Department of Orthodontic Abstracts and Reviews

Edited by DR. EGON NEUSTADT AND DR. JOSEPH D. EBY, NEW YORK CITY

All communications concerning further information about abstracted material and the accept- ance of articles or books for consideration in this department should be addressed to Dr. Egon

Neustadt, 183 East Fifty-Eighth Street, New York City.

Applied Orthodontics. By Dr. James David McCoy, Philadelphia, 1935, Lea & Febiger.

In the fourth edition of his well-known and fundamental textbook on orthodontia, the author stresses the differentiation of diagnosis, etiology, and treatment. “Each should be considered separately and in proper sequence. Diagnosis comprises all methods essential to determine the nature and extent of anomalies. . . . Etiology seeks to determine the various causes for such aberrations. . . . Treatment strives to apply methods which will restore to natural form.“. . .

ORTHODONTIC DIAUNOSIS

The first of these three basic topics to be discussed is orthodontic diag- nosis. An introductory chapter deals with the growth of the masticatory apparatus, the normal relations of the teeth and dental arches, and the anatomical factors governing occlusion.

Then the dental and oral anomalies are described. They are divided into five pathologic conditions : (1) malposition of individual teeth; (2) malde- velopments of arch form; (3) malrelation of the dental arches; (4) malrela- tion of the dental arches accompanied with maldevelopment of portions of the maxilla or mandible; (5) miscellaneous deformities.

For studying these deviations, two methods of approach are enumerated ; one of them is the intraoral observation upon which Angle’s classification is based. This method, however, should only be used to supplant the second and more comprehensive method, which was introduced by Simon. It employs cephalo- metric principles and allows us to study not only the relation of the teeth to themselves, but also the relationship which the dental arches bear t0 certain

planes of face and skull. (For completeness sake, one of the graph surveying methods .should find a place in this chapter, perhaps the one developed by Dr. F. L. Stanton, this being at the present time the most accepted repre- sentative.)

Accurate denture and facial reproductions are considered essential for diagnostic considerations, and they are, for this reason, presented in great detail. The use of modeling compound is preferred as impression material because of its greater ease and simplicity. Its disadvantages can be overcome

986

Orthodontic Abstracts and Reviews

by the use of suitable trays, by the proper preparation of the impression material, and by the correct handling of it while taking the impression. After these factors are explained by means of suitable illustrations, the making of gnathostatic casts from the impressions is described, together with the finish

ing and trimming of them. Then follows the technic for plaster impressions, In addition to accurate dental reproductions it is advisable also to obtain

facial. reproduction, ‘(. . . a profile view showing t,he crucial relat,ions of the jaws being most essential.” Simon’s photostatic method is followed, which provides a. great degree of accuracy and allows subsequent photographs to be reproduced under identical conditions.

The roentgenogram is another important diagnostic aid. Its indications are manifold, and include: determining the presence or absence of unerupted teeth, guiding the extraction of deciduous teeth, observing teeth undergoing root movement, observing the development of third molars, etc.

Besides denture, facial, and roentgenographic records, it is-for the sake of a complete diagnosis-necessary to obtain a consultation record. This should contain all relevant facts in the clinical history of the paGent, such as the incidence of caries, number of teeth, size of tougue, general health, nose, lips, and facial muscles, and, in addition to this, all possible etiologic factors.

THE ETIOLOGY OF DENTAL AND ORAL ANOMALIES

Etiologic factors are divided into predisposing and determining causes. To the predisposing causes belong endocrine unbala.nce, metabolic disturb- ances, acute or chronic infectious diseases, prenatal abnormalities, congenital defects, and hereditary conditions.

Among the determining causes are the following: missing teeth, super numerary teeth, transposed teeth, malformed teeth, abnormal frenum labium, intrauterine pressure, sleeping and posture habits, abnormal muscular habits, malfunctioning muscles, premature shedding of deciduous teeth, tardy erup- tion of permanent teeth, prolonged retention of deciduous teeth, premature loss of deciduous teeth, loss of permanent teeth, and improper dental restorations.

The author devotes five chapters to a thorough discussion of each one of the factors mentioned. One of these chapters is entitled “Hereditary and congenital factors in dental and oral anomalies, ” and in it he relates the widely varying views on these subjects and suggests t,hat one should be ver? cautious before definitely attributing an anomaly to hereditary causes.

TREATMENT

Among a series of chapters entitled “Pre-Treatment Requisites” is one which deals with the tissue changes incident to the movement of tee&. It contains a description of the older theories on tooth movement (bending of the alveolar process, etc.) ; an anatomic and histologic consideration of the compact bone, the cancellous bone, and the alveolar process (which is essen-

988 Orthodontic Abstracts and Reviews

tial for the understanding of tissue changes) ; and the experimental evidence which Oppenheim has obtained in labial and lingual tooth movement, in tooth elongation, and in depression. In consequence, there is this warning: “In view of the fact that bone reacts so definitely to the stimuli of properly applied pressure, it is incumbent upon the orthodontist to consider carefully any contemplated movement, so that pressure, when applied, will bring about only those reactions which will be utilized for bone growth and development in the right direction.”

The orthodontic appliance is defined as “a mechanism for the application of pressure stimuli to malposed teeth, to bring about the necessary reactive processes within the bone which allow tooth movement in the direction de- sired and the growth and development in the arches essential to support the teeth in normal function.” Several matters should be considered carefully regardless of the type of appliance used: control of force, stability of attach- ment, strength and delivery, cleanliness, inconspicuousness, sources of an- chorage, force and resistance, and the selection of the anchor teeth. The construction of the principal elements of appliances (arch wires, anchor bands, attachment bands, and springs) is set forth by describing the proce- dures of various standardized methods.

Finally the operation of different types of appliances is discussed. Here we find labial arch wires with springs in conjunction with ligatures, auxiliary springs, open tubes (McCoy), and vertical pins and tubes. The lingual arch wire is presented in its plain form and in conjunction with auxiliary springs. (But a description of the edgewise arch is conspicuously absent.)

The author has selected a number of most typical dental anomalies and proceeds to demonstrate the suggested appliance design and adjustment for each of these types separately. Sometimes several alternative methods are suggested for the treatment of one type. In addition, nine complete case reports are presented, with their history and etiology, their diagnosis, and the therapy employed. Some unusual condit,ions are described which require unusual treatment, for instance, extractions. (However, if there are cases in which extractions of teeth other than the third molars are a necessary treatment procedure, the ones selected by the author are not convincing ex- amples of them.)

Post-treatment requisites form the last chapter of the book. They in- clude the problems of retention, muscle forming, normal metabolism, estab- lishment of a correct overbite, and the duration of post-treatment care.

This r&sum6 of the contents of the volume proves, without further corn- ment, its completeness and its ex’cellence as a textbook. The distinct differ- entiation of the material into diagnosis, etiology, and therapy is a most valu- able feature from the educational as well as the scientific viewpoint, since no branch of the healing art developed into a recognized science until this division had been adequately effected. It may be suggested that the arrange- ment of the chapters be modified to help carry out the differentiation. This

Orthodontic Abstracts cmd Reviews

will be accomplished by placing the chapters on ’ ‘Denture and Facial Repro- ductions ’ ’ and “Roentgen-Ray and Orthodontic Diagnosis ’ ’ with the 01 her diagnostic chapters at the beginning of the book.

The text is clearly written and fully illustrated; it is supplemented by a comprehensive table of contents and an index. Bibliographic references are ma.de whenever further elaboration on the subject would exceed the scope of this presentation. Students, dentists, and orthodontists who are unfamiliar with McCoy’s book will find it well worth their while to study this volume, and t,ltis is true even of those who have read one of the previous editions.

E. N.