Dental cosmos . serve the tooth, which is the ultimate object. In cylin-der work there is very little cohesion between the leaves of foil, butthere is a better adaptation to the cavity wall. To illustrate : Take a cylinder of soft foil between the thumb andfinger, and squeeze it quite hard. Look at it afterward, and a well-defined imprint of the rugae of the finger-tips will be seen, whilecohesive foil similarly treated gives a far less clear impression of theserugae. I will first describe the mode of making the cylinder. A piece of foil—one-half or one-third or even a whole sheet—isplaced upo
Dental cosmos . serve the tooth, which is the ultimate object. In cylin-der work there is very little cohesion between the leaves of foil, butthere is a better adaptation to the cavity wall. To illustrate : Take a cylinder of soft foil between the thumb andfinger, and squeeze it quite hard. Look at it afterward, and a well-defined imprint of the rugae of the finger-tips will be seen, whilecohesive foil similarly treated gives a far less clear impression of theserugae. I will first describe the mode of making the cylinder. A piece of foil—one-half or one-third or even a whole sheet—isplaced upon a pad of some elastic material, and a wire of a certainsize is placed on its edge, and with the fingers the gold is rolled uponand around the wire (see Fig. i). The size of this wire governs thelength of the cylinder, which should be somewhat greater than thedepth of the cavity, so that the gold, before final condensation, willprotrude above the margin of the wall. The wire being withdrawn, Fig. i. Fig. the roll thus produced is wound upon the point, or if a particularlysoft cylinder is desired, upon the body, of a square or five-sided watch-makers broach (Fig. 2). When this roll is large enough, theunwound gold is torn away from that which is on the broach, andthat which is on the broach, which is the cylinder, is removed, and withgentle pressure slightly flattened between the thumb and finger (). Various lengths and sizes according to the cavity to be filledare made, and the gold is ready for use. In preparing the cavity, there is absolutely no necessity of a retain-ing pit; a slight groove, shown by the dotted line in Figs. 7 and 8, isall that is needed, and in crown cavities in which the grinding-surfacealone is involved, even this precaution is not necessary if the wallsare parallel. The form of point to be used is shown in Figs. 5 and6. The former is round, while the latter is flat and are the characteristic forms, but of course there wil
Size: 1970px × 1268px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthor, bookcentury1800, bookdecade1890, booksubjectdentistry
