At the period when transplantation was systematically performed, the operators kept themselves supplied with an assortment of dried teeth, i.e., sound teeth, obtained generally from the dead subject, to make use of in case the tooth to be transplanted should not prove adaptable to its new abode. The process is not spoken favourably of, as the results were mostly unsatisfactory, but at times such teeth became perfectly firm, and even resisted the greatest efforts at their removal. We can hardly for one moment suppose that teeth in the condition these were could have ever become attached to a living alveolo-dental membrane, and the difficulty of accounting for this firmness would have been great indeed, had it not been already solved for us. In Langenbeck’s Archiv. fÜr Chirurgie, vol. iv., is a paper on “The Replantation and Transplantation of Teeth,” by Dr. A. Mitscherlich, which deserves to be better known, and which, apparently, cannot have come under the observation of those who recently contributed to the Lancet on the subject, the excuse for which is less, since it has been translated into English.^[2] The author, in addition to much interesting and original matter, records the following experiment. In the upper jaw of a dog of a year old, Dr. Mitscherlich inserted into the socket of an incisor he had removed, a similar tooth taken from a dog’s skull, and which he retained in situ by means of a silver wire passed through a hole in the tooth, and a hole bored through the alveolar process of the jaw. “After six weeks the dog was killed, having been given during the last few days three grains of picronitrate of potash three times a day; the carotids were immediately injected. The muscles, like the gums, were coloured yellow: neither, however, in the implanted tooth nor in the sound ones was any alteration of colour perceptible. The silver wire was porous, and no longer held the tooth; it was removed. The tooth was quite firmly seated, and could not be moved in the least by the fingers. The gums, as in the remaining teeth, were accurately applied both to the alveolar process and also to the tooth itself, and nowhere could any alteration be found in it. The tooth was sawn through lengthways, together with the upper jaw, with a fine saw, so that the pulp cavity was laid bare in its whole extent. The latter was only filled with a little detritus, and no trace of the pulp was discoverable; none of the injection, too, had been forced into the cavity. The tooth was everywhere most intimately connected with the surrounding parts, and suppuration showed itself nowhere. Of the periosteum, on the other hand, there were only in a few places some small remains discoverable. On the posterior surface of the tooth two small cavities were visible; the larger of which lay more towards the point of the fang, and extended to the pulp cavity; they were filled with a soft substance, and their walls appeared roundish. These appearances were entirely confirmed by microscopical examination, inasmuch as only in a few places, especially on the anterior surface of the tooth, were traces of the periosteum to be demonstrated; where this was absent the tooth was eaten away, and its absorption had proceeded in such a manner, that a multitude of globular elements appeared on the section, resembling the fragments which we find in ivory pegs which have been bored into bones, and retained in them a considerable time; in the two above-mentioned cavities the absorption had proceeded farther and farther, and had at last attained its above-mentioned great extent. The cementum could still be demonstrated in certain places, it was, however, absorbed in the greatest part of its extent. In the cavities of the tooth substance, masses of bone were embedded, they were applied to the walls of the cavities without any kind of intermediate substance, and so held the tooth with such extraordinary firmness. This osseous deposit, which was directly connected with the alveolar processes, was freely traversed with blood vessels, which sometimes extended themselves close up to the tooth substance. It was also so fully developed, that the process had to be looked upon as fully accomplished, and therefore, a later exfoliation of the tooth was not to be expected. The dentine itself showed nothing abnormal.”

We have quoted the author of the foregoing at some length, as some of his conclusions upon this interesting experiment might seem antagonistic to our own. Thus, whilst we agree with him in concluding that a dead tooth becomes united to a living jaw by a certain amount of absorption of its fangs by osteoblasts, and a subsequent calcification of such tissue, we do not believe such process as fully accomplished or permanent. The valuable researches of Tomes and De Morgan show that during life a continual process of formation and absorption is taking place in bone, whilst the former has also pointed out that the process of absorption in the fangs of temporary teeth is one alternating between absorption and deposition, though in the end in favour of the former, i.e., that the osteoblasts which effect the absorption of the dentine often become calcified, but are again eventually decalcified and become active osteoclasts. What determines these bodies to act, so to speak, in a positive or a negative capacity would be most interesting to discover, and, in considering the subject, we can hardly overlook the views of Mr. Bridgman, who compares the process of bone formation and decalcification to what occurs in an electrolytic cell, where, by changing the direction of the current, the electrodes assume precisely opposite functions.

If, then, we could discover the conditions that would preserve the bone tissue, in connection with the dentine, from undergoing decalcification, we might, with every prospect of success, transplant dead teeth, but which, as at present carried out, invariably, we believe, eventually, suffer the fate of ivory pegs introduced into the extremities of bones in disunited fractures. Indeed, this result, although more slowly effected, appears nearly always to follow in those cases where the transplanted or replanted tooth has lost much of its alveolo-dental membrane; whether the excising of a portion of the fang, as advocated by MagitÔt, will prove beneficial or otherwise, remains to be seen.

Porcelain teeth having indentations in their fangs have been suggested, first, we believe, by Mitscherlich,^[3] and again by a recent writer in the Lancet. The former actually attempted two cases, and with the success we should have anticipated, for when after four or five weeks the caoutchouc splint which retained them in situ was removed they immediately followed the splint and fell out. “Ossification had not taken place; the entirely heterogeneous mass of stone had acted as a foreign body, produced granulation and suppuration, and so prevented union.”

In conclusion, we think enough has been stated to show that transplantation or replantation of living teeth, or at all events, of teeth having living alveolo-dental membrane may be exceptionally carried out with benefit to the patient; if the chances of permanent success be not very great the chances of injury are, we believe, small, and have been greatly exaggerated. No such case has come under our observation, but then in all we have witnessed, the transplanted or replanted tooth has never been ligatured or otherwise forcibly retained in its alveolus. We believe many of the cases of failure, as probably those also of bone exfoliation, arose from this procedure. A tooth, after either operation, although at the time perfectly adjusted to its proper position, becomes, after a day or two, elongated from its socket and less firm; the result of effusion into the alveolo-dental membrane and about the tooth; as this material becomes organized it forms, no doubt, the medium of union between the dental and alveolar portions of that membrane. At all events, after a week or so the tooth again recedes into its socket, and as it does so becomes firmer and less sensitive to pressure; if our view be correct, the employment of a ligature or forcible retention of the tooth can only be objectionable. A very different matter, however, will be the adjustment of a plate contrived so as to protect the transplanted or replanted tooth from violence or pressure until its attachment is ensured.