Why cannot artificial teeth be made to resemble natural ones? The shape, size, color, and arrangement are under our control. To obtain the best results we must not use sectional blocks,—we must have single teeth. Let us see what is within the reach of every dentist who has talent enough to accomplish what he undertakes in artificial dentistry.

First, we have the porcelain composition, which can be made to imitate the natural teeth so nearly that they cannot be told at a very short distance. We have also compositions to imitate the gum near enough to avoid detection. With these we ought to be able to construct teeth that would very nearly resemble the natural ones. Single teeth are also made, very closely resembling the natural organs. In making molds for them the manufacturer selects the best-shaped natural teeth for patterns, and the color is very near like that of good, healthy natural ones. But natural teeth are not always regular in shape, nor are they always uniform in color in the same mouth, and by use they are worn on the cutting edges of the front and the grinding surfaces of the back teeth; so that in a person's mouth of over forty the teeth present a very different appearance from what they did at eighteen or twenty years of age.

As it is our object to represent the natural organs as near as possible, we should grind the teeth off as much as natural ones are worn. The practice is not to grind the teeth on the cutting or grinding surfaces. I say grind them all over if necessary; make them the shape you want; then if the ground surface is polished with pumice on a buff and finished with rotten-stone and oil, a better surface can be made than they possessed when they were burned. Ash & Sons polish their teeth and in doing so give a much more natural surface; so by grinding and polishing we can make single teeth any shape we wish.

In regard to the color, it is sometimes impossible, with all the varieties there are in the depots, to match the color of some natural teeth. By selecting such as have the color of the body of the natural tooth and using some mineral paint, a tooth can be made to match almost any natural one. Porcelain painting is now so common that the prepared colors can be purchased at any store where they keep artists' materials. Forty years ago they painted all porcelain teeth. When first burned they came out as white as beans and of nearly the same shape. They were then painted and burned again.

In setting an artificial tooth alongside a natural one that has been badly decayed and filled, and perhaps is black on the side opposite

the filling, the neck green and the edge blue,-it is impossible to match such a tooth unless we color one. If a tooth is selected of the color of the body of the natural one, ground and fitted to correspond in size and shape, and then painted to match, it may be made to imitate the natural tooth so closely as not to be detected. The painting may be done by any dentist who has skill and taste enough to make a good set of teeth. The mineral colors change very little in burning, unless they are heated much more than is necessary. The burning may be done in a muffle; one of the small furnaces used to make continuous-gum work is the best. If the dentist has not one of these he can use a clean crucible, heating the teeth to a full red heat in an ordinary fire; or they may be burned on a piece of charcoal with a blow-pipe, using a naked flame. All that is required is to heat to nearly the melting point of silver, when the silicious compound with which the paint is mixed fuses and forms an enamel. After selecting and preparing the teeth to suit the case, the next thing to be done is to arrange them. This requires more than ordinary talent to accomplish properly. Almost any mechanic with a few hours' instruction can put up a set of sectional blocks on a rubber base, and they will be as regular and beautiful as a row of piano-keys; but to make teeth irregular and give them a natural appearance to harmonize with the other features of the face requires the talent of an artist. The dentist should not be satisfied when he sees that the teeth are not too short nor too long, are the right color, not too large nor too small, or that they articulate properly. They may be right in all these essential points and yet have a very artificial appearance. He should take pattern after the portrait painter: commence with the patient present and notice not only the teeth, but all the expressions of the face, and arrange the teeth to harmonize with the features so as to give the best expression to them. A photographer sets his subject in a chair so as to get the best light, places the head in a fixed position and takes his picture. Everybody knows that a photograph gives no expression; it is only a picture of the person when he is in a quiet, passive condition. The portrait-painter will not only give you a picture, but will give expression to it; a little twinkle in the eye or a slight elevation of the lip is transferred to the canvas, so that you not only see the form but also the character of the person. As the artist is not always called upon to paint a beauty or persons of a similar cast of features, so with the dentist. If our patients were all alike in form and expression we might have sets made to suit them. It is not necessary for me to call your attention to the

deformity when the natural teeth are lost. The face is then shortened from one to two inches, the lips fall in and the chin comes up to meet the point of the nose, and every muscle of the face below the orbit is changed. Persons who have lost their teeth cannot smile or give a pleasant expression, their cheeks are wrinkled, they have no lateral motion to the under jaw, and in eating they can only roll the food into masses and swallow it without mastication. In fact they would be horrible to look at if we were not so accustomed to seeing them. A writer who is well informed estimates that there are twenty million teeth extracted in this country every year, and at least eight million of artificial ones made. When we consider the various expressions of feeling shown by the face, and the importance of the teeth in speaking and mastication, we may form some estimate of the necessity of replacing them when lost.

In using single teeth it is necessary to have some substitute for the gum. We have two such that answer the purpose well-the continuous-gum body and celluloid. Continuous-gum work has been before the profession so long and its merits have been so highly extolled that I shall give it not more than mention. It certainly makes the most perfect work when it can be used; but there are objections to it-it is heavy, liable to break, and not easily repaired. It has been in use more than thirty years, during which time it has been tried by many who have discarded it, and its use does not appear to be increasing.

Celluloid, when properly made, answers the purpose well. It is cheap, more easily managed, lighter, can be easily repaired, and may be made to imitate the natural gum very closely. It is not necessary to give the chemical composition of this compound. It is known to be made from gun-cotton by adding camphor and some oxide of zine; a little vermilion is also added to give it color. It softens to a doughy consistence at a temperature of 300° F., when it may be pressed in molds to any shape.

The first step in arranging the teeth is to obtain a base-plate. Wax is used, but it is too soft in the mouth. Wax and paraffine in equal parts, colored with alkanet root make a good plate; gutta-percha and modelling compound are also used, but the best and most satisfactory is a metallic base-plate. It is not much trouble to make, and it will retain its shape and will show if the impression of the mouth is correct. Here we should stop until the plate is a satisfactory adaptation. When this is acccomplished we may arrange the teeth on it by means of paraffine and wax. If the operator will take the

trouble he can make the case just as it is wanted when finished. The wax is covered with tin foil, worked into place with a burnisher. Rugæ may be made in the wax on the palatine part so as to give a more natural feel to the tongue. The tin foil may be stippled to give a granular appearance. By having the wax covered with foil on both the outside and the palatine surface and making the case on a metal cast, it will require very little finishing after it is pressed.

Single teeth mounted on a gold plate, using celluloid to attach them and to form the gum, makes one of the most satisfactory cases for both the operator and the patient.

In working celluloid many fail from not having a suitable apparatus and from not taking sufficient care. It will soften at 212° F., and it may be pressed into shape at that temperature by using sufficient force. I have known it to be worked with boiling water in an open vessel, but it is only forced into shape and then has a tendency to spring; such cases get out of shape very soon. I have some specimens to show the effects of different temperatures on it. It should be heated to a temperature of 300° F. At this point it is in a doughy condition and may be molded into any form, with the certainty of its retaining its shape when cold, and with no liability to spring.

SECTION 1.-Continued.

The Ill Results Produced by the Use of Artificial Dentures upon Plastic Bases.

IT

PAPER BY WILLIAM H. DORRANCE, OF THE SECTION.

T is a sad and incontrovertible fact, that that disease which comes frequently under the notice of the dentist, known as dental caries, is universally prevalent, and is thought by careful observers to be on the increase. The loss of teeth resulting from other causes, particularly calculus in its various forms, is also appalling.

Though much painstaking effort on the part of members of the profession has been directed to the diffusing of practical informa tion relative to the proper care of the teeth and the pressing need of their salvation, much more has been said and done that is not only fallacious and harmful, but, in view of the high importance

of each member of the oral apparatus to the human economy, absolutely (though perhaps ignorantly) criminal. That the public at large, even highly intelligent and cultivated portions of it, are apathetically lacking in appreciative knowledge of the important functions of the teeth, and consequently indifferent to their loss or efficient restoration, is not surprising, when it is taken into consideration that the great majority of those who, by reason of their claim of membership in the dental profession, should know, are yet to become properly educated in the matter.

While the representative portion of the profession has been steadily advancing in the treatment of diseased conditions and in a knowledge of therapeutics, and may be said to be making headway in oral surgery; while it is becoming-nay, has become—justly noted for superior excellence in all operations upon the natural teeth, it has not made corresponding advancement, but has rather retrograded in the equally important department of dental prosthetics.

The reputation of a person is determined by his acts, and that of a profession is established by the abilities and activities of its members. In the rapid stride of those who are (by the process of "natural selection") placing themselves in the front as operative specialists, and of those whose love for the work has led them to devote themselves to the investigation of proximate causes, there has been, it is to be greatly regretted, a noticeable lack of any thought or care for prosthetic dentistry, with a consequent debasement of it, and desire of divorcement from it. On the other hand, the short-sighted and time-serving indifference with which assistants have been chosen, or so-called students admitted to the offices of reputable practitioners, and without subsequent preparation or direction of value and with scarcely a glance at a text-book during the few short months of their stay, have been carelessly allowed to launch out as members of the - profession (and come to be recognized as such by the too indifferent and pre-occupied public), has been the means of bringing to the ranks of the profession the men who, as numbers go, constitute the bulk of it, and into whose hands prosthetic dentistry has been largely allowed to fall. These, in the exigencies of the matter, have no thought or care for the advancement of the profession, or the amelioration of the condition of suffering humanity, save as it is to the present interest of their pockets. And hence we have a profession that, whatever its claims to advanced standing, has in its representative membership been gradually losing sight of, or, perhaps, has rather lost interest in observing and investigating not only the me