A text-book of dental pathology and therapeutics, including pharmacology : being a treatise on the principles and practice of dental medicine for students and practitioners

Front matter

A TEXT-BOOK

REC

OF

Preface

This volume is designed as a text-book of the principles and practice of dental medicine for the use of students, and as a reference work on applied special pathology and therapeutics for the use of dentists. Accepting the dictum of the advanced teachers of the day, the writer believes that an entirely rational system of dental medicine can have but one basis — namely, the same principles which underlie general medical and surgical practice. The book represents, therefore, an attempt at formulating, from data obtained from every available source, a system of dental pathology and therapeutics of which the several parts shall be in harmony with one another and also with the several collateral sciences involved. The impulse prompting the work was no desire to multiply books, but arose from a conviction expressed by many teachers, that such a volume is needed by students, practitioners, and teachers.

The extent and scope of references may be only partially seen in the numerous foot-note references, space limitations precluding any exhaustive bibliography.

It would be unjust, however, to omit this opportunity to credit two investigators without whose researches this volume would have been impossible : Professors G. V. Black and W. D. Miller, to whom frequent and specific references are made.

The immense development of modern dentistry has brought with it a more rational and convenient grouping of its subjects. The American Text-Books of Operative and Prosthetic Dentistry have already won acceptance, each in its own field. They leave untouched a range of subjects which are naturally cognate, and hence are most advantageously taught in conjunction — namely, Dental Pathology,' Therapeutics, and Pharmacology. The fitness of this grouping is manifest.

Special thanks are due the publishing department of the S. S. White Dental Manufacturing Co. for their liberality in furnishing illustrations ;

6 PREFACE.

thanks for cuts are also tendered G. V. Black, J. S. Marshall, J. L. Williams, Win. Wood & Co., and P. Blakiston, Son & Co.

The author tenders to Lea Brothers & Co. his grateful thanks for the more than liberal spirit exhibited by them in the making of the book ; from beginning to end their course has been one of great courtesy and unbounded generosity.

H. H. B.

Chapter I. General Principles

The study of dental pathology and therapeutics embraces a consideration of such principles of general pathology and therapeutics as find application in the practice of dentistry, and in addition implies and requires an exhaustive investigation into the modifications of these general principles growing out of the peculiarities of anatomical structure and the functions of the parts included in the field of operation. There is, perhaps, no aspect of surgery in which these modifications of treatment, due to anatomical peculiarities, are more marked than in dental therapeutics.

A consideration of the special practice must, however, be preceded by a study of the general disease-processes which affect the tissues of the body ; so that a special application of the knowledge thus gained may be made to render clear the nature of dental diseases and the rationale of their treatment.

The word pathology is derived from the Greek pathos, disease, and logos, a treatise or discourse. Applied in its general sense, it includes a study of the natural history of diseases, their causes, progress, phenomena, and terminations. The word therapeutics is derived from the Greek therapeuein, to take care of, meaning the measures adopted to remedy or remove the changes induced by pathological processes.

Pathology, as has often been stated, cannot be pursued as an independent study, for it is but an expression of other collateral sciences. It is a perversion of the processes found associated witli what are termed living bodies ; in its full and philosophical sense it is morbid biology — an altered physiology. It follows, therefore, as a corollary, that an exhaustive familiarity with the contemporary state of the science 2 17 of physiology is necessary to a clear comprehension of the nature of pathological processes. The more minutely an investigator proposes to examine into pathological states, the more extensive must be his parallel knowledge of physiology. While many phases and features of pathology may be grasped by a student of but two courses, there are problems in modern pathology that test and exceed the resources of the veteran of the physiological, chemical, and pathological laboratory.

Whatever field of medicine or surgery may be under systematic exposition, its study is made more clear by turning to and determining the nature of its logical basis, and proceeding from that as a fixed point. While it is true that pathology is by no means an exact science, for the reason that its mother science " biology " has not yet achieved that position, it is indubitable that year by year it increases in the measure of its exactitude. It is relatively a speculative science when compared with such a science as chemistry, which begins with an approximately fixed unit, the atom, and has, therefore, a corresponding stability of superstructure. A true, exact science, as mathematics, begins with a fixed and unchangeable unit, and is therefore absolute.

The unit of the physiologist, and consequently of the pathologist, is a complexity in itself; it is a substance called protoplasm, of which our knowledge is imperfect and relative ; it follows, therefore, that sciences based upon such a unit will be susceptible to changes and alterations until the knowledge of the accepted unit is as complete as the knowledge the mathematician has of his unit.

A contemporary philosopher has said that the standing disgrace of the science of chemistry is that it has not yet given an analysis of protoplasm. Protoplasm, so far as present knowledge permits a statement, is a viscid substance, which under certain conditions exhibits a sequence of phenomena which the physiologist calls life. Its chemical composition is very imperfectly known ; indeed, the only means available for its chemical analysis are such as destroy the identity of the substance. More than this, a subtle change occurs with the cessation of vital activity ; so that in all probability an analysis of dead protoplasm would not represent the composition of vital protoplasm. As set forth by O. Hertwig, 1 "we must regard protoplasm as a morphological, not a chemical conception ; " " it is not a single chemical substance, complex in composition, but is composed of a large number of different chemical substances which we have to picture to ourselves as most minute particles united together to form a wonderfully complex structure." " Protoplasm cannot be placed under different conditions without ceasing to be protoplasm, for its essential properties in which life manifests itself depend upon a fixed organiza-

1 The Cell, 1895.

BASIS OF PATHOLOGY. 19

tion." l Huxley has well termed the substance " the physical basis of life." The nearest approach to a chemical conception of the substance is that it is a collection of proteids ; and of these substances our knowledge is very imperfect. They consist of carbon, hydrogen, oxygen, and nitrogen, combined with sulphur and phosphorus in enormous molecules. It is known certainly, however, that protoplasm does not behave as a fixed chemical substance.

As studied by the physiologist and pathologist, observations as to its properties are made in defined masses of protoplasm, which exhibit the sum of phenomena called life. A simple mass of protoplasm is studied to determine, as far as possible, the ultimate phenomena relating to vitality. For this purpose an amoeba, the anatomical equivalent of a white blood-corpuscle, is placed under conditions which permit of close and continued observation and where the condition of its environment may be altered to study the effects of such alterations upon the vital processes of the cell. The study of collections of cells is a secondary pursuit. While, as has been stated, protoplasm, or contemporary knowledge of it, is the basis of the sciences of biology and pathology, the actual unit of the sciences is the cell. All reasoning proceeds from this basis, that the ultimate phenomena of life are expressed in cell-life, so that the properties and functions found associated with cells are the underlying data of pathology.

If a drop of water be taken from the sides or bottom of an aquarium, placed on a slide and covered with a cover-glass, and then placed under a microscope with, first, a J" objective, there will be noted at some portion of the fluid a small transparent mass having the appearance of a colorless fragment of jelly ; this is an amoeba. The outline of the mass may have almost any form. At some portion there will be a defined and easily distinguished spot, the nucleus ; at another point a vesicle is seen ; the body of the amoeba appears to contain numbers of fine granules. The nucleus appears more markedly granular than the body of the amoeba. If kept under observation, the amoeba will be seen to change its outlines ; at one or more, and it may be in several places projections like blunt arms or feet are seen to be extending from the amoeba (see Fig. 1). On account of their appearance they are called by the physiologist pseudopodia, from pseudo, false, and pous, a foot — false feet. These changes of amreba p^lseudoform are much varied (Fig. 2). The cell has, there- podia; v, vesicle; n,

n ., n -, . . n ... nucleiis.

tore, the property of altering its form — i. e., it has

contractility. If the temperature of the slide be raised, the movements

1 The Cell, 1895.

GENERAL PRINCIPLES.

of the cell become more rapid, and if raised to a temperature of 55° C. the cell contracts in a round lump ; it responds to stimuli, and has therefore the property of irritability.

Fig. 2.

Amoeboid movement of a white blood-corpuscle of man ; various phases of movement. (Klein.)

When certain solid substances contained in the water come in contact with the amoeba, the latter is seen to flow around and engulf them ; as is shown in Figs. 3 and 4, where the analogue of an amoeba, a

Fig. 3.

Fig. 4.

Leucocyte of a frog from the neighborhood of a piece of the lung of a mouse infected Avith anthrax, about forty-two hours after the piece of lung had been placed under the skin of the frog's back. The leucocyte is in the act of eating up an anthrax bacillus. (Brunton, after Metchnikoff.)

The same leucocyte a few minutes later, after it has completely enveloped the bacillus. (Brunton, after Metchnikoff.)

leucocyte, has taken in bacteria. After a time the ingested body is found to have disappeared ; it has been digested. Evidently the cell must produce a substance capable of dissolving some foreign substances — i. e.,

Fig. 5.

Forms assumed by a nucleus in dividing: a, resting nucleus ; b, skein-form, open stage ; r, wreathform ; d, aster, or star-form ; e, equatorial stage of division ; /, separation more advanced ; g and h, star and wreath forms of daughter-nuclei. (Reduced from Flemming's drawings in the Arch. f. Mik. Anat.)

it has the function of secretion. More than this, the amoeba does not take in substances indiscriminately ; some it rejects.

CELL-REACTIONS. 21

If the observations are continued, it will be noticed that changes occur in the nucleus of the cell. A series of alterations in its figure are noted, as shown in Fig. 5. Two nuclei are formed, and soon the body of the cell divides and two cells appear — the amoeba has reproduced itself. This primitive cell has, therefore, the properties of irritability, contractility, secretion and excretion (as will be seen in later studies), and reproduction ; moreover, it responds to stimuli, as seen on warming the stage.

If the stage be cooled, the movements of the protoplasm are lessened, and when foreign substances come in contact with the cell it fails to encompass them — its irritability and contractility are lessened.

It is noted that some simple cells are attracted and stimulated by light ; others are repelled by it.

If a mild induction (interrupted) current be passed through the water in which the amoeba is, 1 the movements of the cell are checked ; if a strong current be passed, the cell contracts sharply. If a galvanic (constant) current be passed, movement at first ceases, but pseudopodia are extruded toward the cathode and the cell crawls toward that pole.

The cell responds to mechanical stimuli, such as violent shaking, by contraction. 2

If substances such as ether or chloroform are added to the fluid, the irritability of the cell is so lessened that it does not respond to stimuli.

If the supply of oxygen be cut off, or if carbon dioxid be admitted to the fluid, movement ceases and the cell remains contracted.

These examples serve to illustrate that protoplasm responds to stimuli of physical and chemical nature, and that its functions may be altered by substances which are brought in contact with it. Upon these facts depends the practice of therapeutics.

A living organism, it will be seen, has a certain degree of action and function. The general average of its action and function is spoken of as a condition of health. When, from any cause, the functions are raised or lowered from the general average, a condition of disease exists.

Stimulation. — Certain agencies applied to the cell increase its activity ; this is called stimulation. The movements of the cell become more rapid, food-particles are taken in more rapidly and disappear more quickly ; irritability, contractility, and secretion are increased. The cell subdivides, or reproduces more quickly. Increase the stimulation, and the vital activity becomes fretful ; in some cases cell-division is incomplete — the nucleus divides, but not the cell-body. Increase the stimulation beyond this degree, and the wearied cell ceases its movements — refuses to respond ; is paralyzed by overwork.

Sedation. — If the conditions be reversed ; if, instead of applying a

1 O. Hertwig, The Cell. 2 Ibid.

stimulus to the cell, an opposite influence be introduced, the phenomena are reversed.

If the temperature be reduced, the movements of the cell become sluggish ; the body changes its form more slowly and less extensively — i. e., contractility is lessened ; particles taken into the cell remain apparently unchanged ; irritability, secretion, and excretion are lessened ; and, furthermore, reproduction does not occur nearly so rapidly — that is, the cell in contact with sedative influences has all of its activities lessened.

There are two great classes of influences, then, which affect the vitality of cells : stimulation, which, if continued long enough, leads to death through overwork ; and sedation, which, if continued, paralyzes all of the energies of the cell — it is starved to death.

Every cell has a range of resistance to these influences which tend to destroy it, which is fitly termed the resistance of vitality. Disease itself is some alteration in any one or more of these several cell-properties, of irritability, contractility, growth, secretion, maintenance, or reproduction. If any one of these properties is not exhibited, it is said that the cell is diseased.

If a brood of cells derived from one parent be examined, some will be seen to grow more rapidly than others, their movements are more rapid and they reproduce more quickly ; others have sluggish functions and movements.

The cell lives its cycle and reproduces, and the parent is no more, the life being continued in the offspring.

The life and properties of this small mass of protoplasm represent in miniature the primitive functions and life of the highest animals.

The contractility is represented in the motive apparatus of the higher animals.

The reception, engulfing, and dissolving, or casting out, bodies with which the amoeba is brought in contact correspond in the higher animals with the digestive apparatus and process and the excretory function.

The highly evolved irritability is represented in the nervous system of the higher animals.

The movements occurring in and about the vacuole are the progenitors of the circulatory apparatus and all of its adjunct organs.

If the irritability of a simple cell be increased or diminished, it corresponds with a disease of the nervous system, and so with the other functions.

It is essential to the life of a cell that the means be afforded it of continuing the activities called life. First, it must receive a proper food-supply, which includes an abundance of water and such solid substances, either contained in the water or dissolved in it, as are necessary to replace loss of substance in the cell ; these are albuminous substances,

CELL-FUNCTIONS. 23

to replace used-up nitrogenous matters ; carbohydrates and hydrocarbons, to replace the everchanging proportions of carbon and hydrogen of living matter ; and, lastly, the supply of oxygen must be sufficient. The cell must be maintained at a proper temperature. Its waste-products must be removed. If any of these conditions be interfered with, vitality is depressed. The most certain cause of prompt death is an absence of oxygen. Cell-life is maintained largely by a process of oxidation.

In the performance of any vital act chemical change is inevitable ; that is, some portion or amount of protoplasm undergoes chemical alteration ; the substances brought as food by the circulating fluid are built into cell-substance to replace those which are lost ; the setting free of chemical energy by the process of protoplasm breaking down into simpler bodies is manifested in the production of heat.

The oxygen about the cell combines with the products of cell-activity, and changes them into substances from which the cell frees itself — the waste, the products of its activity, is removed. The products of cell-activity are largely acid in reaction, and the increase of acid in protoplasm lessens its affinity for oxygen ; hence in an overworked cell oxidation is sluggish, for the outer portions of the cell have a lessened alkalinity.

It is important that a familiarity with cell-properties be obtained, because the functions of any body are made up of the functions of its cells. As before stated, in the more highly evolved animals special collections of cells and special areas are set aside to perform the functions in which the entire substance of an amoeba participates.

Certain collections of cells are found in which one function is active, the others in abeyance ; thus, large colonies of cells exist in which contractility is the dominant property noted ; these are muscle-cells. Others have but the property of irritability ; these are nerve-cells. Still others develop peculiar chemical functions, and become glandular or secretory cells. Such collections of cells are known as tissues. These special cell-colonies or tissues are built together into defined masses for the performance of their specialized functions. In the development of these masses, means of holding and maintaining the cells in definite mass-forms and provisions for their food-supply and waste-removing apparatus are provided in what are called the connective tissues, binding the cells in definite forms and transmitting their vascular supply (foodand waste-carrier). When thus bound together the tissues are said to form organs.

In studying disorders which may affect any one or more organs, or their parts, the problem becomes apparently complex, but it ultimately resolves itself into a study of the disorders of the cells of the part. A disease may only be evident through disorder of some function, for when the tissue affected is studied no evidence of disease is seen even under the highest powers of the microscope.

Another class of diseases will exhibit changes which have occurred in the anatomy of the part, which prompts the classification of diseases into functional and structural. Functional diseases are those which exhibit no demonstrable alteration in the anatomy of a part. Structural diseases are those in which the anatomical structure of a part is altered.

Definite anatomical changes have been found constantly associated with a more or less constant group of symptoms. The changes are spoken of as the morbid anatomy of a disease.

The pathology of any disease means the morbid physiology through which these anatomical changes are brought about. In the absence of direct anatomical examination of any organ a knowledge that it is not performing its work properly and that its functions are disordered is obtained by noting whatever phenomena are obtainable. These are, in part, what the observer may note through the use of his senses, and by utilizing the resources of physics and chemistry. Knowledge gained by such means is called the objective evidence of disease. Certain facts are elicited by questioning a patient as to altered sensations, the nature and situations of pain, etc. ; these are known as the subjective evidences of disease.

The study of symptoms elicited from the patient by examination and noted in his physical appearance is known as Semeiology, from semeion, a mark or sign.

A special study is made of the influences and conditions through which the functions of the body are disordered ; this is known as Etiology.

It is noted that diseases presenting a certain or an uncertain morbid anatomy and a constant course of symptoms have from their beginning to ending tolerably constant phenomena ; they have each a natural history ; this is called the Clinical History of a Disease.

There are symptoms which are common to many disease-conditions, and others which are associated with but some one distinctive morbid state ; different diseases may exhibit several symptoms in common, and some few, which serve to distinguish the one from the other. The study which deals with that discrimination between groups of symptoms which characterize distinct diseases is called Diagnosis, from Greek dia, through, and gignosko, I know. It embraces a consideration of all of those phenomena which indicate the exact disease-state present.

In the study of the clinical history of diseases it is observed that while each disease has a more or less well-defined natural history, they vary as to the course followed in individuals and the final outcome. It

STUDY OF DISEASE. 25

is observed that there are signs and symptoms which are followed by good or ill results, as the case may be. By these signs and symptoms it may be foretold with some degree of assurance what will be the probable outcome of the disease. The branch of inquiry dealing with this aspect of disease-study is known as Prognosis, from pro, before, and gif/nosko.

It is found that agencies described in the succeeding chapter as disease causes affect tissues and organs in such manner that their physiology is altered and changes occur in their anatomical structure. The occurrence of these disordered functions and structures is attended by signs and symptoms which indicate their presence. The study of these particular features of disease is called Pathogenesis ; while it might be inferred from the etymology of this word {pathos, disease, and gennao, I produce) that it was but another name for etiology, it covers a wider field.

Recognizing by the presence of signs and symptoms that the physiology of one or more organs is disordered, and that probably changes of structure have occurred, the great problem of the healing art is to apply such measures and agencies as shall restore the tissues or organs to their normal condition and function. This branch of medicine is known as Therapeutics, from therapeuein, to take care of, to heal.

Centuries of observation have shown that there are numerous agencies and substances which are capable of producing alterations in the action or physiology of organs ; these agencies and substances are included in what is called the Materia Medica — the materials of medicine.

An increasing importance attaches to that method of studying the feature of the healing art which begins with a knowledge of the exact chemical composition of each substance used, and traces with the utmost care the effects of these substances upon the chemical composition and the functions of organs, and how these effects may be utilized in combating disease ; this study is called Pharmacology.

The method of treating disease which begins with an exact knowledge of the causes of diseases, the significance of their symptoms, and their clinical history, together Avith the nature of the alterations of the physiology of organs which give rise to symptoms, and the reasons and nature of the anatomical changes which result from this altered physiology, and embracing an exact knowledge of the effects of agents in the materia medica, which properties are to be utilized in such manner that the causes, phenomena, and results of disease are neutralized, is called Rational Therapeutics.

Such precise familiarity with the nature of disease, and, upon the other hand, of the action of therapeutic agents, is not a possession of medicine ; although it had been noted and confirmed by years of observation that the application or administration of certain agents is followed by a disappearance of symptoms and of the evidences of disease ; the type of treatment pursued upon this basis is called Empirical Therapeutics.

When it is observed that patients exhibit groups of symptoms which appear as constant features of clinical histories, which are alike, and it is further noted that the causes giving rise to these symptoms are identical, and when, furthermore, examination shows the same organs to be affected in one manner, a distinctive name is applied to describe the condition ; it is known, or designated, as some distinct disease. For example, a number of persons who drink water from a common source are, one by one, affected by diarrhoea and a gradually rising temperature of the body, followed by evidences of debility and general poisoning, which symptoms subside after about three weeks : the patients are said to have the distinctive disease, typhoid fever.

It is preferable, when it can be done, to name a disease to accord with its anatomical and physiological features. For example, chemical examination of a patient's urine shows it to contain albumin ; examined under a microscope it shows what are called tube-casts ; at a later period, dropsy or cedemas (which see) appear, and the patient exhibits evidences of poisoning, and later dies. On examining the tissues of the body it is found that the secretory or parenchymatous portions of the kidney are destroyed ; the disease is designated then as parenchymatous nephritis. This word is derived from parenchuma, the substance of organs, and nephros, a kidney, the termination itis signifying inflammation. This suffix always means inflammation ; for example, inflammation of a joint is known as arthritis, from arthron, a joint ; pulpitis, inflammation of a tooth-pulp, and so on.

Some disorders can only be named from a symptom, as neuralgia, from neuron, a nerve, and algos, pain. The suffix algos always signifies pain in the organ or tissue named in the stem of the word, as odontalgia, stem odont, from the Greek oclous, a tooth.

Pains of a rheumatic character are described by the suffix dynia, from odime, pain, as in pleurodynia, from pleura, the side, and odune, pain.

Pains of gouty origin are named by the suffix agra, a seizure, as podagra, from pous, poda, a foot, and agra, a seizure, which describes gout of the foot. Odontagra would be the name applied to gouty pain in or about a tooth.

Before the diseases or disorders of any tissue or organ can be studied intelligently it is necessary that the student be familiar with the anatomy of the part, as revealed by the scalpel, or macroscopic

STUDY OF DISEASE. 27

anatomy, and as revealed by the microscope, the histology of the organ and the tissues of which it is composed, or its microscopic anatomy. It is necessary that a knowledge of its physiology be acquired; the nature of the work performed, how and by Avhat performed. The nature of the chemical changes which occur in tissues and organs should also be known ; and, finally, the mode of development, the embryology of the tissues and organs, should be studied.

It is customary - in fact, almost necessary — that a disease be studied systematically in all of its bearings. First, What is the definition of the disease ? Secondly, How has it been studied in the past ? — i. e., What is its history ? A study of etiology, or the causes of the disease, follows. Next, What is its semeiology ? — i. e., What are its symptoms ? Next an inquiry is directed to the nature of the alterations in the physiology of the parts involved, and what changes of structure occur — i. e., a study of the pathology and morbid anatomy of the disease. The clinical history is next taken up, and followed by a consideration of its diagnosis ; its prognosis or probable outcome is next adjudged ; and, finally, the questions of How shall the disease be combated? What shall be its treatment?

With an increasing knowledge of the pathogenesis of diseases, it is but natural that it should lead to the study of the rational methods of preventing disease — i. e., their prophylaxis (Greek pro, before ; phulasso, I preserve ; and phulax, a guard). It is manifestly preferable to prevent disease than to permit its onset and treat the condition. Before intelligent efforts can be directed toward the prevention of disease a knowledge of disease-causes is necessary, for the prophylaxis of any disease is the destruction or neutralizing of its causes before they have opportunity to act.

CHAPTEE II.

CAUSES OF DISEASE, GENERAL AND LOCAL.

A disease-cause may be defined as any influence of whatsoever nature which is capable of disturbing the nutritive balance of any portion of the body. That branch of study which deals with the causes of disease is called Etiology, from Greek actios, causes, and logos.

Every living organism and all parts of the more highly organized animals possess the power of maintaining a nutritive balance despite changes in their surroundings ; moreover, they persist as living bodies though assailed by forces which tend to disturb the complexus of phenomena called life, even though these forces do frequently bring about modifications in their capacity for work. All of these threatening influences may be regarded as disease-causes, and an examination of the forces which tend to disturb the natural working of portions of the body will show them to be very numerous ; but, as will be seen later, they may be grouped under a few convenient headings.