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Dr. Abbott then read his paper, entitled "Studies of the Pathology of Enamel of Human Teeth, with Special Eeferenee to the Etiology of Caries." *
Dr. C. N. Peiree, Philadelphia, wished to congratulate the association on the opportunity it had just enjoyed of listening to the results of the joint investigations of Professors Heitzmann and Abbott. The drawings which have been exhibited show many points about the hard structures of the teeth which are not easily brought before an association. The first diagram illustrates a condition that must have been confirmed in the embryo. The line showing the projection of the dentine up into the enamel must have assumed its shape before the fifteenth or sixteenth week of intra-uterine life, because calcification begins about that time. The dentine must have assumed its peculiar convoluted appearance before it was made permanent by the deposition of lime-salts. We have here an illustration of how a change, of structure is effected by the delegation of nutrition to some other locality. The point which shows above the dentine in the enamel was caused by a peculiar condition of the nutritive currents. We should always bear in mind, in considering these hard structures of the teeth, how readily they are changed when in their formative stage, early in life. The lines or rings on the section of a tree, which used to be thought to indicate the age of the tree, represent periods of growth. Sometimes two or three of these occur in a year, though usually there is only one. When more than one period occurs in a year it is owing to better nutrition and more favorable influence during that year. The enamel-layers of the tooth are like the rings in the tree. They show periods of growth. The soft tissues do not much exceed the hard in their rate of growth. That is, the soft tissues are not all formed before the hard; and during the period of formation some systemic condition may interfere to cause loss of continuity.
Dr. W. H. Atkinson, New York, was delighted with these specimens of proofs of the idealisms of tooth-structures. We may make a very good case out of an anomalous one, if we take it to be the regular order. If he understood the matter, we will find that it is not always the office of the enamel-pulp to be finally elaborated into the prisms or rods of the enamel and their interspaces; and this leads us to inquire into the the signification of all teeth having an enamel-cap. What becomes of the enamel-cap which presided over the formation in the embryonal condition is not settled. Sometimes it is worn off. It is always formed within Nasmyth's membrane when there is no interference with the currents of growth.
*This paper will be found at page 641, current number Dental Cosmos.
The very fact that the enamel has nutrition settles the question as to whether it is a vegetable or a mineral or an animal structure. The condition shown in the specimen No. 1 comes about simply by a rift in the lower border of the enamel-cap, allowing the ameloblasts to persist beyond their normal life; so that it can hardly be called abnormal. Invariably this is attributed to a want of lime, which he denied. There is as much lime there, pro rata, as anywhere else in well-formed teeth. The difficulty is a lack of consolidation. What that is cannot be determined until we have made many more observations. He hailed the ambition of anyone to work at this subject, and he did not care why the work was undertaken. We owe a debt of gratitude to Dr. Bodecker for his demonstration of the living matter in the hard structures of the tooth. But it does not matter how these breaks in continuity come about. When we speak of the etiology of decay, we must go behind all manifestation of decay, and if we say the cause is a microbe, we must know whether the microbe is necessary. He would ask, what is sterilized earth? It has been said that we must have the mineral before the vegetable, the vegetable before the animal. Those who speak thus have forgotten that the first differentiation of matter is the protista, which may be a mineral or not, according to its environment. We must get out of the old "organic" and "inorganic" ruts; we must have something which will blend them. Water is said to be a mineral. It is organic. There is really no inorganic matter except simple atoms.
Br. A. H. Thompson, Topeka, Kansas, wished to ask concerning the structure of the chalky spots shown in the illustration. Is the difference due to deficiency of lime-salts, or a deficiency of organic mineral elements?
Br. Abbott. The only evidence that there is a diminution of limesalts is the greater proportion of organic material, seen in the specimen under the microscope. It shows two or three times the amount found in normal enamel. The lime-salts are not so well organized as in sound structure, being loose, comparatively. With regard to the statement about sterilized earth, that was a quotation from the French, which he had given as he found it.
Br. T. W. Brophy, Chicago. Br. Abbott states that defects which are found in enamel when the teeth are erupted are always congenital.
Br. Abbott could not see how it could be otherwise.
Br. Brophy. According to Br. Eames (and his view is indorsed by Br. Black), these defects in the enamel can be caused by absorption, and by the same agent which brings about absorption of the deciduous teeth. The speaker had seen cases in which he was satVol. xxvu.—44.
isfied there had been considerable destruction of the enamel of the permanent teeth through retaining the temporary teeth too long.
Dr. Abbott. It is almost impossible that the condition referred to should occur after eruption, except that it might be possible, where one of the strata runs out of the surface, and is of a porous nature, for something to enter the enamel at that point and affect it along that line for some distance; and the process might be of such a nature as to justify the thought that absorption caused it. For himself, he hardly thought it occurred so; he had never seen nor heard of such a case.
Dr. H. H. Keith, St. Louis, had a peculiar incident of practice which seemed to support the view presented by Prof. Abbott. He had fitted a regulating plate in the mouth of a little girl, the plate covering one of the deciduous teeth. The patient was absent some two or three weeks. When the plate was removed, upon her return, he found the crown of the deciduous tooth spoken of in the plate. All the dentine was gone, but the enamel was all there.
Dr. Atkinson stated that he had given Dr. Abbott a section made twenty-seven years ago, which showed this very thing,—the enamel taken up by the same process which absorbs the dentine. Now, it must be reduced to a fluid before it is unbuilt. He has two sections yet uncut which have bay-like excavations in the enamel. Dr. Abbott, a long time ago, gave him a superior bicuspid which had lost two-thirds of its roots by absorption, and it was also perforated, to all appearances, by two beautiful drill-holes. How the absorption went across the tooth he did not know.
Dr. Abbott. The specimen which Dr. Atkinson spoke of was a temporary tooth. It was not one of this kind of cases, and its condition has no bearing on the subject under discussion. It was a case of absorption, while these show imperfect development of the enamel. He felt quite indignant that Dr. Atkinson had not ground the specimen which he gave him twenty years ago.
Dr. L. C. Ingersoll read a paper entitled "The Alveolo-Dental Membrane: Unity or Duality—Which?" *
During the morning session of the third day the resignation of Dr. George A. Mills as a member of the association was received and accepted.
The subject of Operative Dentistry was again taken up and the discussion concluded. The report of this discussion will be found in the October and November issues of the Dental Cosmos.
*This paper will be found at page 653, current number Dental Cosmos.
Dr. Peirce, from the committee appointed to consider the suggestions contained in the president's address, reported a resolution appropriating $100 to each of the Sections Y, YI, and YII, to be expended by them in the prosecution of their work.
On motion of Dr. H. A. Smith, the amount was made $200 to each, and the resolution as amended was adopted.
(To be Continued.)
HBST DISTBIOT DENTAL SOCIETY, STATE OP NEW YOEK,
The officers of this society desire to make the present year one of unusual interest to its members, and to the dental profession generally, which is hereby cordially invited to attend its meetings. It has been arranged to give clinics of a novel nature, and papers that will be practical, instructive, and entertaining.
In addition to the regular meetings, a number of special meetings will^be held, at dates to be fixed later, when clinics and papers will be given by the following-named gentlemen:
Clinic and paper by Dr. Wm. Herbst, Bremen, Germany, inventor of the Herbst method of filling teeth.
Paper by M. Whilldin Foster, M.D., D.D.S., professor of dental mechanism and metallurgy in the Baltimore College of Dental Surgery, on "Abnormal Conditions of the Antrum and Eestorative Treatment."
Clinic and paper by Dr. H. C. Eegister, Philadelphia.
Clinic and paper by Dr. E. Parmly Brown, Flushing, L. I., on "New Porcelain Bridge and Crown Work."
A lecture on "Facial Expression," by a very eminent sculptor of New York City, illustrated by clay modeling, pre-historic skulls, etc.
Tuesday evening, November 3, 1885. J. N. Farrar, M.D., D.D.S., on "Mechanical Appliances for Correcting Irregularities of the Teeth," with blackboard illustrations.
Tuesday evening, December 1,1885. Edwin T. Darby, M.D., D.D.8., professor of operative dentistry and dental histology in the University of Pennsylvania, on u Erosion of the Teeth: Its Cause and Treatment."
Tuesday evening, January 5, 1886. S. H. Guilford, A.M., D.D.S., professor of operative and prosthetic dentistry in the Philadelphia Dental College and Hospital of Oral Surgery, on "The Band Matrix and its Uses."
Tuesday evening, February 2, 1886. Frank Abbott, M.D., professor of operative dentistry and dental therapeutics in the New York College of Dentistry, on "The Treatment of Pulpless Teeth."
Tuesday evening, March 2, 1886. John J. B. Patrick, D.D.S., Belleville, 111., on « Progressive and Ketrogressive Physiological Metamorphosis of the Jaws and
W. W. Walker, Chairman of Executive Committee.
IEBEASKA STATE DEHTAL SOCIETY.
The ninth annual meeting of the Nebraska State Dental Societywas held at Lincoln, May 13 and 14/1885.
There was a large attendance, and eleven names were added to the list of membership. The following officers were duly elected for the ensuing year:
J. J. Willey, president; A. P. Johnson, vice-president; L. S. Moorer corresponding secretary, Fairmount; C. E. Tefft, secretary and treasurer; I. W. Funck, A. W. JSTason, and O. P. Baker, executive committee; J. W. Chadduck, W. H. Stryker, and J. K. Hopper, committee on membership; C. E. Tefft, F. L. Browne, and T. I. Hatfield, committee on publication.
The next meeting will be held at Beatrice, May 18, 19, and 2% 1886.
MINNESOTA STATE BOARD OF DENTAL EXAMINEES. The Minnesota State Board of Dental Examiners will meet on Tuesday, the 1st day of December, 1885, at the Eyan Hotel, in St. Paul, for the purpose of examining candidates for admission to practice in the State, and to indorse diplomas.
J. H. Martindale, Secretary, Minneapolis, Minn,
Dental Bibliography: A Standard Eeference List of Books on Dentistry published throughout the world from 153S to 1885. Arranged chronologically, and supplemented with a complete Cross-Beferenee to Authors. Compiled by C. Geo. Crowley. 180 pages. Philadelphia|: The S. S. White Dental Manufacturing Co., 1885. Price, cloth, $2.00.
We have in this volume the outcome of a long and laborious effort to present a complete list of distinctive works on dental subjects which have been published throughout the world from the earliest times. It catalogues 2047 titles, printed in the various languages in which the books appeared, and chronologically arranged. The work is divided into five departments or sections. Section I contains books published in Germany, Austria, Holland, Eorwayr Sweden, Denmark, and Switzerland (German); Section II books published in France, Belgium, and Switzerland (French); Section III books published in Spain and Italy; Section IY books published in Great Britain $hd Ireland; Section Y books published in America. An author's index appended in alphabetical order give& cross-reference to all the volumes catalogued.