all the mammals must be regarded as essentially carnivorous during the period of suckling, while man, as already observed, from the time he emerged from the anthropoid until he learned to cook his food, was throughout life mainly an animal feeder. Therefore we should not hesitate to allow the teething infant animal food in the form suggested. Chicken and chop bones, yielding as they do before the pressure on the gums, are, moreover, just of the right degree of consistence for the purpose in view, while they afford abundant exercise for the tongue; ivory, coral, and the like are, on the other hand, too hard and unyielding, and lack, moreover, the attractiveness belonging to sapidity.

By thus providing the maxillary apparatus with suitable exercise we shall do much to facilitate the eruption of the teeth and to favour the growth of the jaws and their appendages, including the salivary glands, and so to prepare the mouth for the reception of vegetable food. This should, of course, not be given till the teeth appear. The order in which these make their appearance gives some indication as to the order in which vegetable food should be administered to the child. The first teeth to penetrate the gums are the lower incisors which appear from the seventh to the eighth month; then follow the upper incisors from the seventh to the tenth month. These teeth enable the child to _bite_, but not, be it observed, to _masticate_, for which function the molars are necessary. Now the first molars do not appear till the twelfth or fourteenth month; the second molars not till between the fourteenth and the twentieth month; and it seems to me certain that our primitive ancestors could not have obtained starch in any quantity until they reached this age; at the best, pre-cooking man was but scantily supplied with starch, and such slender supply as he had could only be rendered accessible to the digestive juices by vigorous mastication, which broke up the indigestible cellulose framework in which all vegetable starch is contained; hence, until the young human cut his molars, he had little opportunity of securing any starch. These considerations strongly suggest the desirability of giving but small quantities of starch before the twelfth month, and though the facts, that ptyaline appears in the saliva about the time the first incisors are cut, and that pancreatic juice develops its amylolytic ferment at the same time, show that the digestive organs are ready for the reception of some starch at the seventh or eighth month, yet I believe the quantity should be strictly limited. I am ready to admit that the modern child may have, indeed probably has, a greater power of digesting starch than his remote pre-agricultural ancestor; but even so, I am convinced that we should be on our guard not to over-gorge infants with this substance. Only a small quantity should be given before the twelfth month, and it should be gradually increased up to the twentieth month.

I have said that the pre-agricultural infant was unable to secure starch in any quantity by means of his incisors. These teeth enabled him, however, to obtain some soluble nutriment from fruits, and Dr. Sim Wallace has suggested that the early eruption of the lower incisors is for the purpose of enabling the infant to pierce the outer covering of fruits so as to permit him to extract the soluble contents by suction; and, accordingly, when these teeth are cut we may allow the child to bite at such vegetable substances as apples, oranges, and sugar-cane. The latter is a useful article of diet for children, for it provides soluble saccharide in a diluted form, and it is advisable that the child should receive his cane sugar well diluted, for it must be remembered that before the agricultural period man’s supply of pure sugar was limited to wild honey which, consisting as it does almost entirely of mono-saccharide (grape sugar and fruit sugar), is very easily disposed of by the digestive organs. Nowadays, the less digestible cane sugar (which is a di-saccharide) is very largely consumed in the undiluted state, in which it is apt to set up disturbance. When, however, it is obtained by chewing the sugar-cane, it is diluted both by the water in the cane and by the saliva, and I should like to see children obtain most of their cane sugar in this way.

The consideration of the conditions obtaining for pre-agricultural man not only strongly suggests that the young human of to-day should be given starch in very moderate quantities up to the twelfth month, but it points an even more important lesson--viz., that this substance should be given not, as is the custom, as liquid or pap, but in a form compelling vigorous mastication, for it is certain that early man, from the time he emerged from the ape till he discovered how to cook his vegetable food, obtained practically all his starch in such a form; it cannot too often be repeated that uncooked starch in the natural state, locked up as it is in chambers of indigestible cellulose, has no nutritive value; these chambers need first to be broken up by prolonged and energetic chewing, and in this way much or most of the starch is converted in the mouth into dextrines and maltose, very little passing into the stomach in the crude state to set up disturbance in that organ and later in the bowel. If it is given as liquid or pap it will pass down as starch into the stomach, while if it is administered in a form which obliges the child to chew it properly, not only will the jaws, the teeth, and the gums obtain the exercise which they crave, and without which they cannot develop normally, but the starch will be so thoroughly insalivated that much of it will be converted within the mouth into maltose. How foolish to upset the child’s digestive system by deluging it with liquid starch, and then to endeavour to correct matters by giving the malt extract which the child can and should himself manufacture within the laboratory of his buccal cavity.

Clearly, then, the child should make his first acquaintance with starch, not in the form of a liquid or pappy patent food, but in a solid and somewhat tough form. The best means of achieving this end is occupying my attention, and I hope soon to publish the results of my investigation. Meanwhile, I would point out that hard, well-baked crusts constitute a convenient form in which to administer starch to children. A piece of crust may be put in the oven and re-baked; this not only hardens it but helps to convert the starch into dextrine, which is a stage on the road to maltose. If the crust be then cut into a suitable shape and spread with bacon fat or fresh butter, it constitutes a most agreeable morsel. Later, we may give hard plain biscuits. The same principle should be acted upon during later childhood and youth: we should always give, as far as possible, the starch in a form compelling abundant mastication. Loaves should be shaped so as to give a maximum of crust and a minimum of crumb, and should be baked hard. Such loaves are quite as nutritious as the ordinary ones, and much more digestible, containing as they do an abundance of dextrine and not a little maltose, and compelling efficient mastication, especially if eaten, as they should be, without any fluid. A lady who has the catering for a large number of girls gives the bread in this way, and she tells me that there is keen competition for the most crusty portions.

I do not say that starch in the liquid and pappy form should find no place whatever in man’s dietary at the present day, for this would imply the prohibition of porridge, boiled potatoes, milk puddings, and the like. We cannot put back the hand of time and return to the food of our primitive ancestors, nor is it desirable that we should; but we can, at least, arrange matters so that a large proportion of the starch we consume shall be in a form inviting mastication, such as crusts, stale bread, stale cake, biscuits, and so forth. The less children eat of pastry, or, indeed, of any luxurious foods, the better; if brought up on a healthy dietary and under healthy conditions generally, they will relish their simple fare more than the choicest dishes of the epicure. I do not, I say, object to the child consuming a certain proportion of starch in the liquid or pultaceous form, for if, by bringing him up on a rational dietary, his instinct to masticate be afforded due opportunity to develop he will be likely to subject even soft vegetable food to something like adequate mastication; this will tend to mitigate the evils associated with such food, not only by facilitating the digestion of starch, but by flushing the mouth and promoting the health of the teeth and buccal mucous membrane.

The question how far children should be allowed to crack nuts may here be considered. If the child has been brought up on pappy food, and has in consequence brittle and ill-developed teeth, the cracking of hard nuts will be likely to injure them, and this is _a fortiori_ true if any of the teeth are carious or “filled.” And not only nuts but hard food of any kind, such as ship’s biscuits, may in these circumstances injure the teeth, as many of those who went through the recent South African campaign can testify. But if, on the other hand, the child has from the beginning been fed on coarse, hard foods, so that the teeth have been allowed to grow dense and strong, no harm is likely to ensue from cracking such nuts as filberts and Spanish nuts. If a squirrel or a monkey weighing a few pounds can do so with impunity, surely the young human should be able to also. The cracking should, however, be done by the molars, while such hard nuts as Brazils had best not be tackled at all.

Animal food does not need the same amount of mastication as vegetable food, since it is not digested in the mouth, though some contend that the mixture of proteid with alkaline saliva facilitates its subsequent peptonisation. Cooked animal food is, however, all the better for some mastication, owing to the coagulation of the proteids, and, in order to insure the efficient mastication of meat, fish, and poultry, Dr. Sim Wallace recommends that they should be given in large pieces cut thin. “Flat pieces about one inch square generally _necessitate_ a certain amount of mastication. It is difficult to swallow large flat pieces of meat without mastication, but when finely minced little or no mastication is called forth.” The younger the child the more underdone should the meat be.

EXAMINATION OF THE MOUTH AND ADJACENT PARTS

If a child be brought up on the lines indicated and under healthy conditions generally, it is tolerably certain that the maxillary apparatus will develop normally, that the teeth will be strong and well opposed, and show little tendency to disease; but, inasmuch as the methods advocated are but seldom put into practice, disorders of the teeth, more especially caries and irregularities, are common, and hence with a view to promote more efficient mastication it is always advisable to examine our patient’s teeth.

Each individual tooth should be inspected in a good light for the presence of caries, and careful note should be taken of the “bite,” a normal bite implying not only a proper opposition of the two rows of teeth but the capacity of the lower ones to move freely across the upper; mere vertical movement of the mandible does not constitute efficient mastication. In this connection it must not be forgotten that an unopposed molar is useless for purposes of mastication, and it is by no means rare to find in a mouth several sound unopposed molars which are for this reason absolutely functionless. Nay, more than this, it may happen that teeth, perfectly sound ones, too, far from helping, may actually interfere with mastication; thus, among the poor, we sometimes find all the teeth gone save the upper canines and the lower incisors, and the teeth and gums being alike unable to come into contact, nothing worthy of the name of mastication is possible; it would be far better to be without any teeth whatever, for the toothless gums would then be permitted to come into contact along their entire extent, under which condition they gradually harden and come to be quite efficient grinding agents.

Next the gums, the alveoli, and the roots of the teeth must be examined, especially for the presence of erosion, tartar, and pyorrhœa alveolaris, this latter condition being evidenced by the welling-up of pus upon pressing the gums against the sides of the teeth.