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 RK61 B72 The care of the 
 
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HARVARD HEALTH TALKS 
 
 THE CARE AND FEEDING OF 
 
 CHILDREN 
 
 BY JOHN LOVETT MORSE 
 
 PRESERVATIVES AND OTHER 
 
 CHEMICALS IN FOODS: THEHl USE 
 
 AND ABUSE 
 
 BY OTTO FOLIN 
 
 THE CARE OF THE SKIN 
 BY CHARLES JAMES WHITE 
 
 THE CARE OF THE SICK ROOM 
 BY ELBRIDGE GERRY CUTLER 
 
 THE CARE OF THE TEETH 
 BY CHARLES ALBERT BRACKETT 
 
HARVARD HEALTH TALKS 
 
 - 
 
HARVARD HEALTH TALKS 
 
 THE CARE OF THE TEETH 
 
 BY 
 
 CHARLES A. BRACKETT, D.M.D. 
 
 PROFESSOR OP DENTAL PATHOLOGY IN 
 HARVARD UNIVERSITY 
 
 1 wd iiiii!;' 
 
 ^ip^ 
 
 CAMBRIDGE 
 
 HARVARD UNIVERSITY PRESS 
 
 1915 
 
COPYRIGHT, 1915 
 HARVARD UNIVERSITY 
 
 S>7TL 
 
HARVARD HEALTH TALKS 
 
 PRESENTING the substance of some 
 of the public lectures delivered at 
 the Medical School of Harvard Univer- 
 sity, this series aims to provide in easily 
 accessible form modern and authorita- 
 tive information on medical subjects 
 of general importance. The following 
 committee, composed of members of 
 the Faculty of Medicine, has editorial 
 supervision of the volumes published : 
 
 EDWARD HICKllNG BRADFORD, 
 A.M., M.D., Dean of the Faculty of 
 Medicine, and Professor of Orthopedic 
 Surgery, Emeritus. 
 
 HAROLD CLARENCE ERNST, A.M., 
 M.D., Professor of Bacteriology. 
 
 WALTER BRADFORD CANNON, A.M., 
 M.D., George Higginson Professor of 
 Physiology. 
 
THE CARE OF THE TEETH 
 
THE CARE OF THE TEETH 
 
 THE importance of this subject needs 
 no argument. Symmetrical, sound, 
 well-kept teeth are important contri- 
 butions to the beauty of the human 
 countenance. Their possession is right- 
 ly construed to mean cultivation and 
 refinement. A person with nicely kept 
 teeth may be expected to be of the 
 kind fastidious in other particulars. 
 Then in addition to the beauty of the 
 teeth, may be urged their importance in 
 the preparation of the food for digestion 
 and assimilation. All other things being 
 equal, the person who masticates his food 
 thoroughly is the person likely to be 
 blessed with the most comfortable and 
 complete digestion, and the best nutri- 
 tion. 
 
 While it is true that the prosthetic 
 dentist is able to provide excellent sub- 
 
HARVARD HEALTH TALKS 
 
 stitutes for the natural teeth when these 
 have been lost, they are not like the 
 teeth which nature makes. In a sense 
 they are comparable to the artificial con- 
 trivances with which we replace natural 
 limbs. They are an added care. In many 
 mouths it is not possible to give them 
 a good fixation; and their efficiency 
 in mastication is much less than that 
 of natural teeth. 
 
 An important circumstance with ref- 
 erence to the possession of good teeth is 
 hereditary influence. The laws of trans- 
 mission from parent to child which ob- 
 tain in other particulars exercise their 
 influence upon the characteristics of the 
 teeth. Children that are born of parents 
 with poor, soft, rapidly-decaying teeth 
 are likely to inherit similar dental pecu- 
 liarities. Conversely, children born of 
 good parentage, whose teeth have been 
 regular, little inclined to decay, and gen- 
 erally strong, are likely to possess teeth 
 resembling those of their parents. 
 10 
 
CARE OF THE TEETH 
 
 Next after the matter of heredity are the 
 circumstances surrounding the early life 
 of the child. This is true with reference 
 to the child's entire environment, — its 
 home life, its fresh air, its outdoor exercise, 
 its sleep, and especially its diet. If these 
 particulars of the home life are wisely 
 controlled, the teeth of the children share 
 in the benefits. If there is ignorance and 
 a lack of proper regard for these things, 
 and especially if such ignorance is added 
 to a bad heredity, it is only natural that 
 we should find, as jve do find, that the 
 teeth of the children are poor, soft, in- 
 clined to decay and apt to be lost early. 
 
 I had these facts forcibly impressed 
 upon me through having been for a time 
 in my early studies in dentistry in a 
 manufacturing city in Massachusetts, 
 having a population including many not 
 of the most favored class. A great num- 
 ber of the parents were of foreign birth, 
 and the ancestry of the children was 
 often mixed. The homes in which they 
 11 
 
HARVARD HEALTH TALKS 
 
 lived, and the general circumstances of 
 their lives, were unfavorable. A con- 
 siderable portion of their diet was made 
 up of a poor quality of baker's bread and 
 molasses, a combination not only lacking 
 in nutritional elements important for the 
 teeth, but also readily fermentable; and 
 the products of this fermentation are es- 
 pecially harmful to the teeth, as we shall 
 see a little later. Among those children, 
 I have many times seen the teeth of the 
 temporary set at the age of four years 
 little more than a mass of decaying roots 
 in suppurating gums, — a deplorable 
 condition, in every particular, for the 
 child's well-being. 
 
 From this manufacturing city I went 
 to begin the practice of dentistry in the 
 place which has since been my home, — 
 a residential city including, particularly 
 in the summer, many who possess in 
 large measure what are usually called the 
 advantages of life. In this community 
 I came immediately and directly in con- 
 12 
 
CARE OF THE TEETH 
 
 tact with a class of people diametrically 
 opposite to that which I have just de- 
 scribed. They were people whose stock 
 was vouched for by that distinguished 
 success in life which gave them their 
 accumulated large means, with its asso- 
 ciated cultivation. In these families 
 the homes of the children, the regimen 
 under which they were brought up, the 
 food which they had, the fresh air, out- 
 door exercise and the abundance of sleep 
 which were provided for them, had their 
 legitimate consequences in a quality of 
 teeth and a healtK of mouth the very 
 opposite of those which I had seen in the 
 other city. The result, in each instance, 
 was but the natural consequence of the 
 operation of influential causes. 
 
 Perhaps I can best speak next of the care 
 of children's teeth, of the reasons why 
 children's teeth should have good care, 
 and of how that care should be given. 
 
 is 
 
HARVARD HEALTH TALKS 
 
 It is essential for a child's well-being 
 that its first teeth be in a state of com- 
 fort and serviceableness, and that they 
 be retained in their places until the per- 
 manent teeth are ready to succeed them. 
 If a child has open, sensitive cavities in 
 its teeth, they are a source of suffering, 
 of discomfort and incapacity in chewing; 
 and if these cavities are permitted to pro- 
 gress until there are exposed pulps, there 
 is ordinarily pain, from which the child 
 may suffer extremely, and which, espe- 
 cially when occurring at night, will be 
 a marked source of disquietude in the 
 family. Then if the child, on account of 
 neglect of its teeth, and the development 
 of penetrating caries with its associated 
 pain, prematurely loses teeth, especially 
 any of the back teeth of the temporary 
 set, there is very likely to be irregularity 
 in the permanent set as a result. 
 
 The teeth of the child, the temporary 
 teeth, are ordinarily in their place at the 
 age of three years. Contrary to the ideas 
 
CARE OF THE TEETH 
 
 generally held among parents, none of 
 these teeth fall out until nature has 
 brought into their places the four largest 
 and strongest teeth of the permanent set. 
 The child's set of teeth is twenty in 
 number, ten in each jaw, five in each 
 quarter of the mouth. The first teeth of 
 the permanent set to appear are almost 
 invariably in place, in a position imme- 
 diately behind the farthest back teeth 
 of the child's set, at the age of six years. 
 These established, nature replaces one of 
 the five temporary teeth in each quarter 
 of the mouth each^ear in this order : — 
 the central incisor at the age of seven ; 
 the lateral incisor at eight; the first per- 
 manent bicuspid succeeds the temporary 
 first molar at nine; and the second bi- 
 cuspid, the second temporary molar at 
 ten; and the cuspids are changed at the 
 age of eleven. These are approximate 
 ages with, of course, some considerable 
 variation in the cases of different indi- 
 viduals. The second permanent molar 
 
 15 
 
HARVARD HEALTH TALKS 
 
 appears at about the age of twelve, and 
 the third molar, or wisdom tooth, at six- 
 teen or at any time thereafter. 
 
 Bearing in mind what I have said of 
 the appearance of the first permanent 
 molar at the age of six, while the tooth 
 which comes into place immediately for- 
 ward of it, replacing the temporary sec- 
 ond molar, is not due until the age of ten, 
 and remembering the fact that any tooth 
 in the back of the mouth has a marked 
 disposition to move forward if there is 
 any opportunity for such motion, it fol- 
 lows that if the temporary second molar 
 is prematurely lost the six year molar 
 moves forward into the space rightfully 
 belonging to the second bicuspid, so that 
 when the second bicuspid is ready to 
 appear four years later, the room to 
 which it is rightfully entitled has been 
 largely appropriated by the six year mo- 
 lar. This leads to a crowding and irregu- 
 larity of the teeth about the front of the 
 mouth which is deplorable. Irregularity 
 
 16 
 
CARE OF THE TEETH 
 
 of the teeth is a thing to be regretted, not 
 only on account of its unsightliness, but 
 because it facilitates the inception of 
 several diseases destructive to teeth. 
 Nowadays instead of " irregularity " of 
 the teeth dentists prefer the term, mal- 
 occlusion. This takes cognizance of the 
 fact that the right relations to each other 
 of the teeth in the opposing jaws is of 
 material consequence for the proper per- 
 formance of the function of mastication. 
 If at the time of eruption the teeth do 
 not come into then; right relationships 
 with each other it is desirable that the 
 dentist's aid be sought early. There is 
 among those who make a specialty of 
 correcting malocclusion, orthodontists 
 as they are called, a consensus of opinion 
 that it is better to make teeth grow into 
 their right positions than it is to under- 
 take to put them there after they have 
 been for a considerable time in wrong 
 relations. The orthodontists also hold 
 as cardinal doctrine that, with rare 
 
 17 
 
HARVARD HEALTH TALKS 
 
 exceptions, all of the teeth should be 
 preserved; in other words, that no teeth 
 should be extracted "to make room," and 
 that the dentist should not undertake 
 to improve upon nature's normal type. 
 
 A related matter of supreme conse- 
 quence is the condition of the child's 
 throat. Throat obstructions of every 
 kind, such as enlarged tonsils and ade- 
 noid growths, especially the latter, are a 
 serious interference with the child's well- 
 being, physically, mentally, and, as is 
 now believed, morally. They often 
 cause mouth-breathing; and with all the 
 rest of their mischievous influence have 
 much to do in making deformities in the 
 face and jaws and in the positions of the 
 teeth. Orthodontists, with other special- 
 ists, insist that children's throats should 
 be made clear. Doing this contributes 
 vastly to their health in many ways. 
 
 To the conditions mentioned should be 
 added an important fact with reference 
 
 18 
 
CARE OF THE TEETH 
 
 to the development of teeth, applying 
 also to development generally, — that 
 precocity ordinarily means a poor quality 
 of development, while tardiness in the 
 development and eruption of teeth has 
 usually associated with it excellent qual- 
 ity. It happens in a few instances that a 
 baby is born with one or two teeth in 
 sight, and that it follows up this charac- 
 teristic of premature development in all 
 of its dentition. Such teeth are almost 
 invariably of poor quality and much in- 
 clined to decay. Nature's capacity for 
 building at the time these teeth were 
 prematurely formed was so limited that 
 she could not do her best work. On the 
 other hand, teeth that are tardily formed 
 and tardily erupted are, as I have said, 
 usually strong and resistant. 
 
 In order that we understand something 
 of the philosophy of the good care of the 
 teeth, it is desirable that we know some- 
 thing of their constitution, their make- 
 
 19 
 
HARVARD HEALTH TALKS 
 
 up. The teeth are, in a sense, dermal 
 structures; that is, like the hair and the 
 nails, they might without much stretch- 
 ing of the fact be called modified skin. 
 The mucous membrane, which lines all 
 of the orifices of the body and is reflected 
 upon a considerable portion of the inte- 
 rior chambers and passages, is but a 
 modified skin, an internal skin, it might 
 be called. Histologically, skin and mu- 
 cous membrane are practically identical. 
 They are each made up of epithelial cells, 
 and the differences between skin and 
 mucous membrane are differences made 
 by differences of environment. The skin 
 is exposed to the air, accustomed to fric- 
 tion, has ordinarily a dry surface, while 
 the mucous membrane is more or less 
 protected from atmospheric action and 
 does not receive the dry friction to which 
 the skin is accustomed. This fact is 
 shown in a sense in the interchanged 
 characteristics of skin and mucous mem- 
 brane, if either, through any abnormality, 
 20 
 
CARE OF THE TEETH 
 
 becomes subjected to the environment 
 of the other. We shall see a little later 
 a significance of this skin-origin, if we 
 may call it so, of the teeth. 
 
 The teeth are developed in an invo- 
 luted pocket, or cul-de-sac, of mucous 
 membrane. At first all of that which is 
 to become tooth is made up of soft tissue 
 so invested. Without going into the 
 minutiae of tooth development, we may 
 accept the fact that the hard tissues of 
 the teeth are constructed by a process 
 of calcification, or in other words, by the 
 deposition of lime salts in this matrix 
 of soft tissue which had preceded. The 
 cells that are the actual builders of 
 the dentine are called the ondontoblasts. 
 The development of what is spoken of 
 by dentists as the dentine, the bone of 
 the tooth, begins upon the periphery 
 of the organ of formation, and proceeds 
 progressively from without inwards. A 
 cross section of dentine is like the cross 
 section of a tubular boiler. It is made 
 21 
 
HARVARD HEALTH TALKS 
 
 up of a multitude of microscopically fine 
 tubules having a packing of what is 
 called the intertubular substance, and 
 containing something which has the 
 capacity of conveying sensation. The 
 most powerful microscopes which have 
 ever been made are unable to demon- 
 strate the penetration to any consider- 
 able distance, except in rare instances, 
 of nerve tissue into the dentinal tubules; 
 but all who have had a sensitive cavity 
 prepared for filling will testify that some- 
 thing exists in the constitution of the 
 dentine, which has a lively capacity for 
 conveying sensation. This construction 
 of dentine, while it is largely completed 
 by the time the tooth has fully erupted, 
 attaining its place among its fellows in 
 the jaw, continues to go on slowly 
 through life. 
 
 That which is spoken of commonly as 
 the nerve of the tooth is made up partly 
 of nervous tissue, but it includes also 
 arterial and venous capillaries for the 
 
 22 
 
CARE OF THE TEETH 
 
 nutrition of the parts, with connective 
 tissue as a packing material. Inasmuch 
 as but a portion of this substance is 
 nerve, it is more accurate to speak of 
 it as the pulp of the tooth. From what 
 we have just seen, the pulp was origi- 
 nally as large as the completed tooth, 
 minus the enamel, and the cementum 
 which covers the root; and what is usu- 
 ally spoken of as the nerve, or as we 
 say, the pulp, is but the remains of the 
 formative organ, and is the main de- 
 pendence of the formed tooth for its 
 nutrition continuously through life. It 
 grows somewhat smaller through addi- 
 tional calcification about the periphery. 
 In people of advanced age the pulp 
 becomes extremely attenuated, almost 
 obliterated. 
 
 The enamel of the tooth begins to form 
 at the same place where the formation of 
 dentine commenced, and goes on pro- 
 gressively from within outwards, so that 
 the construction of enamel is finished at 
 
 23 
 
HARVARD HEALTH TALKS 
 
 the surface. A cross section of enamel 
 reveals a construction of six-sided prisms 
 of great resisting capacity when the for- 
 mation is perfect. As a matter of fact 
 this construction of enamel is imperfect 
 in multitudes of instances. Calcification 
 of enamel begins on the prominent parts 
 of the teeth crowns, the cutting edges of 
 the incisors, the points of the cuspids 
 and bicuspids, and the eminences of the 
 molars. In the bicuspids and molars it 
 progresses from the eminences laterally 
 down into the valleys, the sulci of the 
 teeth, and there is supposed to unite 
 so completely as to form an unbroken 
 sheet of enamel over the entire crown. 
 If the formation is perfect, this is what 
 has taken place; but, as I said, in multi- 
 tudes of instances, the enamel formed 
 from these different centers fails to co- 
 alesce at what should have been the 
 point of union, and there remains a fis- 
 sure or seam of imperfect construc- 
 tion. 
 
 24 
 
CARE OF THE TEETH 
 
 Now as we are studying the matter of 
 preservation of the teeth, we need to get 
 an understanding of what are the great- 
 est dangers to which the teeth are ex- 
 posed. These dangers are principally 
 two: first, dental caries, what is popu- 
 larly known as decay of the teeth; and 
 second, diseases of the investments of 
 the teeth, by which teeth in themselves 
 often intrinsically good, are lost. 
 
 In the first place, with reference to 
 dental caries, a disease of universal prev- 
 alence so far as civilized people are con- 
 cerned, and familiar to every one of us. 
 The matter of causation was studied 
 through the lives of many generations 
 of men without the attainment of any- 
 thing like full and positive knowledge 
 upon the subject. As in the investiga- 
 tion of many other things which have 
 been for a time uncertain, knowledge has 
 been gained step by step, until within 
 the last quarter of a century we have 
 come to what is practically a full under- 
 
 25 
 
HARVARD HEALTH TALKS 
 
 standing of what are the influences that 
 occasion the decay of teeth. 
 
 We have seen that the hard tissues of 
 the teeth are made up principally of salts 
 of lime, largely the carbonate and phos- 
 phate of lime. This means that they are 
 susceptible to the influence of chemical 
 action that may attack constructions of 
 salts of lime, or in other words, they are 
 susceptible to the action of acids, and 
 may be destroyed by such action. In- 
 deed, a French investigator, the late 
 Doctor E. Magi tot, as the result of a 
 good many experiments which he insti- 
 tuted, arrived at the conclusion that den- 
 tal caries was a purely chemical solution 
 of the lime salts of the teeth in acids. 
 But there was a fallacy in Magitot's 
 conclusions for the reason that in his 
 experiments he did not duplicate condi- 
 tions as they exist in the mouth. He 
 did produce disintegration of enamel and 
 dentine by the action of acids; but that 
 is not dental caries as it exists under 
 
 26 
 
CARE OF THE TEETH 
 
 natural conditions. To grasp the whole 
 etiology of dental caries, we need to take 
 cognizance of the constant and practic- 
 ally inevitable presence of multitudes of 
 microorganisms in the tooth environ- 
 ment. The mouth is an ideal culture 
 chamber, — in its temperature, in it's 
 moisture, in its abundance of acceptable 
 nutrition, and in all the environment 
 which it provides for germ life. These 
 microorganisms are of many varieties. 
 For our present purpose, we may speak 
 especially of those which have a capacity 
 for the induction of fermentation. As 
 you doubtless know, ordinary fermenta- 
 tion is inevitably dependent upon the 
 presence and the life activities of micro- 
 organisms of certain types. Without the 
 presence of these microorganisms, no fer- 
 mentation of this kind is possible. These 
 are truths that in their practical mani- 
 festations and demonstrations are more 
 or less familiar to all of us, — perhaps 
 prominently so in the fermentation or 
 
 27 
 
HARVARD HEALTH TALKS 
 
 souring of certain articles of food, as for 
 instance milk, and fruits and vegetables 
 of various kinds. Advantage is taken of 
 this knowledge of the function of micro- 
 organisms in inducing fermentation of 
 different substances, to counteract, by 
 various expedients, the operation of 
 microorganisms, as for instance, by 
 heating to a germicidal temperature a 
 substance that is to be preserved, with 
 or without the addition of sugar or 
 other agencies that have the quality of 
 preserving the substances. If any food 
 material be absolutely sterilized in its 
 fresh and wholesome condition and then 
 be sealed from contact with micro- 
 organisms, its preservation, practically 
 unchanged, is a thing accomplished for 
 indefinite time. Familiar examples of 
 fermentation are the fermentation of 
 wine, of beer, of cider. As you know, 
 there are various and successive kinds of 
 fermentations to which such products 
 
 28 
 
CARE OF THE TEETH 
 
 are subject, each bringing about its own 
 type of change. 
 
 Bear in mind that in that class of fer- 
 mentations with which we are now con- 
 cerned, a factor prominent in the results 
 of fermentation is the formation of acid. 
 This is shown by the at least partially 
 synonymous use of the term " souring " 
 for fermentation. We say that the apple- 
 sauce has fermented, or has soured; and 
 everybody understands. 
 
 Wherever life exists something is con- 
 sumed, something is transformed; some- 
 thing which is aAvaste product for the 
 organism first concerned is developed. 
 And this waste product is often of far 
 more consequence as a disease producer 
 than the microorganisms themselves. In 
 other words, in many cases it is the pto- 
 maines that induce the disease, as it is 
 the microorganisms that produce the pto- 
 maines. This indirect mischief -making 
 of the microorganisms obtains to a large 
 extent in tooth diseases, as we shall see. 
 
 29 
 
HARVARD HEALTH TALKS 
 
 Perhaps some people still hold to the 
 supposition that the microorganisms pro- 
 ducing these changes, particularly the 
 changes in the mouth, are animal para- 
 sites, that is, that they are in themselves 
 minute animals. This is an error. Al- 
 though we may sometimes jokingly 
 speak of the " bugs " in the mouth they 
 are not " bugs." With extremely few 
 exceptions the disease-producing micro- 
 organisms flourishing in the mouth and 
 in the other regions of the body are be- 
 lieved to be in their nature and constitu- 
 tion vegetable and not animal. They 
 are a particularly simple and minute 
 form of vegetable life, and they may be 
 compared to some of the other low forms 
 of vegetable life plainly apparent to the 
 ordinary senses, such as lichens and 
 mosses. Just as we may see patches of 
 moss growing upon a ledge of rock, parti- 
 cularly in a damp place and upon a stone 
 surface not exposed to much friction, we 
 find that these microorganisms of the 
 
 30 
 
CARE OF THE TEETH 
 
 mouth have a capacity of forming among 
 themselves colonies of millions of indi- 
 viduals, constituting a " plaque," and 
 attaching or agglutinating themselves to 
 the tooth surface, with the result that 
 the tooth surface to which they are 
 attached undergoes disintegration on 
 account of their presence; just as we 
 shall find if we detach the moss from the 
 ledge that there are visible evidences of 
 some disintegration of the rock surface 
 on account of its having contributed 
 to the support of the moss. It is an 
 illustration of th& great fact that it is 
 impossible to get something out of noth- 
 ing. 
 
 This analogy between the moss on the 
 rock and the bacterial plaque on the 
 tooth should be studied a little further. 
 It is an old saying that " A rolling stone 
 gathers no moss." This is rightly taken 
 to be an impressive, emphasized state- 
 ment of figurative truth, through the 
 assertion of a physical fact so patent that 
 
 31 
 
HARVARD HEALTH TALKS 
 
 no one could think of disputing it. The 
 impacts and friction to which the rolling 
 stone is subject keep it free from attach- 
 ments of parasitic life, — keep its surface 
 clean. Almost as positively as this, we 
 can say that the tooth surface which is 
 habitually well frictionized will be kept 
 clear of adhesions of mischief -making mi- 
 croorganisms, and will not suffer from 
 disintegration and decay. Indeed the 
 rule applies more emphatically to the 
 tooth than to the stone, because in the 
 tooth the friction acts as a stimulation 
 to the natural constructive powers to in- 
 crease the strength of the resistance, and 
 dead stone has no such powers. I shall 
 revert to this matter later. Putting the 
 teeth to real service in chewing food that 
 requires earnest mastication, their proper 
 function, is markedly for their advantage. 
 Disuse, or little use, invites disease. 
 
 These things have been rehearsed in 
 order to help in understanding what are 
 
CARE OF THE TEETH 
 
 the disintegrative influences upon teeth 
 in the mouth. 
 
 Having before us these matters of 
 tooth constitution, of the chemical 
 nature of the teeth, of existing imper- 
 fection in the formation of the teeth, of 
 the presence in the mouth of various 
 fermentable substances, and also of the 
 existence there of millions of micro- 
 organisms capable of inducing fermenta- 
 tion, we have a grasp of a large part of 
 the causation of tooth decay. 
 
 The assertion may be made that a 
 clean tooth never decays; and this comes 
 very near being strictly true. So far as 
 comes to my mind it is completely and 
 positively true, if we explain that by a 
 clean tooth, we mean one that is materi- 
 ally, physically, chemically, and bacteri- 
 ologically clean. Compliance with these 
 conditions should eliminate dental caries. 
 
 Now we turn aside for a moment to 
 make a division into two classes of all cav- 
 ities occurring in teeth. You remember 
 
 33 
 
HARVARD HEALTH TALKS 
 
 what I said about imperfections in the 
 formation of the enamel of the teeth, 
 — the pits and fissures and seams and 
 imperfect \ places in the teeth, which 
 make interruptions in the continuity of 
 the enamel sheet. When I was speaking 
 of such things, I might have stated that 
 illness, particularly of the exanthema- 
 tous type, occurring in young children 
 at the period in their life history when 
 the teeth are undergoing the process of 
 calcifying, often leaves its marks in the 
 shape of grooves or a row of pits trans- 
 versely upon the teeth, occasioned by 
 nature's modified capacity for construc- 
 tion during the illness. These are com- 
 parable to the marks of imperfection in 
 the formation of the finger nails, often 
 apparent after severe illnesses in adults. 
 It is like the flaw in the weaver's web if 
 the shuttle does not pass as it should as 
 the web is being advanced in the loom. 
 We make our first great group of cavities 
 in the teeth include those cavities which 
 
 34 
 
CARE OF THE TEETH 
 
 have their initiation in the fissures of 
 original imperfect formation. They come 
 very largely upon what are called the 
 grinding surfaces of the molars and in 
 the valleys of the bicuspids. Here the 
 process of decay is invited and facilitated 
 in ways which we are about to see. We 
 put in our second group of cavities those 
 which are formed upon surfaces of teeth 
 where the original construction involved 
 no imperfection. In this second class of 
 cavities, we shall find almost invariably 
 a disadvantage of environment which 
 made the attainment of any good degree 
 of cleanliness a much more difficult thing 
 than in the case of surfaces that are 
 freely exposed to friction. Practically 
 speaking a tooth surface receiving from 
 mastication or any other circumstance a 
 good deal of friction is thereby exempted 
 from an attack of caries. 
 
 Now, bearing in mind these circum- 
 stances of unfavorable environment, of 
 untidiness, of accumulation of debris 
 
 35 
 
HARVARD HEALTH TALKS 
 
 of food, of oral fluids little moved or 
 changed and really stagnated, we are 
 prepared to come back to our theory of 
 causation of disintegration of teeth by 
 decay. 
 
 This debris accumulated around the 
 teeth is acceptable and congenial pabu- 
 lum for multitudes of microorganisms 
 which flourish there, and as a result of 
 their life history produce acids. Just as 
 we have seen the souring of milk from 
 the presence of an acid-producing micro- 
 organism, we may see a like process tak- 
 ing place in the mouth with like results; 
 and the acid thus formed directly upon 
 those surfaces of the teeth less exposed 
 to friction begins a process of disintegra- 
 tion of enamel which is the first step in 
 the formation of cavities which come 
 upon tooth surfaces where there was no 
 original defective formation. This means 
 that cavities of what we are calling the 
 second class come in between the teeth 
 especially if there are places in which 
 
 36 
 
CARE OF THE TEETH 
 
 food habitually lodges and is permitted 
 to remain. Such cavities come also at 
 the necks of teeth, at the margin of the 
 gums, if there is not tidiness and care in 
 the removal of the remains of food. They 
 are especially likely to come about the 
 third molar or wisdom tooth on account 
 of the general unf avorableness of the en- 
 vironment. Often these teeth are not 
 fully erupted. They may remain for 
 years only partially through, not yet oc- 
 cupying their right places, with possibly 
 a flap of the gum partially overlapping 
 them and making a pocket for the reten- 
 tion of particles of fflod and other debris. 
 The cheek often lies in close apposition 
 with the surface of the tooth, and in all 
 particulars the environment is most un- 
 favorable. To this is often added ineffi- 
 ciency in the means of cleaning, when 
 the tooth brush is not made to reach so 
 far back as these teeth. This is very 
 largely the explanation of the popular 
 idea that the wisdom tooth is the poor- 
 
 37 
 
HARVARD HEALTH TALKS 
 
 est tooth in the mouth. As a matter of 
 fact, being formed last, when the tooth- 
 building powers of the system are at 
 their best, the wisdom tooth is frequently 
 very well constituted ; but it is the unfor- 
 tunate victim of its surroundings. In 
 numerous instances it is more sinned 
 against than sinning. 
 
 After the action of the product of mi- 
 croorganisms, and note that I say the 
 action of the product of microorganisms, 
 because no microorganism in itself has 
 any capacity to attack and disintegrate 
 tooth substance, and remembering the 
 physical and chemical make-up of 
 enamel and dentine, we are prepared to 
 see that the conjoined action of micro- 
 organisms and acid constitute the active 
 agencies in the production of decay. As 
 a matter of fact, no microorganism is so 
 small as to be able to penetrate into the 
 sound dentine. They are all too large 
 to be accommodated within the diameter 
 of the dentinal tubule. When the den- 
 
CARE OF THE TEETH 
 
 tine has undergone softening by the acid 
 action, the microorganisms are able to 
 penetrate the tubules, and do penetrate 
 them and carry on the process of fer- 
 mentation with the result of acid forma- 
 tion in the cavity of decay. Thus it is 
 that the more organisms, the more for- 
 mation of acid, the more acid formation, 
 the more disintegration of lime salts, the 
 more softening of the dentinal tubules, 
 the more penetration of organisms with- 
 in the tubules, all together pushing on 
 the process of disintegration and decay. 
 
 Now, leaving this, let us consider the 
 other great class of oral diseases whose 
 action occasions the loss of many good 
 teeth, namely, disease of the investments 
 of the teeth, disease of the gums, disease 
 of the bony sockets of the teeth. This is 
 often spoken of as recession of the gums, 
 spongy gums, elongation of the teeth, 
 loosening of the teeth, or by other such 
 names. There are various popular 
 
HARVARD HEALTH TALKS 
 
 names for it, and various other names 
 used by dentists. A designation a good 
 deal used is " Riggs' disease." This 
 term is in recognition of the part which 
 the late Dr. John M. Riggs, of Hart- 
 ford, took about forty -five years ago in 
 pointing out a considerable share of its 
 true pathology. It is called by dentists 
 pyorrhoea alveolaris, which means liter- 
 ally, a flow of pus from the alveolus, 
 that is, from the tooth socket. It is 
 spoken of sometimes as interstitial gingi- 
 vitis, which signifies inflammation within 
 the substance of the gums, sometimes as 
 phagedenic percementitis, which means a 
 wasting inflammation about the roots. 
 It is an affection whose causation, al- 
 though partially understood for a good 
 many years, has not been thoroughly 
 comprehended until very recently; and 
 it is no doubt true that we have not yet 
 come to understand all that is to be 
 learned and that we ought to know about 
 this disease. 
 
 40 
 
CARE OF THE TEETH 
 
 Dr. Riggs' own theory of it was that 
 it was very largely due to accumulations 
 of foreign substances, such as are popu- 
 larly spoken of as tartar, about the teeth. 
 This formation is ordinarily greatest 
 upon those tooth surfaces situated oppo- 
 site to the openings of the ducts which 
 bring saliva into the mouth, or in other 
 words upon the lingual aspect of the 
 lower front teeth and the buccal side of 
 the upper molars. 
 
 The saliva may hold in suspension 
 salts of lime chemically resembling the 
 salts of lime which constitute a large 
 part of the teeth. These salts are likely 
 to be deposited upon any hard stationary 
 surface which may be in their way. The 
 deposit of tartar ordinarily begins at the 
 margin of the gum in positions not well 
 exposed to friction, and gradually in- 
 creases, extending itself upon the exposed 
 portion of the crown of the tooth and 
 insinuating itself under the margin of 
 the gum upon the root, occasioning irri- 
 
 41 
 
HARVARD HEALTH TALKS 
 
 tation and extending farther and farther, 
 until it loosens the attachment of the 
 gum to the tooth, induces a marked 
 congestion and chronic inflammation of 
 the soft tissues with morbific discharges, 
 including, in deep-seated cases, the con- 
 stant production of pus. There also 
 appears in these deep-seated cases some 
 loss of vitality of the thin margin of the 
 bony socket of the tooth, the alveolus; 
 and this may progress in connection with 
 the other recession and may go on until 
 nearly or quite all of the socket has 
 vanished. The tooth becomes extremely 
 loose, and either falls out of itself, or 
 becomes so troublesome that it is pur- 
 posely removed. 
 
 It has been the theory of our English 
 professional friends that in this disease, 
 the primary disturbance was in the bony 
 tissue of the margin of the socket; and 
 that the other manifestations, including 
 the deposit of calculus, were to be classed 
 among consequences rather than causes 
 
 42 
 
CARE OF THE TEETH 
 
 of the disease. I have no doubt that 
 there is a very small percentage of cases 
 in which this is true, cases of caries and 
 necrosis of bone and of mercurialization ; 
 but the general truth of our own ideas 
 about it appears to be supported by the 
 undenied fact that, practically speaking, 
 the disease always vanishes promptly 
 when the teeth with their attached de- 
 posits are removed. 
 
 Another theory with reference to the 
 cause of this affection is the microorganic 
 theory. Without any manner of doubt, 
 there are numerous cases in which micro- 
 organisms do have a part in carrying for- 
 ward the affection. This would seem to 
 be proved by the fact that in numbers 
 of cases the use of autogenous vaccines 
 prepared from cultures from the indi- 
 vidual mouths, or even stock vaccines 
 of microorganisms of types having much 
 to do in causing suppuration, is often 
 followed by most gratifying results in 
 mitigating, if not curing, the disease. 
 
 43 
 
HARVARD HEALTH TALKS 
 
 Very recent discoveries appear to show 
 in a large proportion of these cases the 
 presence of pus-producing parasites, 
 animal in their nature, which may be 
 killed by a specific germicide. From 
 limited experience the claim is made that 
 this treatment in connection with the 
 proper instrumentation goes far toward 
 relieving the trouble. 
 
 Another causative factor in this affec- 
 tion is believed to be inefficiency, incom- 
 pleteness or tardiness in the elimination 
 of waste products, especially through 
 the alimentary canal, and the kidneys. 
 Habitual costiveness, the undue reten- 
 tion within the system of waste material 
 which should have been rejected, with- 
 out doubt leads in some cases to a vi- 
 carious elimination in which the mouth 
 suffers. A similar statement may be 
 made about the failure of the kidneys 
 to carry out of the system those wastes 
 which it is their proper function to 
 excrete. 
 
 44 
 
CARE OF THE TEETH 
 
 One thing that is absolutely sure 
 about this disease when it has once be- 
 come deeply established is that it can 
 never cure itself or come to an end spon- 
 taneously, with anything short of the 
 loss of the teeth. Another sure thing 
 is that in any treatment of the trouble 
 which, the dentist institutes there can be 
 no real success unless that treatment in- 
 cludes the thorough removal of all con- 
 cretions from the surfaces of the teeth, 
 and especially and emphatically from 
 those surfaces of the teeth that are be- 
 neath the gum. 
 
 There are most important relation- 
 ships between tfhese mouth diseases and 
 systemic diseases of a variety of types. 
 In many cases the mouth disease stands 
 in a causative relation to the other dis- 
 ease; but those are things which we can- 
 not include in this study now. 
 
 One other general fact should be 
 brought into the reckoning; and that is 
 that the habitual chemical quality of the 
 
 45 
 
HARVARD HEALTH TALKS 
 
 oral fluids has a good deal to do with this 
 matter of caries and also of deposits upon 
 the teeth. It is believed that the chem- 
 ical condition of the oral fluids is in- 
 tended to be slightly alkaline. It should 
 at least be neutral. If it is slightly alka- 
 line there are therein advantages. One 
 of these is that the food in the process 
 of mastication and insalivation is satu- 
 rated with a fluid somewhat alkaline and 
 is thereby the better prepared for stom- 
 ach digestion, a process carried on largely 
 by the gastric juice, which has marked 
 acidity as one of its characteristics. A 
 further advantage, and one of great 
 practical consequence in connection with 
 our present study, is that this alkalinity 
 gives protection for the teeth from the 
 action of acids to which they are fre- 
 quently exposed, such as, for instance, 
 the acids of condiments and of many 
 fruits, like apples, peaches, oranges, 
 grapes, strawberries, etc. Whenever 
 there is produced by these things the 
 
 4G 
 
CARE OF THE TEETH 
 
 sensation of the teeth being " set on 
 edge " the explanation lies in the super- 
 ficial corrosion and irritation by the 
 acid. 
 
 The dentist often sees, particularly in 
 the case of young girls who are not fully 
 developed, and are perhaps overworking 
 in school, or combining with their work 
 too great devotion to society, with late 
 hours, and making various mischievous 
 inclusions in their diet, mouths that 
 show unmistakably the habitual pres- 
 ence of acidity. Associated with that 
 acidity are almost inevitably to be 
 found the ravages of extensive decay, 
 extreme sensitiveness, and an entire 
 absence of calcareous deposits or tartar. 
 In such a case more can be done for 
 the well-being of the teeth by elimi- 
 nating the unhygienic factors in the 
 patient's life and by building up the 
 general health, getting nature's functions 
 established, maintaining a proper regi- 
 men in all particulars, and especially by 
 
 47 
 
HARVARD HEALTH TALKS 
 
 antagonizing the acid condition, than 
 can possibly be accomplished by the 
 dentist in his operations of filling cavi- 
 ties alone. 
 
 More rarely there may be such ex- 
 treme alkalinity of the oral fluids, such 
 a superabundance of lime salts held 
 in suspension, that there become at- 
 tached to the teeth great quantities of 
 calcic concretions from which it is ex- 
 tremely difficult to keep them free. 
 These are in no way a menace to the 
 tooth structure itself. They do not 
 cause decay; but their influence is likely 
 to be in the direction of causing Riggs' 
 disease. In antagonizing hyperalkalin- 
 ity we do not know how to do directly 
 and safely very much with chemical 
 agents, for the reason that the constitu- 
 tion of calcareous concretions is chemi- 
 cally so similar to the constitution of the 
 teeth themselves that whatever is cap- 
 able of attacking one is likely to attack 
 the other. 
 
 48 
 
CARE OF THE TEETH 
 
 Now, without following this any fur- 
 ther, we have compassed, I am sure, an 
 understanding of what agencies are very 
 powerful workers against the well-being 
 of the teeth, and have had at least sug- 
 gestions as to what are helpful measures 
 to use in their preservation. 
 
 All of these considerations point to the 
 fact that the intelligent use of agencies 
 for maintaining a good degree of cleanli- 
 ness of the teeth is of great consequence 
 in attaining freedom from disease, and 
 in antagonizing th£ influences that tend 
 to the disintegration and loss of the 
 teeth. The faithful and intelligent use 
 of a brush of proper quality, not too 
 hard and not too soft, supplemented by 
 such dentifrices and mouth washes as 
 may be useful in particular cases (not 
 the same for all people), with the use of 
 silk drawn between the teeth to cleanse 
 the surfaces most in need of cleaning and 
 most susceptible to decay, are our main 
 
 49 
 
HARVARD HEALTH TALKS 
 
 reliances. When conveniently possible 
 they should be used after eating, parti- 
 cularly after the last meal of the day. 
 The most important time is before re- 
 tiring at night. If the teeth may not be 
 brushed after some of the meals the 
 thorough rinsing of the mouth may be 
 helpful. 
 
 To this care should be added, of 
 course, if needed, the counteracting or 
 antagonizing, or better still, the preven- 
 tion of acid conditions. 
 
 In the antagonizing of acid we have 
 four principal agents, all of which are 
 useful in various degrees. The first of 
 these is prepared chalk which chemically 
 neutralizes acid. It constitutes the basis 
 of most of the good dentifrices. A sec- 
 ond means of locally antagonizing acid 
 in the mouth is bicarbonate of soda. 
 There are some objections alleged to the 
 use of this remedy; but I believe that 
 they are theoretical rather than prac- 
 tical. As much sodium bicarbonate as 
 
 50 
 
CARE OF THE TEETH 
 
 can be held upon a dime, dissolved in a 
 small glass of warm water and used in 
 rinsing the mouth, is one of the helps 
 in antagonizing acidity. Another good 
 antacid is lime water. Lime is soluble in 
 water only to a very slight extent; and 
 it may be very conveniently prepared 
 for use by first satisfying its affinity for 
 water, or in other words slaking it. For 
 this there should be used a clean piece 
 of board, or something which will not 
 be broken by the sudden development 
 of heat when the lime and water are 
 brought together. Put the mixture in a 
 bottle, and fill with water, and you will 
 always have conveniently at hand a sat- 
 urated solution of lime. This may be 
 diluted somewhat with plain water, but 
 ordinarily need not be much diluted. If 
 made not disagreeably strong, it may be 
 used freely as a mouth wash. It may also 
 be used advantageously as an addition 
 to milk, to facilitate its digestibility and 
 
 51 
 
HARVARD HEALTH TALKS 
 
 avoid curds in the stomach and prevent 
 gastric acidity. 
 
 A fourth and most effective agency 
 for antagonizing acidity is milk of mag- 
 nesia. This is not a thing to be used in 
 brushing and cleaning the teeth; but its 
 use should follow the cleaning agencies, 
 particularly at night, by taking a small 
 teaspoonf ul of the milk of magnesia into 
 the mouth, and with the tongue and 
 cheeks smearing it over the teeth. In 
 this way its influence is very persistent 
 and efficient. 
 
 The teeth ordinarily decay more dur- 
 ing the quiescence of the mouth at night 
 than they do during the day; and this 
 use of magnesia brings the helpful agency 
 into service at the time when it can do 
 the most good. 
 
 To speak a little more about dentifrices 
 — they are almost without exception in- 
 nocent and more or less effective. Some 
 are much better than others; but there 
 
 52 
 
CARE OF THE TEETH 
 
 is little occasion for incorporating in 
 them anything injurious; and those that 
 are produced and sold by reputable phar- 
 macists are almost invariably free from 
 any harmful quality. The street fakir 
 who works a transformation from the 
 unsightliness of the teeth of the gamin 
 probably uses a preparation containing 
 alum or some kind of acid; but such 
 agencies are not likely to be used by in- 
 telligent people. Some of the newer 
 proprietary preparations whose well 
 chosen ingredients are declared, so com- 
 bine germicidal influence with the right 
 abrasive quality atid a capacity for an- 
 tagonizing acids as to make them supe- 
 rior preparations. I suppose that in this 
 place I ought not to make mention of 
 any particular preparation; but I have 
 confidence in the general beneficial in- 
 fluence of the better specimens of the 
 class that I have in mind, not only for 
 their good effect upon the teeth, but as 
 having much influence in lessening the 
 
 53 
 
HARVARD HEALTH TALKS 
 
 pathogenic microorganisms of the mouth 
 and throat, and so contributing mate- 
 rially to the user's well-being in other 
 ways. Special dentifrices and mouth 
 washes for individual needs should be 
 prescribed or provided by the dentist. 
 
 The manner of using the brush in 
 order that good and not harm may result 
 should be mentioned. Occasionally a 
 person with more zeal than discretion, 
 using a stiff brush and a coarse powder 
 with a crosswise motion of the brush 
 over the necks of the teeth, does make 
 mischief. The margin of the gum is 
 fretted and forced back, the softer por- 
 tion of the tooth above or below the 
 enamel border is exposed, and may be 
 materially worn so as to constitute a 
 V-shaped groove, markedly for the 
 tooth's disadvantage. The right way 
 to use the brush is to place it upon the 
 gum and with a half -rotary motion bring 
 it perpendicularly upward upon the lower 
 teeth, downward on the upper teeth, in 
 
 54 
 
CARE OF THE TEETH 
 
 such a way as to avoid this danger of 
 mischief which has just been described 
 as possible in the crosswise motion. With 
 this motion of the brush, not only is no 
 harm likely to come to the soft tissues, 
 but the cleansing of the teeth will be 
 much more efficient through the passing 
 of the bristles of the rightly trimmed 
 toothbrush between the teeth, than 
 could possibly be the case if the crosswise 
 motion were used. The bristles of the 
 brush should not be set together too 
 compactly, and they may well be 
 trimmed so as to give the brush a ser- 
 rated face. m 
 
 Of course, when we are considering the 
 means of preserving the natural teeth 
 we have to include the dentist's services. 
 In the arrest of dental decay by the pro- 
 cess of rilling, in antagonizing disease of 
 the investments of the teeth through the 
 removal of foreign deposits, and in the 
 treatment of numerous pathological con- 
 
 55 
 
HARVARD HEALTH TALKS 
 
 ditions as they arise in and about the 
 teeth and mouth the dentist's services 
 are for the average individual absolutely 
 indispensable. No class of men would 
 be more glad to have teeth cease to need 
 repairing than would dentists, just as 
 no other class of men would be so glad 
 to have humanity cease to suffer from 
 general diseases as would physicians. 
 And there is a way of practicing den- 
 tistry which is capable, and has been 
 proved to be capable, of setting aside a 
 large part of the ills to which teeth are 
 heir. This is a system which is spoken 
 of as prophylaxis, which comes from a 
 Greek word which signifies prevention. 
 We are told that in China there is a 
 practice of medicine through which the 
 patient pays to his medical adviser a sal- 
 ary, and this salary goes on so long as 
 the patient remains well. The instant 
 the patient becomes ill the salary stops 
 and stays stopped until the patient is re- 
 stored to health. Dental prophylaxis 
 
 56 
 
CARE OF THE TEETH 
 
 has resemblance to this. The dentist 
 is paid for preventing dental caries and 
 pyorrhoea alveolaris, not for repairing 
 or attempting to repair the mischief after 
 it has been done. As sometimes pursued, 
 this system gives the dentist an annual 
 salary. The dentist on his part, insists 
 on having an opportunity to give the 
 teeth a thorough cleansing and scrubbing 
 once a month regularly. This process 
 commenced in children and persistently 
 followed up, aided by the intelligent 
 cooperation of the patients in maintain- 
 ing cleanliness, does result in the preven- 
 tion of a very large number of decay 
 cavities of our second class, those upon 
 the surfaces where there was originally 
 perfection of formation. You will be 
 the better prepared to believe this by 
 going back to the fact, stated earlier, 
 that the teeth are in a sense modified 
 dermal structures, with many of the 
 characteristics of such structures. One 
 of these characteristics of especial conse- 
 
 57 
 
HARVARD HEALTH TALKS 
 
 quence in the present connection is the 
 effect of friction, of a good deal of fric- 
 tion often repeated. When this comes 
 upon the skin it induces a thickening 
 and hardening, intended by nature for 
 self-defence, like the callosity in the 
 hand of the man who does rough work, 
 and the thickening of the skin on the 
 bottom of the feet. 
 
 If the dentist has the opportunity to 
 begin the application of this system with 
 a stick and pumice stone on all of the 
 tooth surfaces of a young child, and 
 keeps up this process faithfully, there is 
 developed in the tooth tissue, greatly 
 increased hardness and resistive capac- 
 ity. Were people to adopt this system, 
 and were the cavities consequent upon 
 imperfection in formation cut out and 
 filled early there would be practically 
 almost no more occasion for filling of 
 teeth. Pyorrhoeal conditions would be 
 altogether prevented, and there would be 
 maintained constantly a dental and oral 
 
 58 
 
CARE OF THE TEETH 
 
 health beautiful to see and delightful to 
 experience. The visit to the dentist 
 would lose its terrors; and the patient 
 would go to the dental office with the 
 same equanimity as if the visit were a 
 visit to the manicure. 
 
 The other things which I wish to say 
 have regard to popular ideas more or 
 less generally held. One of these is that 
 sweet things occasion a great deal of 
 trouble with teeth. This is very largely 
 an error. Sugar, so long as it remains 
 sugar, is absolutely incapable of harm- 
 fully influencing sound tooth tissue. 
 When not taken in excess and at unsuit- 
 able times and if taken in a way so as 
 to form legitimately a part of the diet 
 to be digested with other food, sugar 
 is not only harmless, but provides ma- 
 terial needed for the nutrition of the 
 body and the maintenance of its temper- 
 ature. The mischief from sweets comes 
 through their supplying a substance that 
 
 59 
 
HARVARD HEALTH TALKS 
 
 is capable of comparatively ready fer- 
 mentation in the mouth and in the 
 stomach. They may be taken in such 
 quantities as to impair the digestion, 
 and to lead to a decided acidity which, 
 if not directly developed in the mouth, 
 is conveyed from the stomach to the 
 marked disadvantage of the teeth. But 
 the accusation which dentists very fre- 
 quently hear parents bring against chil- 
 dren, that the decay of their teeth, and 
 their toothaches are due to the use of 
 sweets, is in most instances injustice. 
 
 Another idea is that the period of 
 gestation and lactation in women is a 
 time fraught with peculiar danger to the 
 teeth. The popular idea, popularly ex- 
 pressed, is that " every child costs its 
 mother a tooth." There is some founda- 
 tion for this belief. The explanation is 
 partly in the extra demand upon the 
 mother's system in the nourishment of 
 the new being during the pregnancy; 
 but probably to a greater extent the 
 
 60 
 
CARE OF THE TEETH 
 
 harm to the teeth comes as a conse- 
 quence of the derangement of the 
 mother's system. Not rarely during 
 pregnancy there is disturbance of di- 
 gestion as manifest in the morning sick- 
 ness. The vomiting of pregnancy has 
 associated with it marked acidity. This 
 prevailing acidity is largely the explana- 
 tion of the lesions which take place in 
 teeth during gestation. In the light of 
 all of the facts presented, there appears 
 the logical deduction that at this period 
 there should be especial care in the use 
 of means to antagonize acid conditions. 
 Another idea^which dentists hear ex- 
 pressed almost constantly is that medi- 
 cines are great mischief-makers for teeth. 
 " I always had good teeth until I had a 
 fit of sickness, and then the doctors gave 
 me so many medicines that my teeth 
 were ruined." This is usually rank in- 
 justice to the physician; and the dentist 
 should be earnest in correcting the pa- 
 tient's erroneous beliefs. Ordinarily the 
 
 61 
 
HARVARD HEALTH TALKS 
 
 troubles with the teeth are due to the ill- 
 ness and conditions associated with the 
 illness, and not to the medicines. Almost 
 all medicines as now used are harmless 
 to teeth; but there are a few that may 
 injure teeth or their investments. When 
 one has included acids, salts from which 
 acids may be liberated, some of the iron 
 preparations and the mercurials, the lat- 
 ter particularly when pushed to the ex- 
 tent of producing salivation, the list is 
 nearly complete. 
 
 There are cases, particularly of children, 
 in which it is desirable to provide the sys- 
 tem with special nutrition for the teeth. 
 An established fact in this connection is 
 that if lime salts are to be supplied in 
 the diet for the good development of the 
 teeth and the bones, they should be the 
 lime salts which are prepared by nature 
 rather than in the chemist's laboratory. 
 Synthetically produced lime salts are not 
 assimilated and appropriated into the 
 
CARE OF THE TEETH 
 
 body; they pass out very largely as they 
 entered; but the lime salts which nature 
 produces, the lime salts in eggs, in meat, 
 in milk and in cereals, are in the shape 
 that nature can assimilate, and appro- 
 priate to the nutrition of the tissues 
 which are formed of such materials. If 
 we are to administer special lime salts 
 it is believed that the lactophosphate, 
 really prepared from milk, is among the 
 most advantageous. 
 
 The maintenance of good systemic 
 health, good digestion, good assimila- 
 tion, good nutrition, good elimination of 
 waste, the proper performance of func- 
 tion generally, has much to do with the 
 health of the mouth and exemption from 
 dental and oral diseases. 
 
 63 
 
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