President Cooke:—Dr. Gillett will show a warm-air apparatus.
Dr. Gillett:—I was prompted by the note on the card, saying that an apparatus for obtunding dentine would be shown, to bring up this apparatus, which some of you have seen before, as Dr. Brackett exhibited it at the last meeting of the American Academy of Dental Science. This is an apparatus for obtunding sensitive dentine, of which there are but a few of its kind in the country, and this particular one was sent to Dr. Brackett by Dr. Bogue, of New York. I have used it some for the last two or three weeks, and find that it is possible to produce very good results without hurting the patient. Those who have used Dr. Waite's obtundent, and have gotten satisfactory results with it, will perhaps appreciate my explanation in this way. I have used that with considerable success, and like it very well, and I find that I can do the same work with this apparatus, with the additional gain that its application is not painful, as a rule. It is simply a means of obtaining dryness in the cavity by the use of a continuous current of warm air.
H. L. Upham, D.M.D.,
Editor Harvard Odontological Society.
PHOSPHATE OF ZINC CEMENT AS ANCHORAGE
FOR PERMANENT FILLINGS.[2]
BY C. J. PETERS, D.D.S., SYRACUSE, N. Y.
About six years ago I read a paper before the Syracuse Dental Society on the subject, "Oxy. Phosphate," in which my main object was to bring forward the idea of its use as anchorage for amalgam fillings in particular. After the experience I have had with the method, I have nothing to retract, but can reiterate with emphasis every word said then. This, now, is no new untried thing I bring before you. For the last two years it has been talked of more or less throughout the country. I conceived the idea early in 1884 when a lady came to me for treatment in whose mouth were four teeth which two years previously she had been told were beyond saving, but had neglected having them extracted on account of the dread of the operation. I treated three of these teeth and filled the roots, but could think of nothing that would be retained in the crown but cement. I wondered if amalgam would stick to cement as the cement does to tooth structure. I tried it, and was successful, and those three fillings are in to-day and can be produced at any time.
The good results attending its use with amalgam, suggested at once numerous uses to which it might be put, as: anchorage for gold, foundation for any other filling at one operation, lining for thin walls when objectionable color of filling material could show through, cementing fillings which had fallen out or loosened intact, last to place temporarily or otherwise. As an anchorage, its greatest is, I believe, under amalgam fillings in cases of badly broken down molar and bicuspid crowns where, on account of excessive decay and nearness of the pulp, reliable undercut cannot be obtained, and if it could be, would so weaken what remained of the crown as to deprive it of strength to carry the filling. It is especially useful in molars where the buccal surface and a half or more of the grinding surface is gone, in bicuspids whose proximate surfaces are gone with a large share of the grinding, so that the opening of the cavity is the full size of the circumference of the tooth and the remaining walls thin. It is astonishing how many of these latter cases can be shaped and contoured with amalgam without a particle of the amalgam being in sight after the work is finished. If in an anterior proximal filling proper contouring make it necessary for some of the amalgam to show, the anchorage may be thoroughly relied on to permit of cutting out a small portion and facing with gold. The shading of the thin walls by the amalgam is absolutely prevented by the cement. I have in my own mouth a molar in which the filling was loosened by mastication five times on account of the cavity being one of the kind where reliable anchorage could not be obtained. The pulp finally became exposed from frequent cutting away of tooth structure, and the sixth filling was anchored by taking advantage of the pulp chamber, or a portion of it. To use cement as anchorage for amalgam, this is the process: Mix the amalgam according to your custom; place on a slab for mixing cement a small quantity of the liquid and powder ready to mix; then, the cavity being prepared, dry it thoroughly and keep it so while mixing the cement. This being done, place a small amount in the cavity, and at once upon it place a piece of amalgam, which should be so manipulated with the instrument suited to the size and shape of cavity as to force the cement under the amalgam all over the floor of the cavity. Care should be taken to not force the cement entirely to the cervical edge in proximal cavities, and any excess of cement used should be worked out at a point easy of access. By this time the cement is hard enough to be easily chipped off whenever it has been forced beyond the inner edge of the enamel. The filling with amalgam is proceeded with and finished in the usual manner. It is essential that the cement should not be smeared over the edges of the cavity, but carefully worked all over the dentine, closing the mouths of the tubuli, allowing the enamel edge free for contact with the amalgam. The edges of such a filling are better, and remain better than those of the ordinary filling, for the reason, I believe, that the cement controls, or at any rate lessens, the spheroidal tendency in the amalgam. In very deep cavities it is well to work into the cement a piece of hardened amalgam before inserting the fresh, as it lessens the amount of cement necessary, and also of the amalgam, and again prevents the tendency to spheroid. Proximal cavities in children's teeth are very easily filled with amalgam by this method, and without causing pain in cutting tooth structure.