Improvements relating to artificial teeth / [David Genese].

Genese, David.

Date:: 1888

Credit: Improvements relating to artificial teeth / [David Genese]. Source: Wellcome Collection.

2/6 page 2

$2 A.D. 1887.—Nc 17,855. Lake’s Improvements relating to Artificial Teeth. Figure 9 is a central section of Figure 8 showing the bent end of the metal embedded in the tooth. Heretofore in the manufacture of dentures, much annoyance has been experienced by reason of the fracture of the porcelain, in one or more teeth after the plate is finished and the patient has begun to wear it. _ # This accident may be caused by the sudden meeting of two occluding teeth especially where one has received a slight flaw, or it may arise from other causes, such as the strain caused by the capillary action of fluids entering the minute spaces between the teeth and the backing or between the former and the rubber plate. One cause of this defect is unquestionably the common practice of inserting the 10 metal pins, by which the teeth are attached to the plate, in the centre of the tooth or nearly so, thereby giving the latter a constant leverage from both ends, making the base of the tooth the fulcrum. The materials employed having no affinity each supports the other by the bulk of material, and the parts being united by a method causing constant contraction each 15 upon the other the unity of the teeth and the base is broken up, and the whole reliance must be placed upon the small pins or wires which hold by the resistance of their vet heads only. To obviate these defects, 1 construct the teeth and the metal fastenings in the following manner * 20 In the drawing the reference numeral 1 denotes the body of the tooth in which is formed a cylindrical cavity or opening 2, extending from the base to the grinding surface. A channel 3 is cut from the labial surface of the tooth toward the centre, entering the cylindrical opening 2. The numeral 4 denotes the metal backing of the tooth, which lines the cavity 2, the double thickness of the metal being carried 25 through the channel 3. and the ends being folded over upon the back of the tooth as shown at 5. This construction, as will readily appear, permits the free and independent expansion of both metal and porcelain. It also gives a spring space running to the back of the tooth embracing and pro- 30 tecting the part which receives the greatest pressure in mastication, at the same time it unites the tooth to the plate by a large central hold-fast, beside the ordinary backing which is already burned to the tooth and will therefore not shrink or expand again like the ordinary backing riveted to the pin teeth. I may employ a double cylindrical cavity 2a as shown in Figure 4 and place the 35 metal therein in a similar manner, the only difference being in the duplication of the cavity 2, and channel 3. In the thin elongated incisor teeth, where the form of the tooth is such as to prevent the formation of a central opening of any appreciable diameter, I flatten the tubular part 6 of the backing and mold the tooth thereon, as seen in Figure 5. By beveling 40 off the base of the tooth, as shown in Figure 6 the attachment of the backing is not disturbed or weakened, and an equally extensive point of attachment to the plate is afforded. I may substitute for the form of backing heretofore described that shown in b igure 7 consisting of a metal plate 8 having one end 9 turned over at an angle and 45 perforated at 10. The tooth is molded upon this backing, the bent end 9, being near the point of the tooth. The paste of which the tooth is formed fills the perforation 10 and holds the backing in place, the subsequent firing completing the union of the parts. Having now particularly described and ascertained the nature of my said invention, and in what manner the same is to be performed as communicated to me 50 by my foreign correspondent I declare that what I claim is. First. A tooth tor artificial dentures, the same having one or more vertical cavities oi openings extended from the roof to the grinding surface, and a channel in rear of the^opening, substantially as described. Second. A tooth tor artificial dentures, having one or more vertical cavities or 55 openings extending entirely through the body of the tooth, and a channel in rear$

Improvements relating to artificial teeth / [David Genese].

Licence and re-use

Contents