A long cylindrical tube, of sufficient stoutness to afford the requisite strength, forms the handle of this instrument, and being hollow, permits a chisel to work freely within it. Indeed the chisel would work too freely if some means were not employed to steady it, therefore a large bulb, which is filled with packing and constitutes a stuffing box, is fixed at one end, and by pressing against the shaft of the chisel prevents it from being too readily displaced; though at the same time it allows of the cutting agent being propelled, with all the force that could be desired. The bulb likewise serves another purpose, as it gives the operator a firm grasp, and prevents the danger of the hold being lost when the instrument is struck. At the opposite end of the handle there is a frame, the further part or base of which is sharp upon theinner side; within this frame the chisel plays, and by it therefore is securely guarded. When the instrument is used, the chisel is drawn back to about the extent represented in the foregoing wood-cut, and into the space thus created is introduced the projecting tooth, which consequently is encircled on every side, and both before and behind is between two cutting edges. The operator then firmly grasps the handle, and applies to it such force as he calculates will be sufficient to counteract the effect of that blow which he is about to deliver. With a hammer of adequate weight he now strikes the head of the chisel, and the tooth flies off. The operation is instantaneous, and so far it is an advantage; but beyond this is the safety which accompanies it. The softer parts cannot be wounded, for the action is strictly circumscribed in every direction, but the main principle of the invention remains to be pointed out. However great may be the force employed, no sensible jar is communicated to the jaw. The writer has held between his fingers a tooth which has been divided with this instrument at a single blow, and the shock was so trivial as to be unworthy of any notice. The concussion is received upon the guardresting against the hind part of the tooth, and beyond that annoyance which the accompanying sound may excite, the horse suffers no inconvenience. Fracture of the alveolar processes is rendered impossible, and the ease with which the instrument is applied, considerably enhances its value. It would, however, be of service only when the tooth was large, and the entire body projected above the level of the other molars. It is not unfrequent for portions of the grinders, worn into various angles, to present themselves, and to occasion very serious effects upon the health of the horse. To remove these is of no less importance than to cut off the more regular and larger substance; and Mr. Gowing has produced instruments capable of fulfilling these intentions. In the first place he has improved upon the old guarded chisel, concerning the danger and inefficiency of which, remarks have been already made.
In the old tool the cutting surface was small, being rarely more than three quarters of an inch broad,and the blunt sides afforded rather a show of protection than any positive security. Mr. Gowing has increased the breadth needed to make the chisel useful, and he has also added two falling sides, that, dropping over the lateral surfaces of the molars, guide the instrument, which works as in a groove. More steadiness is thus obtained, and the operator, consequently, can act with decision. The new chisel, however, is not intended to be used alone; if singly employed, it might do some damage, and fracture almost as readily be induced as formerly. To prevent such an accident other aids were imperative, and perceiving this, the instrument, which the following wood-cut represents, was invented by Mr. Gowing.
It is carved, so as to be suited to the shape of the horse’s mouth, and at one end has a handle, while at the other is a cutting edge, between two circular guards, which prevent any injury being done to the softer parts. When a shelving projection of tooth is to be removed, this instrument is introduced into themouth, and the sharp edge is lodged against the back of the tooth, when it is given to an assistant to hold, while the operator, taking the chisel, proceeds to employ it in the way before mentioned. The object here is two-fold. In the first place, the chisel is restrained or prevented from being urged against the posterior of the mouth by the stroke of the hammer; and in the next place, the concussion is received upon the instrument, and taken from the jaw. Sometimes when a tooth is loose, but not either of sufficient size, or fitting shape, for the application of the forceps, the sharp edge can be got to a certain degree behind, and under it, when by a wrenching action it can be either elevated or forced out. There are, however, cases in which none of the instruments hitherto described answer so well as might be wished. Frequently little pieces or sharp corners of teeth project, and to remove these, demands more variety of position on the part of the operator, than the previous instruments will admit of. To meet this difficulty, Mr. Gowing, who to the surgery of the teeth has devoted more study than any person has hitherto bestowed upon the subject, invented the instrument represented in the annexed wood-cut.
In principle it is similar to the one which preceded it, but the handle being at the side instead of above, it can be adapted to those irregularities which the former would not readily catch. The operator can move it about at his pleasure, and where nicety is required, he can, with it, take off particles, such as the previous instruments would not enable him to touch. It consists of a cutting edge, guarded on one side by the handle, and on the other by a rounded projection. In the manner of its application, it is similar to the last, and like that is held by an assistant when used in operation. For many points this is of much service, but in order to be prepared for every difficulty, a pair of them suited to the opposite sides are required. Possessed of these the veterinary surgeon has, for the first time, what may be regarded as a complete set of dental instruments, with which he can operate, with ease to himself, and without hazard to his patient. Themouth rasp is all that he requires, in addition to what has been depicted; and thus armed, he can overcome obstacles which once bid defiance to his skill.
FINIS.
G. J. & E. Wilson, Printers, George Court, Piccadilly.