When a set of two, three, four, or more teeth was to be applied, Fauchard first prepared them separately and then united them together by means of one or two threads of gold or silver in such a manner that the set formed at last a single piece, which was then fixed to the natural teeth. When the piece consisted of several teeth it was reinforced with a small plate of gold or silver fixed to its inside by means of small tacks of the same metal riveted on one side to the plate, on the other to the front part of each tooth. The author remarks that a similar prosthetic piece lasted longer than those previously described, but required proportionately much more work and much greater expense. He adds that, by employing this plate, one can even dispense with threading and fixing the teeth together with gold or silver wire; but that it was then necessary to make a horizontal groove at the back of each tooth corresponding to the width and thickness of the plate, which could be fitted into the serial groove and fixed to each single tooth by means of two small rivets.[462] At other times the prosthesis was carried out in a single piece of material (ivory, hippopotamus tusk, etc.) that was carved in such a manner as to substitute exactly the teeth wanting, it being fixed to the natural teeth in the usual manner. Fauchard sometimes left the dental roots in their place (if they were in good condition), applying upon them artificial crowns, which he either bound to the neighboring teeth or fixed with screws to the respective roots. “When one wishes to apply an artificial crown to the root of a natural tooth, one files away the part of the root that emerges above the gum, and even more if possible. One then removes, with proper instruments, all that is decayed in the root itself; after which one stops the root canal with lead and fits the base of the artificial tooth to the root in such a manner that they correspond perfectly to each other. One drills one or two holes in the tooth through which to pass the ends of a thread, which serves to fasten it to the natural teeth on each side of it, as described above. “If the root canal has been very considerably enlarged by the carious process, so as to have rendered it necessary to stop it, the root being, nevertheless, still quite steady, one bores a small hole in the lead as deep and as straight as possible, without, however, penetrating farther down than the root canal. The artificial crown is then united to the root by a pivot in the manner I shall now describe.”[463]