4' ■rmSzv tea Columbia Winibt^tp in tfje Cif j> of j^eto ^orfe ^cfjool of Bental anb 0tal burger? ^^eference %ihvavp Digitized by tine Internet Arciiive in 2010 witii funding from Open Knowledge Commons http://www.archive.org/details/principlesmethodOOIisc No one ivho has written a book has of himself become what he is; everyone stands on the shoulders of his predecessors; all that was produced before his time has helped to form his life and. soul. — Freytag PRINCIPLES AND METHODS ORTHODONTICS AN INTRODUCTORY STUDY OF THE ART FOR STUDENTS AND PRACTITIONERS OF DENTISTRY BY B. E. LISCHER, D.M.D. PROFESSOR OF ORTHODONTICS, WASHINGTON UNIVERSITY DENTAL SCHOOL; MEMBER OF THE AMERICAN SOCIETY OP ORTHODONTISTS; AUTHOR OF " ELEMENTS OF ORTHODONTIA," ETC. ILLUSTRATED WITH 248 ENGRAVINGS LEA & FEBIGER PHILADELPHIA AND NEW YORK Entered according to the Act of Congress, in the year 1912, by LEA & FEBIGER in the Office of the Librarian of Congress. All rights reserved. PREFACE The introductory study of the art here offered to students and practitioners of dentistry was begun with the intention of furnishing a plain statement of present-day tendencies. But the author soon found it impossible to proceed with- out Adopting a point of view which implied a more or less "independent reconstruction of the existing situation." This necessitated the omission of details which, historically at least, are of great significance. Many of the fundamental facts of the science (which have been appropriated from such cognate studies as anatomy) have likewise been omitted, on the assumption that every student has had adequate previous training in them. Similarly was it deemed advisable to eliminate the description of such technical phases as plaster model con- struction, details of soldering, etc., with which every dentist is conversant and which rightfully belong to the laboratory course. Nor has there been any attempt made to present the more recent discussions and debates with which our journal literature abounds. The dental school course does not permit of, nor does the beginner require, such minute exposition of the subject. In brief, the author presents the volume in that limited sense which its subtitle implies, and with the hope that its pages will prove ])oth interesting and instructive. vi PREFACE The author desires to express his thanks to the pubUshers for the many courtesies shown him during the preparation of the volume; to other publishers and authors for the use of several cuts; and to his friend and collaborator, Dr. M. N. Federspiel, of Milwaukee, for his valuable counsel. B. E. L. Washington TJnivebsity Dental School. St. Louis. 1912. CONTENTS INTRODUCTION CHAPTER I THE STUDY OF ORTHODONTICS Definition and Scope of Orthodontics 17 The Literature of Orthodontics 20 The Practice of Orthodontics 23 The Technique of Orthodontics 26 PART I PRINCIPLES OF TREATMENT CHAPTER II PREPARING THE MOUTH FOR TREATMENT Examination of the Patient 32 The ReUef of Pain 35 Cleansing the Teeth 36 Instruction in Oral Hygiene 37 Treatment of Caries 38 The Extraction of Teeth 40 CHAPTER III KEEPING RECORDS OF THE TREATMENT Written Records 43 Plaster Models 46 Photographs 49 Radiographs 50 VUl CONTENTS CHAPTER IV THE ETIOLOGY OF MALOCCLUSION Definition 52 Classification of the Factors 52 Intrinsic Factors 55 Extrinsic Factors . ... 66 Unknown Factors 77 CHAPTER V THE DIAGNOSIS OF MALOCCLUSION First Principles 80 Definition 83 General Outline of the Anomalies of Dentition 84 Differentiation of the Various Forms 85 Summary 96 CHAPTER VI FACIAL DEFORMITIES DUE TO MALOCCLUSION Normal Variations of the Head Form 97 Abnormal Variations of the Profile 108 Orthodontic Conceptions and Ideals 118 Diagnostic Methods 126 CHAPTER VII THE PROGNOSIS OF MALOCCLUSION Definition 130 General Considerations 131 Special Considerations 133 Clinical Summary 138 CHAPTER VIII THE EVOLUTION OF METHODS Methods of the Past 144 Rise of the Systems 148 Lines of Advance 151 Details of Design 152 CONTENTS JX CHAPTER IX PRINCIPAL ELEMENTS OF MODERN METHODS The Plain Band 154 The Anchor Band 156 The AHgnment Wire 159 Ligatures and Elastics 162 Miscellaneous Accessories 163 CHAPTER X PRINCIPLES OF APPLICATION Forms of Anchorage 164 Stationary Anchorage 165 Reciprocal Anchorage 166 Intramaxillary xlnchorage 167 Intermaxillary Anchorage 168 Extramaxillary Anchorage . 170 CHAPTER XI DETAILS OF APPLICATION The Anchor Band 173 The Plain Band 175 The Alignment Wire 176 Ligatures and Elastics 181 CHAPTER XII PRINCIPLES OF RETENTION Tissue Changes Caused by Tooth Movement 183 Definition of Retention 184 Maintenance of Tooth Position 18G Maintenance of Arch Form 187 Maintenance of Arch Relation 189 X CONTENTS PART II METHODS OF TREATMENT CHAPTER XIII TREATMENT OF MALPOSITION OF THE TEETH Labioversion and Buccoversion 191 Linguoversion 195 Distoversion 198 Mesioversion 201 CHAPTER XIV TREATMENT OP MALPOSITION (CONTINUED) Torsoversion . 203 Infraversion 208 Supraversion 210 Perversion and Transversion 212 CHAPTER XV TREATMENT OF NEUTROCLUSION Simple Neutroclusion 213 Complex Neutroclusion 226 CHAPTER XVI TREATMENT OF DISTOCLUSION Bilateral Distoclusion 245 Unilateral Distoclusion 265 CHAPTER XVII TREATMENT OF MESIOCLUSION Bilateral Mesioclusion 272 Unilateral Mesioclusion 281 CHAPTER XVIII TREATMENT OF MALFORMATIONS OF THE JAWS . . 284 ORTHODONTICS INTEODUCTION CHAPTER I THE STUDY OF ORTHODONTICS DEFINITION AND SCOPE OF ORTHODONTICS Orthodontics is a term proposed by Sir James Murray, the eminent philologist, to cover that branch of dentistry which deals with the principles and practices involved in the prevention and correction of malocclusion of the teeth, and such other malformations and abnormalities as may be associated therewith. Dr. Frederick B. Noyes^ defines it as "the study of the relation of the teeth to the development of the face, and the correction of arrested and perverted develop- ment." It is of dental origin, having been reared by dental practitioners, and is a crowning achievement of the dental progress of the last generation. The terms Orthodontia, Odontorthosia, Dental Orthopedics, and Dental Orthomorphia, which are less acceptable from a linguistic standpoint, are 1 The Dental Cosmos, January, 1911. 18 THE STUDY OF ORTHODONTICS also used. Like general dentistry, orthodontics is a part of the -vast field of medicine, and when we recall "that all sciences which deal with life, with force, and with chemical composition" entej' into the study of medicine, we may fairly comprehend the breadth of its base. Orthodontics as a Science. — As a science it is closely related to many of the medical sciences, the basis of which is biology, the science of life. "Life, that strange, unknown something which flies through the viewless air, flashes through the ocean's depths, blushes in the petals of a rose, and mani- fests itself in thousands of marvellous forms — can science grasp, define, or explain it?" In the present stage of our knowledge probably not completely; but it teaches us that all vital processes, including man and all his characteristics, as well as those of all other species, are the result of the interaction of certain law^s. To define these laws, to test them in the crucible of observation and experiment, and then to express them in terms of human experience — this is the mission of science. Now, the treatment of dental anomalies involves us in countless difficulties, hence "we seek truth not merely for the pleasure of knowing, but in order to have a lamp for our feet. We toil at building sound theory in order that we may know what to do and what to avoid." Thus the jDrocess of dentition, its mechanism, causes, and various develop- mental stages, as exemplified by comparative studies, is not without meaning, but furnishes a field of compelling interest to every intelligent dentist. It is further apparent that a comprehensive knowledge of the development of the jaws, and of the nasal passages and their accessory sinuses (which are so intimately related to them), is also desirable. A frequent attribute of malocclusion of the teeth is a marked inharmo7iy DEFINITION AND SCOPE OF ORTHODONTICS 19 of the facial lines. The true basis of a differential classi- fication of such deformities is a wide familiarity with ethnic variations of the head form. A valuable aid in the study of the various forms of malocclusion of the teeth is an inquiry into the classification of all anomalies, the relations of anomalies to disease, and the foundations of teratology in general. Again, a consideration of the causative factors opens a large field of inquiry to the student of orthodontics, owing to their intimate connection with the theories of inheri- tance, the transmission of acquired characters, and other allied Darwinian factors and biological problems. Another essen- tial to a scientific comprehension of treatment is a careful consideration of the tissues of attachment, i. e., the alveolus and pericementum, and the changes they undergo during and after tooth movement. All these are questions for the scientific orthodontist to investigate, and, if possible, to explain; he must search for the laws underlying them, tell why they are so, and indi- cate the place they occupy in the scheme of things. Finally, to render our studies less difficult, and to perfect the nomen- clature of orthodontics, we must strive to develop a greater accuracy of expression and uniformity of usage of the terms we employ in our speech. The practice of medicine, in any of its branches, consti- tutes a remedial art; for art consists in doing, in the appli- cation of knowledge. "The subject matter of art is life, life as actually is; but the function of art is to make life better. Operations become arts when their purpose is conscious and their method teachable." Orthodontics as an Art. — As an art, orthodontics is con- cerned with the principles and methods of treatment; what these are the present \-olume briefly tries to show. 20 ^ THE STUDY OF ORTHODONTICS THE LITERATURE OF ORTHODONTICS All endeavors to find adequate treatment of our subject in the earliest historic times have been fruitless. Thus, Farrar^ writes of a review b}^ Litch (1839), based upon some four hundred works on dentistry, and all they contained relating to the subject could have been gathered in one volume of moderate size. And though Celsus (a.d. 30) is said to have recommended finger pressure for the correction of malposition of the teeth, we can find no attempts at systematic treatment of the subject until the publication of Fauchard's^ admirable book. The work of this eminent pioneer was not exclusively devoted to orthodontics, but he regarded the subject of sufficient importance to describe various methods of treatment and to dwell upon the etiology of malocclusion. The earliest recorded special work is that by the German dentist, F. C. Kniesel, entitled Der Schiefstand der Zdhne, in the German and French languages, and published in Berlin in 1836. During the interval embraced by the dates of publication of these two books the field of orthodontics was variously treated by dental authors, notable among whom were Bunon (1742), Bourdet (1757), Berdmore (1770), Fox (1803), Delabarre (1806), and Catalan (1808). The joint treatment of its subject matter with other phases of dentistry continued the prevailing custom for many decades, in fact, up to the present. Among the more prominent dental texts that continued thus to treat it are the following : Handbuch der Zahnheilkunde, Linderer, 1842; Systematisches ' Irregularities of the Teeth, vol. i, p. 12. 2 Le chirurgien dentiste, Paris, 1728. THE LITERATURE OF ORTHODONTICS 21 Handbuch der Zahnheilkunde, Carabelli, 1844; American System of Dentistry, vol. ii, Litch — Guilford, 1887; American Text-book of Operatire Dentistry, Kirk — Angle and Case, fourth edition, 1911; Dental Surgery, Tomes, fifth edition, 1906; A Text-book of Operative Dentistry, Johnson — Pullen, 1908. In 1880 Dr. Norman Kingsley, of New York, published the first American text on orthodontics, entitled Oral Deformities. The volume embraced several chapters on malocclusion of the teeth, their etiology, diagnosis, and treatment; besides a consideration of cleft palates and fractures of the maxillae and their treatment. In 1888 appeared the two-volume work of Dr. J. N, Farrar, of New York, entitled Irregularities of the Teeth. These volumes are a veritable mine of orthodontic data, and cannot be otherwise regarded than epoch-making.^ This eminent pathfinder of the art was the founder not only of the "systems," but of present-day methods of treatment. In the meantime, general dentistry was making rapid progress; every department was being influenced by the vast extension of human knowledge during the last half of the nineteenth century. The growth of dental literature was now to proceed, and orthodontics claimed many enthusi- astic workers. It will be convenient to arrange all recent writers according to nationality, and by continuing our discussion of American authors we come to the work of Talbot, Irregularities of the Teeth, fourth edition, 1901. The book is said by its author to be " an outgrowth of researches which tended to oppose the too prevalent theory that irregu- larities of the teeth and jaws were the result of local, not 1 Pfaff, Lehrbuch der Orthodontie, 2d ed., p. 373. 22 THE STUDY OF ORTHODONTICS constitutional causes." Most of us believe this to be extreme teaching; but it should be read, owing to its treat- ment of the subject of degeneracy. Orthodontia, by S. H. Guilford, fourth edition, 1905, has been a favorite intro- duction for many years Malocclusion of the Teeth, by E. H. Angle, seventh edition, 1907, is an exposition of the Angle System, and, like other works published in the last decade, open to criticism because of its exclusive originality of presentation. The works of Knapp, Orthodontia Practically Treated, 1904; of Jackson, Orthodontia and Orthopedia of the Face, 1904; and of Case, Dental Orthopedia, 1908, are treatises of the same group, each volume being a presentation of the author's methods. These remarks, however, are not intended as an index of the relative value of these works, since they contain much that the student cannot afford to ignore. The work by MacDowell, Orthodontia, 1901, concludes the list of American authors. The foreign literature, though not so large, is a creditable showing for a speci^alty as young as orthodontics. In England there is the excellent little volume of essays by Wallace, entitled Irregularities of the Teeth, 1904; and the more pretentious text by Colyer, of the same title, published in 1900. In Germany there is the work of Walkhoff, Die Unregel- mdssigkeiten in den Zahnstellungen und Ihre Behandlung (1891), and the texts by Jung (1906), Pfaff (second edition, 1908), Herbst (1910), and the excellent little manual by Korbitz (second edition, 1911). In France the art is represented by the works of Gaillard (1909), Martinier (1903), and Donogier (1895). Spanish dentists have recently (1909) welcomed a work by Subirana, entitled Anomalies de la Oclusion dentaria y Ortodoncia. THE PRACTICE OF ORTHODONTICS 23 Controversial writings, the reports of cases, and modi- fications of technical details (whose proper place is in the journals) have been liberally })resented b}' dental maga- zines, many of them conducting departments of orthodon- tics.^ In Germany a monthly journal exclusively devoted to the art has recently (1907) been established, entitled Zeitschrift fiir Zahndrztliche Orthoyddie . Much of the recent periodical literature represents the proceedings of societies and scientific associations. In the general bodies, such as State, national, and international societies, sections are frequently organized for the more deliberate consideration of orthodontic problems. Among the societies exclusively devoted to orthodontics, mention may be made of the American Society of Orthodontists, the British Society for the Study of Orthodontics, and the Deutschen Gesellschaft fiir Orthodontic, etc. Thus the art, though hardly out of its teens, has, never- theless, an extensive library; and at its present rate of growth bids fair to equal in content, as well as in volume, the liter- ature of other branches of dentistry. The recent proposal of A. D. Black^ that the profession adopt the Dewey decimal system of classification for dental literature will render available the countless articles in our magazines, covering every phase of the sub ect. THE PRACTICE OF ORTHODONTICS Recent advances in the methodology of the art and the consequent extension of its boundary lines have abinidanth' 1 Items of Interest, New York. 2 Proc. Inst. Dent. Pedagogics, Sixteenth Annual Report. 24 ^ THE STUDY OF ORTHODONTICS justified its separation from general practice in all com- munities capable of supporting the specialist. The many advantages of specialization are so well known that a restatement of them here is deemed unnecessary. Ortho- dontic services by their very nature readily constitute a special and ample field. Hence the point we wish here to emphasize is the dependence and independence of the two fields, their limitations and relations, and to indicate the course one ought to follow if one contemplates the practice of orthodontics. This theme has been the subject for numerous articles in the journals, though rarely has it been so ably presented as in the paper by Dr. Ottolengui, entitled "The Sphere of the Dentist in the Field of Ortho- dontia," from which we quote the following:^ " I respectfully submit it is my view that the best ortho- dontists of the future, as in the past, must be forthcoming from the ranks of such men as begin in the regular practice of dentistry, and gradually choose to practise orthodontia exclusively from a pure love of the work, and especially because of their inherent love for, and patience with, children. "If this be true, it follows as a logical sequence that the dentist has the moral as well as the legal right to practise orthodontia; but he should have no legal right, as surely he has no moral right, to undertake orthodontic work without a full and competent knowledge of the present requirements and technique. Any physician may treat the eye, the nose, the throat, or do any operation in surgery if he has the ability to do so successfully; but he may be mulcted in heavy damages if he attempt such work and fail, because of I Items of Interest, November, 1909, p. 819. THE PRACTICE OF ORTHODONTICS 25 lack of proper training or skill. The medical degree is no protection to the malpractitioner. "It is the same in dentistry. Any dentist may undertake the treatment of malocclusion, but he is guilty of malprac- tice in some degree if he does not first acquire the needed training and knowledge. "The sphere of the dentist in orthodontia is, therefore, to be considered from a dual aspect: (1) The general prac- titioner who elects to treat malocclusion occasionally, and (2) the dentist who decides to refer all such cases to the specialist. The first man should have exactly the same knowledge as the specialist himself. For, if the dentist treat but one case a year, he is morally bound to know how, or else refer the patient elsewhere. "On the other hand, the general practitioner who decides not to treat malocclusion, but elects to recommend a special- ist, should at least inform himself sufficiently of the art to be a competent judge of the success or failure of the specialist into whose hands he takes the responsibility of placing the management of the teeth and jaws of a growing child. For, it should be remembered, there are degrees of excellence in all crafts, and the mere fact that a man may announce that he has decided to 'restrict his practice to orthodontia' does not prove that he is competent." As an additional word of caution, it is well to state that no one should attempt the exclusive practice of orthodontics without adequate preliminary training in general dentistry, because a liberal knowledge in the treatment of the two main groups of oral diseases {i. e., caries and lesions of the pericementum, which can only be acquired in general prac- tice) is absolutely indispensable. It is imperative that we learn by experience what it means to keep a mouth well. 26 THE STUDY OF ORTHODONTICS Finally, when combined with general dentistry (a neces- sity in all outlying districts and rural communities) it will be necessary to so systematize the office routine that a definite number of hours be exclusively devoted to its prac- tice. This should be regarded as a pleasant duty by all conscientious dentists; for it has been estimated that fully 50 per cent, of the children in every community are afflicted with some form of malocclusion of the teeth, which, in the aggregate, means a vast army of countless thousands upon whom, for obvious reasons, the specialist can never smile. And last, but not least, the mastery of orthodontics implies postgraduate study, which the dental hospitals of our larger universities should liberally provide. Such depart- ments are worthy of the most liberal endowments, and it need hardly be emphasized that they should be open to graduate students the year around. THE TECHNIQUE OF ORTHODONTICS Many of the earlier works on general dentistry contained chapters on "Irregularities" and "Regulation," probably because the correction of malocclusion has always been regarded as a function of the dentist. A noteworthy char- acteristic of these texts was the prominence given to the technical phases of the art, the details of appliance con- struction being constantly kept in the foreground. The treatment of malocclusion being a mechanical process, in which technical methods play an exceedingly important part, it seems quite natural that the technique should have been regarded as an important division. Indeed, it is still so regarded; but the dawn of another era is upon us, the THE TECHNIQUE OF ORTHODONTICS 27 day of "home-made" appliances is rapidly approaching its twihght, and an appreciation of greater possibiKties is directing our attention and energy to other problems. The mechanisms of former days were usually manufactured by the operator, which consumed a great deal of his time, and so magnified the details of construction that the principles utilized were frequently lost sight of. The following prophecy from the pen of Dr. J. N. Farrar^ appeared in 1878: "Although the simplification of regula- tion has been a great desideratum for many years, it has for some time been evident to me (though by. most people thought to be impracticable) that the time will come when the regulation process and the necessary apparatus will be so systematized and simplified that the latter will actually be kept in stock, in parts and in wholes, at dental depots, in readiness for the dental profession at large, so that it may be ordered by catalogue numbers to suit the needs of the case; so that by a few moments' work at the blowpipe in the labora- tory the dentist may be able, by uniting the parts, to pro- duce any apparatus, of any size desired, at minimum cost of time and money." That prediction has been fulfilled; orthodontics has passed through its elementary stages, and finally reached as high a degree of development as other departments of dentistry. There was a time when the operator made his pluggers and other instruments, and the prosthodontist his plate gold and solders; similarly was it considered an ortho- dontist's duty to invent and construct the appliances for a case in hand. But after years of ceaseless toil, "of immeas- urable devotion of energy and time and genius" to a most 1 The Dental Cosmos, January, 1878. 28 THE STUDY OF ORTHODONTICS worthy art, certain facts of experience have finally been systematized. Indeed, the whole spirit of effort of the last decade has been a reaction against former methods, and has been characterized by a demand for a new arrange- ment, for some settled principles in the art. A mere heaping together of disconnected, confusing methods has long since ceased to satisfy all serious students. Thus, there comes the concession from all sides that appliances are but the means to an end — the remedies, as it were — with which the operator should so familiarize himself as to master their use and manner of application, not their manufacture. "Systems." — From the standpoint of this new and higher perspective, and in response to the urgent demands of progress, several so-called "systems" have been offered to the profession, every one of which embraces much that is good. But a system, at best, is but a compilation of certain definite principles, elements of design, and methods of treatment, and these rarely are the product of a single mind. It usually represents the results of the separate efforts of several individuals, and may even be compiled for private gain. On the other hand, a system may have a higher motive, and tersely emphasize the advantages of simplicity of tech- nique, or the achievements of unusual skill. Doubtless their influence upon our technique has been salutary, though our resultant methods continue to impose definite technical attainments. Hence, laboratory courses in orthodontics, similar to those of operative and prosthetic dentistry, of chemistry and bacteriology, have become permanent fixtures in the dental curriculum.^ The student frequently under- estimates the importance of this phase of the subject, and 1 Lischer, Elements of Orthodontia, St. Louis, 1909. THE TECHNIQUE OF ORTHODONTICS 29 defers its accomplishments until launched in private prac- tice; when the demands of a growing patronage and the unavoidable difficulties of treatment militate against the acquirement of that special dexteritj^ so essential to success. Moreover, it is immaterial which method of treatment an operator will ultimately adopt — whether it be a system as such, or a combination of several — the technical training enjoined in either case will always be considerable. Thus, the application of appliances for treatment, the accepted methods of keeping records, and the construction of reten- tion appliances demand a very high order of skill; and one arrives at skill only by patient labor, by the practice of an exacting discipline. Let every student of orthodontics remember, therefore, that the laboratory course is always designed for a definite purpose, that it fits well into the plan of things, and that there is no short cut across the plane of accomplishment. PART I PRINCIPLES OF TREATMENT CHAPTER II PREPARING THE MOUTH FOR TREATMENT Surgical cleanliness on the part of the operator and his equipment is the first rule in all operative procedures. Since the founding of bacteriology by Pasteur, and its wonderful development by medical scientists, leading to the discovery of the relations of bacteria to animals in health and disease, it has received a new interpretation. Were it not for the fact that its omission continues the prevailing custom with far too many operators, it would not receive mention here. Indeed, its presentation is hardly appropriate in a work on orthodontics. Following the reception of the patient, the adjustment of the operating chair and its accessories, should come the preparation of the field of operation. In orthodontic prac- tice this has a special significarce, and embraces a number of important preliminary considerations. The aim of these several preliminary details is the establishment of oral health — in so far as this is possible prior to orthodontic treatment — and to facilitate the treatment. 32 PREPARING THE MOUTH FOB TREATMENT EXAMINATION OF THE PATIENT The fundamental importance of a careful examination of every individual applying for treatment need hardly be emphasized, for it forms the very basis of every intelligent diagnosis. A cursory consideration of the general health and physical development of the patient constitutes the first step of such examination. Should any doubt regarding it arise, the patient (or parent) should be questioned and a record made of recent recovery from serious ailment. Such interrogations frequently prompt parents to relate the pres- ence (or removal) of adenoids, and other conditions etio- logically connected with the malocclusion. The attention of the operator is commonly directed toward some "promi- nent" incisor or cuspid, which he will for the present ignore, and consider later in the course of a definite routine. The thorough examination of the oral cavity should now proceed, and include, besides the superior pharynx, the nasal passages and form of the nose; the function of the Hps; the facial lines and expression; the jaws beyond the immediate alveoli; the relative immunity or susceptibility to caries; the condition of the gums and pericementa; the form of the palate; the frena of the lips and tongue; and all surfaces of the crowns of all teeth. Though a differential diagnosis of the malocclusion suggests itself here, it is usually best to defer the same until accurate models have been constructed. Instruments. — The instruments required for an examina- tion consist of a mouth mirror (Fig. 1), of non-magnifying type, with metal handle. A plain, long-handled exploring instrument, of a pattern as shown in Fig. 2, is used for the location and exploration of carious cavities. The use of EXAMINATION OF THE PATIENT 33 Fig. 1 Fig. 2 Mouth mirror. Exploring instiument. 34 PREPARING THE MOUTH FOR TREATMENT floss silk in the interproximal spaces and contact areas is also advised. A tongue depressor of simple design (Fig. 3) is used for the examination of the superior pharynx. Patho- logical conditions of the nasal passages which may stand in causal relation to the malocclusion and require the services Fig. 3 Fig. 4 Tongue depressor. Nasal speculum. of a rhinologist may frequently be detected with a nasal speculum (Fig. 4). A pair of operating pliers and some aseptic absorbent paper, for the drying of tooth surfaces, are useful accessories. All of these instruments should be in readiness upon the operating table, and all unnecessary appliances removed. Finally, a memorandum of all obser- THE RELIEF OF PAIN 35 vations should be made upon a record card conveniently placed upon an adjoining table or desk. The form of this card is described in Chapter III. THE RELIEF OF PAIN The value of early treatment for malocclusion is increas- ingly being appreciated, hence many of the patients in an orthodontic practice are children in whose mouths temporary teeth are still present. And though the treatment of tem- porary teeth is more widely practised than formerly, extensive caries, pulp exposure, and its sequeloB are all too frequently met with. The proper treatment of such conditions should invariably be insisted upon; and in this connection let it be remembered that reckless extraction is not the remedy. Indeed, the exigencies of many cases demand their conser- vation, especially if we view the denture as a whole, and always from an orthodontic standpoint. The disastrous results following the neglect and early loss of temporary teeth will be discussed in the chapter on Etiology. The temporary teeth are frequently the seat of pain, which many of the younger patients fail to mention. "In every instance where there is suffering the manifest duty of the professional man is to relieve it at once if possible, no matter in what form it may present itself" (Johnson). The sub- sequent application and operation of the appliances for tooth movement are of sufficient annoyance to make the above imperative. The student should therefore make a study of the causes of pain and of all therapeutic aids and methods employed for its alleviation. Such service is always appreciated, and goes far in the promotion of con- fidence, 36 PREPARING THE MOUTH FOR TREATMENT CLEANSING THE TEETH Cleanliness and health are synonymous terms in oral hygiene, hence the next important preliminary consideration is a careful cleansing of the teeth. "Dentists are not living up to the highest possibilities of their art when they fail to consider the importance of maintaining the tissues around the teeth in a state of health, and this cannot be done short of a careful removal of all extraneous material which may be found adherent to the teeth." (Johnson.) Probably no two operators will exactly agree as to the instruments to be used and the particular methods to be followed in cleaning the teeth ; but all must agree on the fundamental importance of the procedure. The author is not aware of any definite statistics regarding the matter, but he feels certain that only one patient in every hundred presenting themselves prac- tises oral hygiene to the extent that orthodontic treatment could be instituted without first cleansing the teeth. But aside from the beneficial effects upon the general health of the oral cavity which every cleaning promotes,, it must further be emphasized that appliances are shortly to be adjusted. These are to be securely anchored to a number of teeth, and in many instances remain for a period of weeks, or even months. Upon their removal, after tooth movement has been accomplished, retention appliances are to be inserted for another prolonged period. Not infrequently the anchorage of the latter are upon the same teeth previously utilized. It is obvious, therefore, that only by the utmost cleanliness during the entire period of orthodontic treatment can the health of the oral cavity be maintained and caries of the teeth prevented. INSTRUCTION IN ORAL HYGIENE 37 INSTRUCTION IN ORAL HYGIENE The maintenance of physical vigor is a duty of every human being, and imphes the practice of a rigid personal hygiene. Among its many requirements few are of greater importance than the proper care of the mouth. The vast majority of individuals suffering from dental diseases is incompetent in the practice of an efficient oral hygiene; hence it becomes the duty of the operator carefully to instruct patients in this important detail. The most opportune time for this instruction is immediately after the teeth have been cleansed. It is an opportunity the conscientious practitioner never neglects, and it should always be regarded as an essential detail of a carefully planned routine, because all regulating appliances interfere with the normal functions of the mouth and favor the lodgement of food particles, thus promoting caries of the teeth. Owing to the rapid rise of orthodontics as a specialty, this discussion brings us to the line of demarcation between the fields of the specialist and general practitioner. An orthodontist extends his acquaintance and wins patronage in any one of three legitimate ways; patients are referred to him (a) by the family; dentist, (6) b}^ the family physician, or (c) by a member of the laity. Of course, if the ortho- dontic treatment is instituted by the family dentist there can be no question as to when, or how, and by whom these services are to be rendered — they belong to the general practitioner. On the other hand, if the specialist is consulted, or if the case is referred to him by the dentist, the entire treatment can be rendered with greater dispatch if both can agree on a definite plan, since all of these preliminary 38 PREPARING THE MOUTH FOR TREATMENT services should always be rendered prior to any orthodontic treatment. But the specialist must not underestimate responsibilities during the period his services are being rendered, and in all cases showing a high degree of sus- ceptibility to caries he should encourage the most liberal consultation with the family dentist. TREATMENT OF CARIES All carious cavities, in both temporary and permanent teeth, should be treated prior to tooth movement and in the FiQ. 5 Carious cavities rendered extremely inaccessible by the malocclusion. best manner the conditions will permit. The choice of a filling material is at times rendered difficult, since the factor of accessibility may enter into consideration. Fig. 5 shows an occlusal view of the upper arch of a patient, aged twelve TREATMENT OF CARIES 39 years, with cavities in the right and left centrals and laterals as indicated by a and b. It is obvious that the insertion of gold foil or other permanent repair is out of the question. A plastic like oxyphosphate of zinc is here indicated, and will be protected by bands placed upon the teeth for their movement. After the orthodontic treatment has been completed they will be normally accessible, and will then permit of permanent restoration. In cases of extensive caries, requiring crowns and bridges, the operator must likewise come to a definite conclusion as to the most opportune time for their insertion. Accessi- bility, though still a factor, now gives way to anchorage; for should the affected tooth, or teeth, be required for anchorage of the regulating appliance, they should be restored before orthodontic treatment is attempted. Fortunately, the necessity for such extreme remedial measures is decreasing, and their consideration in orthodontic practice is becoming extremely rare. The author has recently treated a case of bilateral disto- clusion, accompanied by labioversion of the upper incisors, for a boy, aged twelve years, who, owing to an accident result- ing in fracture, had a porcelain crown inserted upon the left upper central during his ninth year.^ The behavior of the root during orthodontic treatment did not appreciably differ from those in which the pulps were vital. Numerous similar experiences, therefore, predicate the conclusion that if caries has progressed so as to affect the pulp, or to a stage demanding an artificial crown, it should receive the custom- ary treatment; that non-accessibility, or extreme malposition, may occasionally postpone the more permanent restorations until tooth movements have been accomplished. » See Case K, Figs. 207 and 208. 40 PREPARING THE MOUTH FOR TREATMENT THE EXTRACTION OF TEETH The subject of the extraction of teeth prior to or during orthodontic treatment divides itself into that (a) of tempor- ary teeth, (6) of supernumerary teeth, and (c) of permanent teeth. Temporary Teeth. — Temporary teeth too extensively decayed to warrant attempts at conservation, and whose retention would seriously affect the health of the oral cavity, should always be removed prior to treatment. But in many instances, especially in the very young, when several years might elapse before the eruption of their successors, every effort should be made to retain them. Again, in cases of arrested development or "contracted" arches, with firm temporary teeth present and postponement of treatment inadvisable, their movement and subsequent retention should proceed with that of adjacent permanent teeth to induce growth of the alveoli and jaws beyond, and to pro- mote the normal eruption of their successors. Extraction is indicated in every case of prolonged retention, provided there are no symptoms of deficiency in the number of perma- nent teeth, or where the successor is in process of eruption. Supernumerary Teeth.^ — Supernumerary teeth should always be extracted, especially when they operate as a cause of malocclusion. It is best, however, to defer all extractions until accurate models have been constructed. Every operator should strive to record as many cases as his practice affords. Permanent Teeth. — The extraction of permanent teeth for the facilitation of the orthodontic treatment is a question regarding which many incisive papers, and more incisive rejoinders, have been written. Prior to the development of our present methods for the correction of arch malrelation, THE EXTRACTION OF TEETH 41 removal of certain permanent teeth was widel}' practised, even regarded as a necessity. But with the perfection of the details of arch movement as well as tooth movement, the group of cases in which extraction is now permissible has been greatly restricted. The literature pertaining to this subject is voluminous, immensely interesting, and of the utmost value, though the following two rules by Professor Guilford^ serve as an excellent abbreviated version of the entire discussion. "1. Do not decide to extract until a careful study and restudy of the case have been made from articulated models and the patient in person, and until every available method of procedure without extraction has been carefully con- sidered." "2. If extraction seems unavoidable, adopt the best method of correction without it, and when, in the course of the operation, it becomes absolutely evident that the desired result cannot be obtained in that way, it will still be time to extract and change our method of procedure." Finally, it must ever be remembered that the loss of even a single tooth produces a break in the continuity of the arch; that the adjoining teeth always tend to move toward the space thus created; that the abnormal inclination of the adjacent teeth is accompanied by loss of contact in more remote places in the arch; that a reduction in the size of the lower arch is frequently followed by a deepening of the "bite" and an increase in the difficulties of retention; and that the harmony of facial form rarely permits of the sacrifice. The numerous clinical phases of this subject can be more appro- priately dealt with in subsequent chapters on the methods of treatment. ' Orthodontia, 4th ed., p. 48. CHAPTER III KEEPING RECORDS OF THE TREATMENT Many of the advances in medical practice have been based upon hospital statistics, where the facilities and methods for keeping records have always surpassed those adopted by individual practitioners. It is, perhaps, not inaccurate to state that in dentistry the reverse is true. Dental clinics, in most instances, are usually conducted for the purpose of furnishing opportunities for experience to students and to serve those in need, being only incidentally utilized as centres of research. It is but fair to add, however, that the hospitals furnishing the largest and most trustworthy mass of clinical data for medicine are not, necessarily, the school hospitals; and that the funds at the command of such institutions far exceed those of the dental infirmaries. For purposes of scientific research it is always advisable to procure clinical data from both public and private records, though under existing dental conditions the private records of practitioners are preferable. It is to be hoped that an enlightened interest in human health and an appreciation of the sociological significance of preventive medicine (which should be provided for all the people by the strong arm of the State) will revolu- tionize this phase of dental service in the not distant future. Now, it is not at all unusual for an average practice to extend over a period of from thirty to forty years, thus affording ample opportunities for the compilation of valuable WRITTEN RECORDS 43 data upon which scientific deductions and advances in treatment can be based. It is exceedingly important, there- fore, that the beginner adopt some plan for the keeping of records, and the points to be emphasized are that such records should be accurate, concise, and practical. When they comply with these requirements, their value can hardly be overestimated. They should be so designed as to provide for the special needs of an orthodontic practice, which may briefly be enumerated as consisting of written records, of plaster models, of photographs and radiographs, and such illustrations or appliances as are deemed worth recording. WRITTEN RECORDS Among the many methods that can be employed for the keeping of written records, a specially designed card system has been found most convenient. It should be of standard size, preferably 5x8 inches, and provided with a filing cabinet so arranged as to permit of comprehensive classifi- cations. Figs. 6 and 7 exhibit the essential items of such a record card. All of the scientific phases of a case, including the patient's name and the case number, are placed upon the face of the card. The reverse side is arranged for the practical phases of the treatment. Several of the items upon the front of the card are compiled from the reverse side after completion of the case, or at the operator's convenience. In addition, the author uses plain ruled cards of the same size as the record for the compilation of all data of scientific interest. These are reclassified by the use of extra guides, and can be compiled by any competent assistant. 44 KEEPING RECORDS OF THE TREATMENT WRITTEN RECORDS 45 46 KEEPING RECORDS OF THE TREATMENT This system of records renders available for immediate use or study all the material his practice affords. For example, it enables one to instantly state the number of patients of any given age, or sex; the number of cases where the influence of a given etiological factor is exhibited in the models, e. g., premature loss of temporary teeth. All models, photographs, radiographs, etc., are numbered and recorded on the record card. Thus all items of interest of any given case, or of a series of cases, can instantly be brought together for comparison and study. The possibilities of the card system are so numerous that it appeals to every operator who values his records at their true worth; it is so elastic in its application that any inquiry or investigation may easily be carried out by its use. PLASTER MODELS In 1756 Ph. Pfaff ^ introduced the use of plaster of Paris for model construction. That its use did not become general, however, is evinced by the fact that Kneisel,^ eighty years later, still relied on sulphur, though both employed wax as an impression material. The latter frequently resorted to the use of metallic models in the construction of his apphances. These were made of fusible alloy and obtained from plaster impressions of his sulphur models. The construction of accurate plaster models of the upper and lower teeth and adjacent parts is now considered a necessary detail of every orthodontic record (Fig. 8), and, as Angle has clearly emphasized, their value is enhanced in ' Zahne des Menschl. Korpers, Berlin. 2 Der Schiefstand der Zahne, Berlin, 1836. PLASTER MODELS 47 proportion to their accuracy. To obtain this accuracy plaster should invariably be used for the impression from which the model is made. When accompanied by written records, they are of the greatest scientific value, especially to the owner who is familiar with many of the unrecorded details of their history. Fig. S A plaster model of a case of malocclusion prior to treatment. Clean, perfect models are an incentive to render better service and mark the dividing line between the amateur and artist. They are absolutely necessary in making an intelligent diagnosis; are useful in a study of the etiology and prognosis; and particularly in planning the treatment and designing the retention appliances. Tootli movement usually extends over a period of several months, and is only 48 KEEPING RECORDS OF THE TREATMENT ultimately successful if adequate retention is provided. The latter is an extremely difficult phase of every treatment, and is practically impossible without the aid of accurate models of the original conditions. No operator can afford to rely on his memory as to the exact nature of these original conditions. Facial deformities are frequently due to anomalies of dentition, and their correction now occupies a large place in orthodontic practice. A record of such service, for which Fig. 9 Plaster models of the face before and after treatment. (After Case.) two methods are at our disposal, is eminently desirable. Professor Case^ recommends plaster models of the facial lines. These may be made in full front and profile views, and are of natural size (Fig. 9). But the construction and filing of these models present difficulties which many operators have sought to avoid. This has given rise to the 1 Dental Orthopedia, Chicago, 1908. PHOTOGRAPHS 49 adoption of the photographic method, a process introduced by Professor John W. Draper, of the University of New York, in 1839. Fig. 10 Shows size of the unmounted photographs and the lines to which they are cut before mounting on the record cards. PHOTOGRAPHS When made according to certain definite requirements, photographic records of the facial hues answer every pur- pose, and for convenience are mounted on cards of the same size as the record. The requirements are simply these: The same photographer should make all photographs of 4 50 KEEPING RECORDS OF THE TREATMENT any given series; he should use the same lens in every case and adopt a uniform size and pose. The prints should always be made upon the same kind of permanent paper, and delivered unmounted. A good plan is to instruct the photographer as to what is wanted, laying special emphasis upon the fact that under no circumstances shall he retouch any of the operator's negatives. To avoid variation in size, particularly in the various prints of any given case, the author has taken the precaution to provide the photographer with a card upon w^hich accurate measurements are marked. It is advisable further to agree on the kind of background to be used, a dark ground being usually best, because it affords the proper contrast. In mounting, many of the unnecessary features of the prints (such as dress, shoulders, hair ornaments, etc.) may be eliminated by using a pattern cut from transparent celluloid, and marking to exact size before cutting (Fig. 10) . All prints of any given case may then be mounted upon a 5 x 8 card, numbered and filed in the cabinet with the records. RADIOGRAPHS In the treatment of malocclusion of the teeth one fre- quently meets with anomalies of number, or of eruption and form. To establish certainty in the diagnosis of such cases the a;-rays (discovered by Professor Rontgen in 1895), in com- bination with photographs, are of the greatest value. Indeed, for the elimination of guesswork they are invaluable, since by their use it is possible to determine definitely deficiency or redundancy in the number of teeth, and to ascertain the peculiarities of anomalies of form and eruption. The difficulties encountered in the movement of teeth may at RADIOGRAPHS 51 times be due to the fusion or malformation of their roots; tardy eruption may occasionally be caused by perverted position; a negative or indefinite history of premature extraction rendered intelligible, instead of construed into Fig. 11 Shows tardy eruption of the right central incisor due to the supernumerary tooth shown in Fig. 12. Fig. 12 vj \\ Radiograph of case shown in Fig. 11. deficiency of number. Many cases might here be introduced to illustrate the wide range of their usefulness, but Figs. 1 1 and 12 will suffice, for they clearly show the presence of a supernumerary tooth as the cause of tardy eruption of the right upper central incisor in a girl, aged eleven years. CHAPTER IV THE ETIOLOGY OF MALOCCLUSION Definition. — In medical science, the study of the origin of disease and abnormahty is termed etiology. It embraces a consideration of all causative factors, and of the provisional theories advocated when the causes remain obscure. And since it is the mission of orthodontics /o prevent, as well as correct, certain anomalies of dentition, it is obvious that all knowledge relative to their causation is of the very first importance. From time immemorial, therefore, observant operators have endeavored to ascertain and remove these agencies, believing this to be the first aim of every rational treatment. Unfortunately, this phase of the art frequently presents problems exceedingly difficult of solution. CLASSIFICATION OF THE FACTORS In order to diminish these difficulties, several authors have attempted a classification of the etiological factors; though a review of the literatur pertaining to this subject impresses one with the fact that a quite general disagreement yet exists. Some writers accept the time-honored division into hereditary and acquired, finding little difficulty in formu- lating definitions for these two terms. Others exhibit a very evident skepticism regarding the "influence of heredity," and thus lean strongly toward the acquired group. CLASSIFICATION OF THE FACTORS 53 Heredity and Predisposition. — Of course, there was a time when heredity explained it all, when it served as a cloak for our ignorance; when most diseases and abnormalities were believed to have been transmitted from parents to offspring. But the ijhysical basis of heredity (a mechanism existing within the germ cell) is now fairly well established. Many of the recent advances in biology have fostered a strong opposition to the old views, forcibly emphasizing the influence of environmental (acquired) factors, which cannot be ignored. "As to the inheritance of the effects of extrinsic forces upon the individual, we find little in the way of direct evidence. Mutilations of any sort are not inherited." (Jordan and Kellogg.) This new^ teaching, it must be admitted, has served as a healthy antidote; it was needed. On the other hand, the claim of the opponents of heredity — "that nature never transmits the abnormal," that all anomalies are but the result of certain lapses in nature's processes, always due to local and extraneous influences — ■ is equally untenable. In the light of modern biological science either view is now considered extreme. Unfortunately, in these days of the "systems," with their truly wonderful achievements in technique, we are prone to rest content with our superficial calculations— for we love to cling to seeming bounds. But accepting, as we must, the physicochemical explanation of life, we are constrained to adopt those causomechanical factors of its flux which are recognized by biologists generally, and w^hich "involve no philosophical assumptions." These are heredity, variation, adaptation, selection, isolation, and (probably) mutation. With the first of these we are here briefly concerned. Heredity may be defined as " the genetic relation between successive generations, as the transference, of similar char- 54 THE ETIOLOGY OF MALOCCLUSION acters from one generation of organisms to another, as a process affected by means of the germ cells." All peculiar- ities or characteristics that are imparted to an individual through these germinal cells of the parents are spoken of as inherited. Any peculiarity that is imparted a'fter conception has taken place is spoken of as acquired. If before birth, it is termed an intra-uterine acquisition; after birth, an extra- uterine acquisition. All inherited peculiarities are also said to be congenital, whether recognizable at birth or not. Likewise, all intra- uterine acquisitions are congenital; whereas extra -uterine acquirements are spoken of as extragenital. The careless use of the term congenital (many writers believing it to be synonymous with hereditary) has been the cause of much confusion. Concerning predispositions, Professor Orth, of Berlin, says: "Every incapacity of the body to resist the external causes of disease, every peculiarity of the constitution which renders the latter unable in the struggle of the body with the cause of disease to maintain the normal course of the vital phe- nomena, every such peculiarity of the constitution may be designated as a tendency, as a predisposition, to disease. All these predispositions to disease must be congenital and inherited, for they are a result of the phylogenetic develop- ment; they have their origin in the general characteristics inherent in the germ cells. This conception of what con- stitutes predisposition to disease does not contain anything mystical; it is not beyond the domain of science, and is just as capable of scientific treatment as any other pathogenetic question, though we must admit that our knowledge of the predispositions to disease does not go much beyond a few generalities." INTRINSIC FACTORS 55 Heredity, therefore, is not as definite a factor as formerly, though we must continue to regard it as of great importance in the study of organic continuity. "Heredity repeats strength or weakness, good or ill, with like indifference." (Jordan and Kellogg.) Furthermore, one phase of this vast theme stands out very prominently, viz., all dental research relative thereto, and thus far conducted, is entirely inadequate. For this reason alone we should pause long before boldly denying its probable "influence" in the causa- tion of malocclusion of the teeth. Another very plausible reason why we should be less hasty in excluding the heredi- tary factors is, that many anomalies of other organs of the body (notably the eyes, e. g., errors of refraction, imbalance of the ocular muscles, etc.) are largely congenital and fre- quently transmitted from generation to generation. Surely, the teeth and jaws are not exempt from the "influences" which control such maldevelopments. "Our present plight seems to be exactly this, we cannot explain to any general satisfaction" all the causes of mal- occlusion of the teeth without the help of some hereditary factors; "and on the other hand, we cannot assume the actuality of any such factor in the light of our present knowledge of heredity." In view of this very unsettled state of our knowledge the author has, for some years past, preferred the terms intrinsic and extrinsic, instead of hereditary and acquired. INTRINSIC FACTORS Several anomalies of dentition, and sundry constitutional peculiarities, causing malocclusion of the teeth, are due to certain inherent, systemic influences. We term these the 56 THE ETIOLOGY OF MALOCCLUSION intrinsic factors; some of them being congenital, and probably inherited, others not. Anomalies of Number. — These are found in both the tem- porary and permanent series, and frequently stand in causal relation to a malocclusion. Thus there may exist a deficiency Fig. 13 Congenital absence of the left upper temporary first molar, permitting the mesioversion of the second temporary and first permanent molars. in the number of teeth (Fig. 13) which permits the adjoining members to migrate into abnormal positions. When more than twenty teeth appear in the temporary dentition, or more than thirty-two in the permanent, we term it redun- dancy. This may lead to a crowded arrangement of them in tfeeir respective arches (Fig. 14). INTRINSIC FACTORS 57 According to Biisch/ there are three kinds of super- numerary teeth: (a) Those with conical crowns and root; (6) tubercles; and (c) supplemental teeth, or those of normal form (Hollander). Premature extraction of a temporary tooth, or other traumatic influence, might occasionally be Fig. 14 Shows the result of redundancy of number; note the supernumerary tooth between the upper centrals. responsible for a deficiency in the permanent set, but it is obvious that most anomalies of number are not due to extraneous causes. Atavism has long been regarded as a cause of redundancy; and more recently, their budding off from the common dental lamina has been suggested as a probable explanation of supernumerary teeth. But according 1 Deutsch. Monatsschr. f. Zahnheilk., 1886-87. 58 THE ETIOLOGY OF MALOCCLUSION to Tomes/ "our present knowledge of the subject will not enable us to recognize the cause which has produced" anomalies in the number of teeth, though syphilis, rickets, and other maladies have frequently been mentioned. IMcQuillen,^ Tomes,'^ and many other investigators have recorded numerous cases where anomalies of number were transmitted through several generations of the same family. Fig. 15 shows the model of the upper arch of a father and Fig. 16 that of his daughter, taken from the author's collec- tion. Frequent!}'' the histories of such cases are so vitiated by premature loss of teeth, i. e., by caries and extraction, that they are of little value. Yet it is undoubtedly true that, in most cases, they are congenital and therefore transmissible. Anomalies of Form. — Though rarely met with, anomalies of form occasionally enter into a malocclusion, and they suggest interesting morphological questions. They may express themselves in various ways, e. g., deficiency, redun- dancy, dichotomes, etc. When affecting the anterior teeth they usually present a disfigurement, and frequently cause malocclusion of the adjoining teeth. Fig. 17 shows the models of a boy, aged nine years, exhibiting a fusion of the upper centrals and laterals. Fig. 18 illustrates a case of redundancy of form in a right upper central incisor, being fully one-third longer than the left central. Irregularity of size may also be complete, affecting the entire tooth, or partial, being limited to the crown or root. Abnormal Frenum Labium. — Occasionally, cases present themselves with an abnormal space (diastema) between the central incisors.* In the upper arch it is usually due to > Dental Surgery, 5th ed. ^ Dental Cosmos. ilbid. < Angle, Dental Cosmos, 1899. INTRINSIC FACTORS 59 an excessive development of the frenum of the hp. The fibers of this muscular attachment are of sufficient density, Fig. 15 Shows model of a father with deficiency in size of the right upper lateral, and of number of the left lateral. Fig. 16 From the upper arch of his daughter, exhibiting the same anomalies, though on the opposite side of the mouth. 60 THE ETIOLOGY OF MALOCCLUSION and its movements so constant, that it prevents the teeth from coming into normal contact. Fig. 17 Anomaly of form due to the fusion of tooth germs. Fig. 18 ^^^^^^mm 1 m A K^fik, WaM til ;W!^ ¥jm """! B Fledundancy of form in a right upper central incisor. (After Lukens.) INTRINSIC FACTORS 61 This factor is usually classified as an acquired cause, or as a "local" cause, but the author is fully convinced that this is an error. Clinical experience uniformly tends to show that in all cases brought under early observation the same abnormal conditions exist during the period of the temporary dentition. Wiedersheim^ has shown that the raphe and gapilla palatina^ are more highly developed in the embryo and during early infancy than in later life. This papilla has been investigated by Merkel,^ who found it to be a sensory organ, and that it probably assists the palatine ridges in the trituration of food. Wiedersheim has also offered the suggestion that the raphe is "the remains of palatal teeth handed down even to man." In the absence of any authentic cases showing that an abnormal frenum is due to extraneous influences, we are constrained to regard it as an evidence of faulty develop- ment during embryonic life. Atavism suggests itself as a probable cause of such faulty development; but whatever the cause, it is plain that it is intrinsic. Fig. 19 shows the models of a case, aged eight years, in which the frenum of the upper lip was found to be the cause of the very wide space betw^een the upper centrals. Ketcham's extended investiga- tions with the x-rays conclusively demonstrate that such maldevelopments are in no wise related to an opening of the maxillary suture. Cleft Palate. — A congenital malformation of the palate usually so interferes with the development of the maxilla that if allowed to persist to the completion of the permanent dentition a malocclusion is an inevitable sequela. Fig. 20 shows the models of a girl, aged fourteen years, in which 1 The Structure of Man, p. 155. 2 Ibid, p. 146. 62 THE ETIOLOGY OF MALOCCLUSION Fig. 19 Abnormal frenum labium. Fig. 20 Upper arch of a case of malocclusion after an operation for cleft palate. INTRINSIC FACTORS 63 this deformity and the accompanying malocclusion are very evident. Fortunately, such cases are rare, though, as Bland Sutton^ long ago pointed out, they are transmissible. He says: "Cleft palate has been known to occur in offspring of affected members, and if it were possible to practise selective breeding in man as in dogs, a race of men with cleft palates and harelips could be produced." The treat- ment of the maxillary deformity usually falls to the oral surgeon, though subsequent orthodontic interference may occasionally be indicated. Dr. Dunn has reported the treatment of such a case to the American Society of Orthodontists (Denver, 1910). Anomalies of Position. — As already intimated, recent studies by orthodontists tend to emphasize the extraneous influences which are responsible for malocclusion. There remain a few forms of malposition, however, which cannot be attributed to them. I refer to transposition and those extreme forms of impaction for which Grevers- has suggested the term perversion. Fig. 21 shows the cast of a denture, sixteen years of age, in which the upper laterals, canines, and first bicuspids have exchanged places. Fig. 22 is from Dr. Cryer's collection, showing two impacted canines in the intermaxillary region. The causes of such anomalies are unknown, though obviously intrinsic. Asymmetry of the Jaws. — The jaws, or foundation structures upon which the teeth and their alveolar processes are placed, may, according to Talbot, be malformed in approximately 30 per cent, of apparently normal individuals. It is clear that if these structures are inharmoniously developed to 1 Evolution and Disease. 2 IV International Dental Congress, St. Louis, 1904. 64 THE ETIOLOGY OF MALOCCLUSION any considerable degree, the superimposed teeth are very apt, upon closure, to come into malocclusion. Both the Fig. 21 Transversion of the upper lateral incisors, canines, and first bicuspids. Fig. 22 Perversion of the upper canines. (After Cryer.) INTRINSIC FACTORS 65 upper and lower jaw may be thus affected, and while many arrests of development are traceable to abnormal occlusion, and therefore abnormal function (which speedily corrects itself after orthodontic treatment), there are rare instances which cannot be so easily disposed of. The causes of such developmental disturbances are not well understood. (See Chapter V.) Anomalies of the Tongue. — Congenital anomalies of the tongue, which have been described by Virchow, Holt, and others, exert their abnormal influences upon the dental arches, resulting in deformity. SchendeF and Angle^ have reported cases of this kind. When the tongue is excessively developed (macroglossie) it tends to enlargement of the dental arches, causes a spreading of the teeth, and conse- quent loss of contact with their neighbors. When arrested development exists (microglossie) the full normal influence of its muscular action is absent, which is usually followed by a crowded arch. (Compare Fig. 28.) Nutritional and Specific Infectious Diseases. — Diseases of nutrition, like rachitis, scorbutus, and marasmus, generally affect the process of dentition, though they are usually con- fined to the period of infancy. Congenital syphilis very often affects the permanent teeth, and, according to Hutchinson, "typical syphilitic teeth have notches in their incisal edges and are dwarfed both as regards their length and breadth." According to Keyes, Black, and others, such teeth are not invariably an evidence of this disease. It has also been claimed by Hill,^ Saleeby,^ and other English > Deutsch. Monatssch. f. Zahnheilk., 1903. 2 Malocclusion of the Teeth, 7th ed., 1907. ' Heredity and Selection in Sociology, London, 1907 * Parenthood and Race Culture, New York, 1909. 66 THE ETIOLOGY OF MALOCCLUSION writers that racial poisons, like alcohol and lead, are capable of producing malformations. And the late Herbert Spencer^ suggested the deleterious influence of vaccination as a prob- able cause of the alarming increase in teeth and eye affections among the inhabitants of Great Britain. EXTRINSIC FACTORS The factors embraced in this group are more readily recognized, probably because the operator comes in daily contact with them. A thorough knowledge of them is also imperative, since it enables one to successfully combat their action and thus obviate the development of many forms of malocclusion. Premature Loss of Temporary Teeth. — ^The necessity for the conservation of the temporary teeth during their allotted period is a truth that is gaining wide acceptance. The cumulative evidence of the disastrous results following their early loss through promiscuous extraction, or neglected progressive caries, is becoming a sufficient argument to all conscientious practitioners. Premature loss and pulp exposure due to neglected caries tend seriously to interfere with normal function; and in the development of the denture and its related structures normal function plays the leading role. Furthermore, the loss of a single tooth, or even of a part of a tooth, produces a break in the continuity of the arch and permits abnormal movements of the adjacent teeth. Premature Loss of Permanent Teeth. — The early loss of permanent teeth, especially of the first molars, is now 1 Facts and Comments. EXTRINSIC FACTORS 67 regarded as an established etiological factor of malocclusion. In action it is similar to the loss of temporarry teeth as described above, and is very frequently accompanied by a deepening of the "bite," or a destruction of the normal plane of occlusion. Prolonged Retention of Temporary Teeth. — The prolonged retention of temporary teeth, should they persist long after the need which occasioned them has ceased, r^nother prolific factor in the causation of malocclusion. An erupt- ing tooth is suspended, as it were, by its soft attachment tissues, and the slightest pressure, if it be constant, is sufficient to deflect it in its course. The orifice through which a tooth passes in its journey of eruption is greatly enlarged by the absorption of the crypt walls. Of course, we have our eruption tables, but many teeth deviate from the averages there set forth; and clinical observation teaches us that there is an opportune time for the exfoliation of each temporary tooth. The operator should, therefore, exercise judgment in every case of removal of temporary teeth. Fig. 23, a, shows the evil results of the premature loss of temporary molars, permitting the mesial eruption of the upper first molar. Subsequently, the first and second bicuspids were also forced into mesioversion, and thus encroached upon the space the cuspid should occupy, which came at a still later period. The left upper temporary lateral was retained too long, causing a linguoversion of its permanent successor (b) . On the right side (c) the elongated first molar is noted coming in contact with the lower gingival ridge, which is due to the early loss of the lower first perma- nent molar. Nasal Obstruction. — ^The importance of normal respira- tion and of a rational nasal hygiene, particularly during THE ETIOLOGY OF MALOCCLUSION Fig. 23 a, mesioversion of the upper permanent molar resulting from premature loss of temporary molars; 6, linguoversion of the upper lateral due to prolonged retention of its predecessor; c, beginning supraversion of an upper molar which has been deprived of occlusal contact. EXTRINSIC FACTORS 69 the developmental period, can hardly be overestimated. "Obstruction of the free passage of air through the nose is one of the most frequent and important consequences of nasal disease. The obstruction may be partial or complete, periodical or constant. When chronic nasal obstruction occurs at an early age, it exercises deleterious effects on the neighboring parts, on the general well-being, and on the development and growth of the whole body. The full consequences of nasal obstruction are most frequently seen in children suffering from adenoids." It may be due to one or more of the following anomalous conditions: (a) Adenoids, (6) deforviities of the septum, (c) hyper- trophies of the turbinates, and (d) nasal polypus. Another condition frecj[uently met with, and ver}' often associated with lymphoid hyperplasia of the nasopharynx, is hyper- trophy of the tonsils, constituting an hypertrophy which includes what has been called the "lymphoid ring," or "ring of Waldeyer." ~TKe'~more important direct effects of nasal obstruction Lack^ places as follows: Loss of nasal function, the open mouth and its mechanical consequences, deficient oxygenation of the blood, and deformity of the chest walls. The symptoms due to a constantly open mouth, and which especially appeal to the orthodontist, he enumerates thus: The typical fades, malformation of the jaws, malposition of the teeth, and collapse of the alee nasi. In Figs. 24 and 25 are shown the models and photographs of a girl, aged twelve years, which are typical of the conditions under discussion. In his very able investigation of this type of deformity Lack concludes as follows: " Diseases of the Nose, p. 56. 70 THE ETIOLOGY OF MALOCCLUSION Fig. 24 Malocclusion resulting from nasal obstruction. Fig. 25 '•r. Facial deformity accompanying case shown in Fig. 24. EXTRINSIC FACTORS 71 "Thus most observers agree that the deformities in question are frequently, if not invariably, associated with mouth breathing. Ziem's experiments demonstrate con- clusively that they may result from it. He obstructed the nostrils of puppies and other young animals, and found that great deformity of the bones of the face resulted in later life. There seems every reason to believe that nasal obstruc- tion precedes and causes the facial deformity. The latter is never congenital, but it follows after years of mouth breathing; the changes can be arrested, and will even retro- gress, if the cause be removed." Vertical and mesial malrelations of the lower dental arch, and malformation of the mandible, are frequently associated with mouth breathing. Case^ suggested the latter as a cause, and that hypertrophy of the tonsils frequently stands in causal relation to them. But the subject of nasal obstruction is a vast one, forming a large part of the field of rhinology, and it would carry us far beyond the confines of the present chapter to attempt a detailed treatment of it. For further study, the student is referred to text-books on diseases of the nose and throat. Habits. — Another rather fruitful cause of malocclusion are sundry habits of childhood. Foremost among these may be mentioned the habits of thumb and tongue sucking, and that of lip biting. The first is probably the most common, and very frequently hardest to discontinue. They are usually acquired during infancy, when the parents or nurse regard them as harmless, or even pleasing. But when we reflect on the mechanics of maxillary development, on the ease with which growing tissues are moulded into form, and 1 Dental Review, July, 1894. Fig. 26 ^^^ ,_^M^^^^^ ^^ ivA ^^gUjj^^/l//^^^ HKfrfS ^ 1 Thumb sucking. Fig. 27 Lip biting. EXTRINSIC FACTORS 73 on the constancy of these subtle influences, we readily appre- ciate their gravity and soiu'ce of harm when continued for a long period. Fig. 26 shows the influence of thumb sucking, causing the labioversion of the upper incisors and the lingual inclination of the lower. The constant biting and sucking Fig. 28 Tongue sucking. of the lower lip causes similar deformity, as shown in Fig. 27. Tongue sucking, though less common, permits the elonga- tion of the posterior teeth (allowing an abnormal elevation of their occlusal planes) and prevents the normal contact of the anterior teeth. Fig. 28 shows a case of this type. Some writers have classified mouth breathing as a habit, 74 THE ETIOLOGY OF MALOCCLUSION though it is obvious that it is but a symptom of pathological conditions of the respiratory tract. Herbst^ also mentions the probable influence of the following, which are frequently overlooked: The use of pacifiers during infancy, the sucking of cheeks, the biting of the upper lip in mesioclusion of the lower arch, resting the cheeks upon the hands, resting the chin upon the hand, and sleeping on one side. According to this author, Peckert has suggested the biting of cigar tips as practised by cigarmakers; Palltorf the biting of threads among seamstresses; the playing of musical instruments like the flute, etc., and the artificial deformities of the teeth as practised by many primitive races (Schroder), as causing deformities of secondary importance. Accidents and Traumatic Influences. — Falls, or violent blows upon the teeth, and fractures of the alveolar processes and maxillae, may cause malocclusion if their treatment is neglected; though Angle and other writers have conclusively shown that such deformity can readily be prevented if the proper treatment is provided. Tomes^ reports a case of malocclusion accompanied by malformation of the mandible, in a patient, aged twenty-one years, which was due to a burn about the neck and chest at the age of five. Fig. 29, taken from the author's collection, shows the casts of a youth, aged eighteen years, who was kicked in the mouth by a mule during his eighth year. Dr. Chilcott,^ of Bangor, Me., presents a paper in which he describes an "Obstetrical Deformity of the Mandible," which he attributes to a breech presentation. Jt is claimed that such presentations may cause a straightening of the ■ Zahnarztl. Orthopadie, p. 84. 2 Dental Surgery, 5th ed. p. 166. 3 Dental Cosmos, March, 1906. EXTRINSIC FACTORS 75 mandible, resulting in mesioclusion of the lower arch and malformation of the mandible. Fia. 29 Malocclusion due to an accident. Pericemental Affections. — It is well known that chronic infections of the pericementum and alveolar processes, commonly termed pyorrhea alveolaris, or alveolitis, may cause malposition of the teeth. Fig. 30 shows the cast of a denture, thirty-eight years old, in which the upper incisors were the seat of such infection, and which had gradually caused their labial movements during a period of two years. The distoclusion of the lower arch (which is evident) must not, however, be attributed to this cause, but to nasal 76 THE ETIOLOGY OF MALOCCLUSION obstruction in childhood, which the history of the case clearl}^ established. Fig. 30 BB jH^^^^^ ^^^^ ^\ ^^^^"''^K^ ^^^m rm lWl'*hr-TBrt« Hm m^^ r - -.^ ^H^^'y^ ■4 - K, '\ ^^^^^- '*«»"4>~.. ite^.**--'*'*^'"^ M V^'" -'^■^: ^^^.. lly^ - jcf"^ .J r ^ Malalignment due to alveolitis. Fig. 31 Hyperplastic formation of connective tissue preventing the eruption of a lower bicuspid. Neglected progressive caries of the deciduous teeth usuallj^ leads to pulp exposure and infection, and to chronic abscesses UNKNOWN FACTORS 77 discharging in a sinus. At the meeting of the Missouri State Dental Association for 1906, the author reported a case of a j^outh, aged sixteen years, who suffered from such neglect during his eighth year. The point of infection was in the left lower deciduous first molar, and caries soon destroyed all of the remaining tooth tissue that was not resorbed. The membranous surfaces of the adjacent tissue being inflamed, together with a cessation of suppuration, so coalesced as to result in a fibrous adhesion. This hyper- plastic formation of connective tissue caused the impaction of the first bicuspid, completely preventing its eruption (Fig. 31). Disuse and Artificial Nursing. — Disuse of the dental organs during childhood or the developmental period, and the artificial nursing of infants, are frequently mentioned as causes of arrested development of the maxillse and their processes. The modern methods of cooking food and neglected caries are also said to be largely responsible for the prevalent practice of improper mastication. In his study on The Mechanical Formation of the Denture, Korbitz^ has carefully analyzed such influences as active muscular pressure; the passive pressure of the soft parts; atmospheric pressure; pressure of the adhering tongue, as noted by Cryer; the functional influence of occlusion, etc., all of which are minimized, or even perverted, in cases where the above-mentioned factors are operative. UNKNOWN FACTORS The author has tried to enumerate all of the accepted factors of causation, yet he realizes that the facts here ' Oegt.-Ungar. Vierteljahrgch. f. Z^hnheilk., 1900. 78 THE ETIOLOGY OF MALOCCLUSION presented form but the merest outline of this subject. The problems of causation represent a field so vast that its boundary lines are hardly discernible. Many of the truths therein enclosed are reserved for future investigation. Some of the causes already mentioned, and others less generally accepted, might quite advantageously be grouped into a class and labeled as unknown. Some authors contend that civilization is a cause, that our modes of life in contrast with primitive man make for retrogression and degeneration. But there is little in the way of direct evidence regarding this, and it is probably only "one of those delightfully vague suggestions which are thoughtlessly advanced."^ Wallace very significantly adds: "Knowing, as we do, that 'thousands' of Chinese skulls have been examined, and only one trivial case of irregularity has been observed, and knowing also that the Chinese belong to the most ancient civilization extant, and, further, having been taught that irregularities are frequent among Hawaiians, we must be careful about laying too much credence on the idea that civilization is anything more than a frequent concomitant of irregularities." Race mixture has been suggested as a cause, especially in America, which has very aptly been called "The Melting Pot." It has been claimed that in mixed types, "the product of a cross between a broad- and a long-headed race, one contributes the head form, while the other the facial pro- portions." Anthropologists have frequently reported dis- harmonisms of this kind, but the data upon which similar deductions regarding the teeth are based are very scanty. In conclusion, it may be worth emphasizing the one great I Wallace, Irregularities of the Teeth, p. 98. UNKNOWN FACTORS 79 difficulty confronting investigations of this kind, viz., the lifetime of an observer is too brief to comprehend more than three generations; and even in cases where this is possible the data are frequently so vitiated that they are of little value. Our greatest hope for the future, therefore, must lie in the realm of experiments on the lower animals. CHAPTER V THE DIAGNOSIS OF MALOCCLUSION FIRST PRINCIPLES The dental axiom that only a normal denture can perform normal functions is gaining wide acceptance. This not only implies immunity to caries and the absence of sundry lesions of the oral tissues, but a denture whose architectonic form approaches the ideal. To perform the complex functions in response to which the teeth were brought into being, they develop characteristic forms and assume very appropriate anatomical positions. An intimate knowledge of these fine symmetrical relations is ver}^ essential in orthopedic practice, for in the correction of every malocclusion we are confronted with the two queries: (a) What is the nature and extent of the abnormality to be corrected? (6) What is the condition we wish to establish? Ultimately, these inquiries always lead us to ask the further questions: (c) What movements will be necessary? id) What method of treatment will best accomplish these movements? To the beginner the selection of the remedy, or the answer to question {d), seems most important; but it requires very little experience to show that this is an error, and that the only logical approach to the problems is in the order in which they are here presented. FIRST PRINCIPLES 81 The answer to the first query (a) imphes an accurate diagnosis, an interpretation of the abnormahty on a basis of normahty; and since the aim of every treatment is the estabhshment of normal relations, the significance of what constitutes a normal denture becomes evident. The arrangement of the teeth in the form of two parabolic curves within the alveolar processes of the jaws is called their alignment. When a tooth deviates in its position from this Fig. 32 Alignment and malalignment. ideal line, it is said to be in malalignment, or malposition (Fig. 32). When brought together in the act of mastication, normally arranged teeth are found to interdigitate very accurately. This intimate relationship existing between the cusps of the lower teeth in normal contact with those of the upper is termed occlusion. It is a primal function of the teeth, and is dependent upon their position. When a tooth occupies an abnormal position, and hence, on closure, comes into abnormal contact with its antagonists, it is said to be 6 82 THE DIAGNOSIS OF MALOCCLUSION in malocclusion (Fig. 33). The latter is a generic term used to collectively designate the various abnormal forms of occlusion. Occasionally, teeth assume such extreme mal- positions that they are actually in non-occlusion, failing in contact with their antagonists (Fig. 28). Malocclusion of the teeth presents itself in an almost end- less variety of forms, and for many years it was an accepted belief that their classification constituted a hopeless task. Fortunately, numerous investigators were not similarly Fig. 33 Occlusion and maloccluaion. minded, but endeavored to bring order into this apparent confusion, to detect similarity in so vast a number of devia- tions from normality. They realized that a comprehensive classification constituted the main problem in the difficult art of diagnosis, and hence devised systems for this purpose. The first recorded attempt was by the German dentist, Kneisel,^ who proposed the two groups, partial and complete. ' Der Schiefstand der Zahne, Berlin, 1836. DEFINITION 83 By the term 'partial, he ment malposition of the individual teeth; and by compkie, he had reference to the abnormal relations of the dental arches. From among the many other methods proposed since then, we may mention those by the following authors as the most important: Carabelli/ Magitot,^ Iszlai,^ Sternfled/ Angle/ Welcker/ Grevers,^ Herbst,^ Zsigmondy,^ and Villain.'" Most of these efforts at conceptual shorthand are more or less comprehensive, and are largely based upon patho- logical manifestations. Many others proposed from time to time were based upon the treatment to be instituted, and were, needless to state, fallacious. Furthermore, several of these schemes contained proposals for an improvement in our nomenclature, embracing systems of terms which, by their very etymology, would convey a picture of the conditions implied. But desirable as such efforts appear, they have not altogether removed our difficulties, and, at the present writing, not one of them has gained universal acceptance. DEFINITION Broadly interpreted, every diagnosis implies a considera- tion of several general conditions, e. g., the age, general and oral health of the individual, the relative degree of growth and development, the recognition of causative factors, etc. ' Handbuch der Zahnhl., Wien, 1844. 2 Traits des anomalies du systSme. 3 Internat. Med. Cong., London, 1S81. ^ Ueber Biszerten und Bisanamolien, Miinchen, 1888. ' Dental Cosmos, 1899. ^ Archiv f. Anthropologie, 1902. " IV Internat. Dental Cong., St. Louis, 1904. s Deutsch. Zahnarztl. Woch., 1904. ' Oestr. Zeit. f. Stomatologie, Wien, 1905. '» Zeit. f. Zahnarztl. Orthopadie, Berlin, 1910. 84 THE DIAGNOSIS OF MALOCCLUSION Custom, however, limits the use of the term to the art of differentiating one affection from a group of abnormahties having similar symptoms. Thus in orthodontic practice it embraces: (a) The distinguishing of one form of mal- occlusion from another; (b) the detection of anomalies of dentition (and of the jaws and related structures) other than those of position and occlusion; and (c) the degree of facial deformity associated therewith. GENERAL OUTLINE OF THE ANOMALIES OF DENTITION In 1877 the French dentist Magitot^ proposed a com- prehensive scheme for the many deviations from normality found in the denture of man. Though based upon the records of 2000 cases, it was formulated prior to the introduc- tion of many of our present methods of treatment, which latter have greatly extended the field of dental orthopedics. He therefore omitted mention of the deformities of the facial lines, and of the maxillary structures beyond the teeth, presenting a classification substantially as follows: (a) Anomalies of eruption; (b) anomalies of number; (c) anomalies of form and structure; and (d) anomalies of position. The anomalies of eruption may be further classified into premature and tardy; those of number, into deficiency and redundancy; those of form and structure, into partial and complete, etc. Orthodontic art occupies itself largely with the correction of what Magitot termed the anomalies of position, but it should not be forgotten that any of the other forms mentioned above (and anomalies of the jaws) may be found associated with them. 1 Traits des anomalies du systeme. THE DIFFERENTIATION OF THE VARIOUS FORMS 85 THE DIFFERENTIATION OF THE VARIOUS FORMS Let us first ask ourselves, What conditions usually enter into a malocclusion? The answer to this question must be stated as follows: There are just three conditions which may conjoin in a malocclusion — conditions so fundamental that most writers now recognize their basic significance — and each one of these conditions is reducible into element- ary divisions, regardless of their manifold combinations. Concisely expressed, these three conditions are: (1) Mal- formation of the jaws and their ijrocesses; (2) malrelation of the dental arches; and (3) malposition of the teeth. Let us briefly consider these three conditions in the order of their gravity. Malformation of the jaAvs is the most serious condition we have to deal with, and at times constitutes a deformity so severe that its correction lies outside of our domain. Therefore, when a case presents a pronounced malformation of one or both jaws, it should be emphasized and receive first mention in the naming of the deformity (Fig. 34) . If we could remove all of the soft, overlying tissues from the mandible in such a case, exposing it to full view, there can be no doubt that the general deformit}^ of this bone, and not the superimposed teeth and their occlusion, would attract our first attention (Fig. 35) . And as we ponder over it, how futile all orthodontic efforts at correction would seem, especially if they blindly ignored this foundation. Of course, the age of the patient is an important factor in the treatment of these cases; and recent developments in the methodology of our art have established the fact that early treatment of malocclusion (by securing normal dental function), Fig. 34 Mandibular macrognathism. Fia. 35 Shows the maloccltision of Fig. 34. The bilateral mesioclusion is but a symptom of the jaw deformity. THE DIFFERENTIATION OF THE VARIOUS FORMS 87 invariably corrects the menacing deformity beyond the teeth and their alveoli. It is obvious, moreover, that malformations of the jaws may express themselves in several ways, hence it is desirable to enumerate the various kinds and to adopt a satisfactory terminology. Now, medical literature has for years recog- nized the congenital deformities of the jaws under the group-term polygnatJiism, embracing epignathism, agnathism, hypognathism, etc. And continental European writers have used the ending gnathia (meaning jaw) quite liberally, so that it is not entirely new in dental science. The author, therefore, suggests its adoption in this connection. Deformities of the jaws may unfold themselves as over- developments, for which the term macro gnathism serves admirably; or they may express themselves in arrested development, in which case it is termed micrognathism. When confined to the upper jaw, it may be indicated by the word maxillary; or, if confined to the lower, it is termed mandibular. When both jaws are similarly affected, the term himaxillary is used. Furthermore, the author is of the opinion that these terms should only be used for those extreme deformities which are not amenable to orthodontic procedure. The arrangement of the teeth in the form of two arcades or graceful curves (an upper and lower, each with its right and left sides) demands a fine adjustment of the individual members of each if a symmetrical, well-balanced ensemble is to be established. Bearing in mind that we are here dealing with bilateral symmetry, we can readily see how all of the upper teeth, or all of the lower, could be in perfect alignment in their respective arches, and yet, on closure, fail to come into normal occlusion. In other words, either 88 THE DIAGNOSIS OF MALOCCLUSION arch (even though it retain a normal form) may be so displaced upon its osseous base that normal contact with antagonists becomes impossible. We term this condition arch malrelation (Fig. 36). It is obvious that this is invari- ably accompanied by malposition of the teeth, though the latter frequently exists without the former. Differently expressed, in cases of simple malposition, accompanied by normal relation of the arches, we have to deal only with anomalies of arch form. Since the publication of Kneisel's book many writers have recognized a few of the various forms of arch malrelation, but it remained for Angle to emphasize their far-reaching significance and to discover the unilateral and bilateral deviations. He also proposed diagnostic points, by means of which the mesial and distal variations may easily be detected. The mesiodistal relationship, or occlusion, of the first permanent molars is thus made to serve as an aid in the diagnosis of the mesial and distal forms. Of course, in mutilated cases allowance must be made for the possible abnormal position of these teeth. Angle's Classification. — Of all the schemes alluded to above, the Angle classification is the most widely accepted. It proposes a division of all forms of malocclusion into three classes as follows : Class I. Normal mesiodistal relation of the arches. Class II. Distal relation of the lower arch. Class III. Mesial relation of the lower arch. In its essence, therefore, it is a classification based upon the relations of the two dental arches (an exceedingly impor- tant distinction), though its numerical terminology does not indicate this. Now, in a consideration of arch relation we base our THE DIFFERENTIATION OF THE VARIOUS FORMS 89 differentiation upon normal closure, or occlusion, hence the ending elusion may readily serve us in our terminology for designating the various forms. To this ending we Fig. 36 B Normal and abnormal arch relation. A is diagrammatic of their normal relation, as indicated by the plane a, b, c, and d; in B their relation in a bilateral mesioclusion is set forth, the perpendicular b x indicating the normal. The line 6 y suggests their relation in distoclusion. prefix well-known anatomical terms, and thus get the fol- lowing: Mesioclusion, when the lower arch is mesial in its relation to the upper (Fig. 36) ; distoclusion, when it is 90 THE DIAGNOSIS OF MALOCCLUSION distal to normal (Fig. 37). As stated above^ both sides of an arch may be affected, when it is termed a bilateral Fig. 37 Bilateral distoclusion complicated by liuguoversion of the upper central inciso'^s. THE DIFFERENTIATION OF THE VARIOUS FORMS 91 inrshrlusion or disforhmnn. Or, if only one side is involved, we term it a iinihtfmil wcslocJn.von or (Usindimon (Fig. 38). Fig. 38 Unilateral distoclusion. 92 THE DIAGNOSIS OF MALOCCLUSION In a consideration of 1000 cases of malocclusion, Angle found 692 in which the mesiodistal relations of the arches were normal, the main difficulty being a malposition of the individual teeth, or an anomaly of arch form. In other words, one or more teeth were in malalignment, hence mal- occlusion, a condition recognized by all writers and loosely termed "irregularities." That there were several kinds of malposition was generally known, but again it remained for Angle to enumerate seven primary forms, and to call special attention to their possible combinations. Unhappily, this writer has become so enamored of the w^ord occlusion that he makes it serve in this instance by prefixing anatomical terms to it for the designation of these seven deviations. The author firmly believes that it would be a distinct advance if an ending denoting position were used instead, because the spoken word should be measurably descriptive. Again, having adopted the ending elusion as appropriate for the designation of malrelation of the arches, it becomes necessary to use another term to denote malposition of the individual teeth. Hence the author suggests that the widely used medical ending version (Lat. vertere, to turn, to change position) be used to denote malposition of individual teeth. This gives the following terms: Labioversion or huccoversion to denote labial or buccal malposition; linguoversion, when a tooth is lingual to normal; mesioversion, when mesial to normal; distoversion, when distal to normal; torsoversion, when rotated on its axis; swpr aversion, to denote elongation; infr aversion, for depression (Fig. 28) ; perversion, for impacted teeth (Fig. 22); and transversion, for transpositions (Fig. 21). Now, the mere fact that approximately 70 per cent, of all forms of malocclusion exhibit neither extreme malformation THE DIFFERENTIATION OF THE VARIOUS FORMS 93 of the jaws nor mesial or distal malrelation of the arches, emphasizes the advantage of a separate term for this large Fia. 39 Typical neutroclusion. 94 THE DIAGNOSIS OF MALOCCLUSION class (Class I, Angle). The author/ therefore, suggested that the word neutroclusion (Lat. neutro, in neither direction; Fig. 40 Neutroclusion complicated by extreme labioversion of the upper inciaors. ■ Dental Cosmos, April, 1911. THE DIFFERENTIATION OF THE VARIOUS FORMS 95 occlmio, to close) be used for the naming of this group (Fig. 39). Fig. 41 A, bilateral distoclusion complicated by extreme labioversion of the upper incisors; B, bilateral distoclusion complicated by infraversion of the upper incisors. 96 THE DIAGNOSIS OF MALOCCLUSION SUMMARY In confirming the diagnosis of a malocclusion we proceed by excluding all possible conditions in the order of their gravity. Thus dentofacial deformity, which is always serious, is first considered. Owing to the fact that it com- prises a large field and involves many grave points, it was deemed best to treat it separately (Chapter VI). Next in importance comes a consideration of malformation of the jaws; then the relation of the arches, or the totality of their alignment and occlusion; then the occlusion and alignment of each tooth, which necessarily implies the form of each arch; and such other anomalies as may be present. Finally, the naming of these deformities should be governed by the following rules : 1. Jaw deformities so extreme as to be beyond the scope of orthodontic treatment should receive first consideration. Their accompanying malocclusions are merely symptoms. 2. Arch malrelations amenable to orthodontic treatment are next in importance. 3. All cases of malocclusion accompanied by a neutral relation of the arches are spoken of as neutroclusions. 4. The individual peculiarities of any given case are best expressed by adding such qualifying phrases as "compli- cated by labioversion of the upper incisors," or " infraversion of the upper incisors," etc. (Figs. 40 and 41). CHAPTER VI FACIAL DEFORMITIES DUE TO MALOCCLUSION NORMAL VARIATIONS OF THE HEAD FORM As intimated in Chapter I, a frequent attribute of mal- occlusion is a marked inharmony of the facial lines. A rational basis for conclusive deductions regarding these deformities is a knowledge of the normal variations of facial form. To a large extent all faces are similarly formed, and their likenesses are patent to everyone; yet there exist in every face certain lineaments of character which stamp it with individuality. Indeed, in probably no other part of the human form is the variability of features so evident. The normal variations of organic beings have long been a subject for careful study; and since Darwin's day with renewed earnestness. It remained for Blumenbach,^ Cam- per,2 and Prichard^ to first draw attention to the relationship existing between the teeth and their osseous base and the profile or facial lines of man. This phase of scientific inquiry now forms an important division in anthropology, where, in common with other elaborate systems and classifications, it is termed anthropometry, the science of human measure- ments. The comparative study of the variable morpho- logical aspects of the skull comprises a subdivision termed craniometry. When the measurements are made upon the 1 Gottingen, 1775. 2 Berlin, 1792. = London, 1836. 7 98 FACIAL DEFORMITIES DUE TO MALOCCLUSION Fig. 42 Fia. 43 Fig. 44 Top view of skulls: Fig. 42, negro, index 70, dolichocephalic. Fig. 43, European, index 80, mesocephalic; Fig. 44, Samoyed, index 85, brachycephalic. (After Tyler.) NORMAL VARIATIONS OF THE HEAD FORM 99 living head it is termed cephalometry. Numerous methods for measuring the features have been devised, though very few have been sufficiently standardized to win universal acceptance. Much of the development of this branch of science Ave owe to the French anthropologist Broca. Cephalic Index. — In comparing a number of skulls even the beginner experiences little difficulty in detecting differ- ences of shape. " The form of the head is for all racial pur- poses best measured by what is technically known as the cephalic index. This is simply the breadth of the head above the ears expressed in percentage of its length from forehead to back. Assuming that this breadth is 100, the mdth is expressed as a fraction of it. As the head becomes pro- portionately broader — that is, more fully rounded, viewed from the top down — this cephalic index increases. When it rises above 80, the head is called br achy cephalic; when it falls below 75, the term dolichocephalic is applied to it. Indexes between 75 and 80 are characterized as 7neso- cephalic."^ Figs. 42, 43, and 44 are diagrammatic of these variations of form. Other Systems of Measurement. — Among the other systems proposed for the determination of differences of shape, mention may be made of Camper's method for the measure- ment of the facial angle (Figs. 45 and 46), Flower's gnathic index, and Turner's dental index.^ By means of the gnathic index, which is used to determine the amount of projection of the lewer part of the face, the races of mankind may be divided into three groups, as follows: Orthognathous, when below 98; mesognathous, when 98.1 to 103; prognathous. 1 Ripley, The Races of Europe, New York, 1899. 2 Tomes, Dental Anatomy, 5th ed., p. 517. Fia. 45 Fig. 46 Camper's measuremeDts of the facial angle. NORMAL VARIATIONS OF THE HEAD FORM 101 when above 103. With the dental index we determine "the relation of the size of the teeth to that of the skull," and get the three groups termed microdont, index 42; mesodont, index 43; and megadont, index 44 and above. Fig. 47 B Normal variation of the s\iinphysian angle. Fig. 48 Noiraal variation of the symphysian angle. Via. 49 Normal variation of the symphysian angle. Fig. 50 C 4m j ^^'•f Normal variations of alignment of the upper teeth. (After Broca.) Fia 51 F"ia. 52 Fig. 63 Showing variations in the relative position of the lower third molar. 104 FACIAL DEFORMITIES DUE TO MALOCCLUSION Still other differences of interest are the anthropological varieties of the palate, termed by Turner dolichuranic, mesuranic, and hrachyuranic; and the variations due to the development of the muscles of mastication. The latter are readily recognized in the changeable position of the Fig. 54 Fig. 55 Normal variation of the profile taken from life. Dental model of the case shown in Fig. 54. temporal ridge; the differences in width of the ascending rami of Europeans when compared with the aborigines; the varying degrees of parallelism of the borders of the rami; and the outward and inward everted angles of the lower jaw, which affect the width of the lower part of the face. Other and even more important facts of interest are the normal NORMAL VARIATIONS OF THE HEAD FORM 105 variations of the symphysian angle (Figs. 47, 48, and 49), and the ethnological deviations observed by Broca in the forms of the dental arches. Of the latter there are four varieties, which he designated parabolic, hyperbolic, ellip- tical, and U-shaped (Fig. 50). Fig. 56 Fig. 57 ^^1 tJ f . '-:jL^.'iiVa#:%^:.ifc