The Dental cosmos . ition. The gum beingfirmly attached at other points, it is evident that if the rubber-dam bestretched over such a tooth, it will in consequence of the pediclesa, a span across, and occupy the line b, b, so that the cavity borderwill be below the dam. In many cases it is not only impossible toforce the dam down with a ligature and keep it there, but the effortto do so, by causing hemorrhage, compels the abandonment of theoperation at that sitting. Even where one succeeds in pressing therubber and ligature below the border, it rises again when tied, becausebecoming taut it mu
The Dental cosmos . ition. The gum beingfirmly attached at other points, it is evident that if the rubber-dam bestretched over such a tooth, it will in consequence of the pediclesa, a span across, and occupy the line b, b, so that the cavity borderwill be below the dam. In many cases it is not only impossible toforce the dam down with a ligature and keep it there, but the effortto do so, by causing hemorrhage, compels the abandonment of theoperation at that sitting. Even where one succeeds in pressing therubber and ligature below the border, it rises again when tied, becausebecoming taut it must assume the straight line b, b ; if it is not madetaut, leakage will occur. To overcome this difficulty, it has beensuggested to use copper wire as a ligature. R In a few mild cases this works very wire ligature is applied about the neckof the tooth, and the ends twisted till with the silk or flax, it follows the lineb, b, but with a suitable instrument it maynow be forced below the border of the. cavity, carrying the dam with it, and, being fi \ f \ • *\metallic, it will retain its position. Where this cannot be accomplished, it becomes impossible to fillthe entire cavity with gold. Two courses are open,—either amalgamalone must be depended upon, or amalgam may be used up to, andslightly above the line b, b, the rest of the cavity being filled with goldat a subsequent sitting. In either case a margin more nearly perfectwill be obtained if the napkin is used instead of the rubber-dam, thegum being occasionally mopped with bibulous paper or spunk duringthe operation. This will be more specially alluded to in discussingthe manipulation of amalgams. When it has been decided to employ the dam, it is requisite that itshould be so placed that the patient may suffer least, and the operatorhave the greatest facility for obtaining access to all parts of the first desideratum is that a sufficient number of teeth should beembraced so that all folds of th
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Keywords: ., bookauthor, bookcentury1800, bookdecade1890, booksubjectdentistry
