not been as good as I should have obtained from modeling compound, so I think that I shall take some of Dr. Drexler's time, and learn to take lower impressions. I believe I can take an upper impression as well as it can be done, but it takes from half an hour to an hour. Dr. Drexler. I never take less than an hour. Dr. Casto. I think I get a good one very often in half an hour. It may not be correct, but it is so much better than what I can do with plaster that I am pleased with it. I usually take from forty-five minutes to an hour in doing this work. Dr. W. J. Robinson. Modeling compound, to me, is not new by any means, because when I entered dental practice twenty years ago, it was in England. Modeling compound was used in England then, and plaster was comparatively unknown. In all these years I have been using modeling compound in the majority of cases, and have always had success with it, and for that reason have not been inclined to go entirely over to plaster. I have on numerous occasions seen Dr. Drexler do this work, and I have watched his results; they have been very successful. Anything that he says on this subject cannot but be of benefit to us. Dr. S. P. Cameron. I think that we owe Dr. Drexler a cordial vote of thanks for coming here and taking the time so unfortunately broken up. I did not think one could take a decent impression with modeling compound until I saw it demonstrated. While we have obtained a pretty good idea from what Dr. Drexler has said, I think, on account of the short time he had in which to prepare his paper, the Academy should extend to him. an invitation to come before us some other time with a patient and show us his work. He certainly understands taking impressions, does it thoroughly, and does it well. Dr. W. S. Hewitt. I do not think that the importance of taking impressions can be overestimated. We are losing a lot of teeth, and are finding that bridges we put on years ago have to be abandoned for some form of removable denture. For that reason, I think the subject of dental impressions is a very pertinent one at the present time. Dr. H. B. Matteossian. Clinical experience is the ultimate deciding factor in matters of practice, and I recognize from Dr. Drexler's paper that remarkable results can be obtained by the use of his method. There is, however, one question about partial impressions on which I should like to take issue with the essayist. In the first place, regarding the accuracy of the work. There is no doubt that when plaster and modeling composition are both used with the best technique indicated for each of these substances, plaster will give the sharper impression and more accurate detail. I think this is generally admitted. Now, in the case of an undercut space, where we take the impression in plaster, it is not necessary to build the denture to the full breadth of the space into the undercut. It has been my custom to wax it up with judgment, so that the trial plate will go in place without binding, making it possible for the finished piece to slip in and out with a minimum of trimming. Given these conditions, the plaster impression, taken in the usual way, is preferable, provided the wax is suitably carved before investing. This will give a much sharper impression of all the parts and a better fit than can be obtained with modeling compound. We have all seen remarkable results secured by the use of compound for full dentures, but when it comes to the partial plate, the use of plaster will give better results than if we attempt to do the work with modeling composition. By a person of dexterity, like Dr. Drexler, success will no doubt be obtained with composition in all instances, but for the general practitioner, besides the comparative saving of time, plaster will prove superior, if used in the sensible way of not waxing up to the full width of the undercut space. Dr. S. B. Luckie. I always admire a man who has faith in his technique. If he has confidence in that, he will make a success of it. Like Dr. Casto, I saw Dr. Greene, at the Jamestown Exposition, take an impression with modeling compound, but did not pay much attention to it. Those who use modeling compound claim they get an equal impression of the soft and the hard tissues, which they say cannot be done with plaster. Possibly, if someone could work out a technique with plaster, he could obtain the same results with it as those who use modeling compound. I have not yet perfected such a technique. When I have a plate to make now, I endeavor to take the impression with modeling compound, and get a pretty good impression of the roof of the mouth. Then I try to get a good impression under the cheeks and lips, but in doing this it is necessary for me to spend something like an hour and a half or two hours. However, with the little experience I have had with modeling compound, I feel that I can get better results with it than with plaster. But as I do not make more than three or four plates a year, my experience does not amount to much. Dr. Robinson. I use modeling compound exclusively in crown and bridge work where accuracy is absolutely necessary. A great many dentists make the mistake of not getting the compound cool enough before removing it, and that is why it draws. A number of men take a lower impression with a tray that has a handle on it, and when they take it out, they lift the tray up. The modeling compound is not hard, unless they have used ice-water, with the result that the compound draws and the impression does not fit in the back, when put in again. Dr. F. A. Fox. I must confess my inability to take partial impressions with modeling compound. I can take the full cases, but the partial cases give me trouble. A great many times, when I have leaning teeth and V-shaped spaces to overcome, I am prone to use plaster in order to overcome the very condition of which Dr. Drexler speaks: this can be done very nicely by paralleling the impression. If you get the impression intact you can parallel the depressions made by the teeth. In doing so and preparing the cast from the impression we will have the V-shaped spaces eliminated. In this way we get the same result as with modeling compound, and still have the accuracy of the plaster impression. I have obtained the best part of my prosthetic knowledge from Dr. Gritman, who has shown me the most beautiful results. So, in that, I like to follow his method. Dr. Drexler (closing the discussion). With reference to the question of Dr. Casto, I would say that the taking of a full lower impression with modeling compound is something entirely different from anything that he ever did with plaster. We do not use an impression tray to take a lower impression. The occlusal plane is what I take such an impression with. Supplee says he found out that it could be done with this from one of the dumbest men that he ever tried to teach. After attaching the compound to the bite plate and putting it in the mouth it is cooled and carved down to the arch and the length of the bite. Then we practically have a bite block. We take this occlusal plane, put an excess of modeling compound on the side next to the ridge, and ask the patient to close the lips. The tongue will prevent it from going back too far, and the lips will keep it from going too far forward. The patient is allowed to close down, and we let the compound cool. if we have one or touches the ridge. We It does not matter two spots where it We have the start, and we can build up from that. have the bite and lower impression at one time, and can then build the wings down on each side. The farther down we get the wings along the base of the tongue the less trouble we will have with the lower plate. A dentist sent a patient to me who was having trouble with a little plate on the lower ridge, in an effort to relieve the trouble the dentist had placed two suction chambers in the plate, one on each side. I took a piece of modeling compound, attached it to each side of the plate, and put it in the patient's mouth to get the wings. Then I told her to have the dentist put rubber where I had modeling compound. When this was done it was a very successful case. Dr. Matteossian says that he carves the wax. He is only doing what I do with the modeling compound. I carve the compound. Dr. Fox says to carve the cast, but how many men are capable of doing it? No man living can get it as it should be. Often you take a plaster impression and lose part of it, and build wax around to take the place of the lost plaster. Ninetynine times out of a hundred you do not get it right. Dr. Luckie says that he takes the impressions with modeling compound, and, if they do not fit right, he adds plaster and makes a new impression. That is what Dr. Greene calls the last aid to the injured. I hope some day to give you a demonstration of how you can get an accurate impression of the worst mouth with modeling compound. The society then adjourned. THE DENTAL COSMOS A MONTHLY RECORD OF DENTAL SCIENCE. Devoted to the Interests of the Profession. EDWARD C. KIRK, D.D.S., Sc.D., LL.D., Editor. L. PIERCE ANTHONY, D.D.S., Associate Editor. PUBLISHED BY THE S. S. WHITE DENTAL MFG. CO., PHILADELPHIA, PA. SUBSCRIPTION PRICE. including postage, $1.00 a year to all parts of the United States, Hawaiian Islands, the Philippines, Guam, Porto Rico, Virgin Islands, Cuba, and Mexico. Canada, $1.40. To other foreign countries, $1.75 a year. Original contributions, society reports, and other correspondence intended for publication should be addressed to the EDITOR, Lock Box 1615, Philadelphia, Pa. Subscriptions and communications relating to advertisements should be addressed to the BUSINESS MANAGER of the DENTAL COSMOS, Lock Box 1615, Philadelphia, Pa. PHILADELPHIA, MARCH 1918. EDITORIAL DEPARTMENT Dental Scientific Literature. OVER a quarter of a century ago we published in this magazine a series of articles by the late Prof. W. D. Miller under the general title "The Human Mouth as a Focus of Infection." The papers in question are the embodiment of his findings and conclusions reached after a long period of research dealing with the microbiology of the oral cavity. Among other things Miller's findings made clear beyond all doubt that an infected mouth is a constant menace to the health of the body; that the mouth is not only an incubator for the growth of a large variety and infinite number of bacterial organisms many of which are pathogens, and that the mouth is the principal portal through which disease-producing organisms find access to the body; but more particularly he furnished incontestable proof by laboratory experiment in vivo that certain mouth organisms were capable of setting up metastatic inflammatory foci in other parts of the body by transmission through the blood tracts a fact at present well recognized but at that time strongly disputed. Since the above-mentioned publication of the principles involved in that phase of Miller's researches his findings have been confirmed by the clinical observations of Dr. William Hunter, published in 1911, and further by a large body of subsequent observers, with the result that both in dentistry and in medicine, and to a large degree with the lay public, the doctrines thus set forth have become accepted as the expressions of biologic law. Moreover, as practical results flowing out of the publication of these discoveries, the whole complexion of dental practice and dental education has undergone fundamental changes that are little short of revolutionary. Formerly a distinct line of demarcation was assumed to exist between what we are wont to designate as operative dentistry and prosthetic dentistry respectively, and it was difficult if not impossible for the purely mechanical dentist to realize that the products of his handicraft involved even remotely any relation to the principles of physiology, pathology, or anatomy. Today these elementary biologic considerations are controlling factors in the adaptation of every dental prosthetic fixture, from a filling in a carious cavity to complete substitutions for the natural dentures. And a still further resultant of these pioneer researches of Miller is the universal recognition of the indispensability of oral hygiene as a means of prophylaxis against local and general disease originating in mouth infection. It is mainly the work of Miller that has in course of time reoriented the dental problem and diverted the attention of the dental profession in a proper degree from the business of repairing dental defects to the larger and more logical problem of preventing them. No student of dental history can fail to realize the epochmaking character of this pioneer work, yet it has required more than a quarter of a century for the fundamental truths of these researches to bear their legitimate fruit. Miller's early papers were regarded by the mass of the dental profession as the effusions of a scientific dreamer, impractical and without value or helpfulness to the dental practitioner in the solution of his problems. When the Independent Practitioner and the DENTAL COSMOS |