Principles and practice of operative dentistry . the cavity at the bottom or by forming smallretaining-pits in the extremities. Cohesive foil orcrystal gold are the best for filling this class of cavi-ties. The filling should be started in one of the ex-tremities, care being taken that the first piece of goldis securely anchored and the balance of the fillingbuilt upon this. Many operators finish such fillingswith platinum-gold foil, as the color is less conspicuousthan pure gold. Figs. 402 and 403 show the locationof fillings of this class. Cavities occurring upon the lingual surface of thein
Principles and practice of operative dentistry . the cavity at the bottom or by forming smallretaining-pits in the extremities. Cohesive foil orcrystal gold are the best for filling this class of cavi-ties. The filling should be started in one of the ex-tremities, care being taken that the first piece of goldis securely anchored and the balance of the fillingbuilt upon this. Many operators finish such fillingswith platinum-gold foil, as the color is less conspicuousthan pure gold. Figs. 402 and 403 show the locationof fillings of this class. Cavities occurring upon the lingual surface of theincisors are generally confined to the laterals, and arethe result of developmental defects, as shown in theimperfect closure of the pit or fissure at the base ofthe cingulum. These cavities are usually small, andare readily filled with a narrow ribbon of non-cohesivefoil and finished with cohesive; or the entire cavitymay be filled with a narrow ribbon of cohesive foil. Such a filling is shownin Fig. 404. Fig. 401. Fig. 400 Johnson lever Caries rarely attacks the morsal edge of the incisors and cuspids, exceptas the result of imperfections in development, from mechanical abrasion,or from traumatic injuries which fracture the enamel. Consequently theoperation of filling is usually confined to artificial cavities, made for thepurpose of protecting the morsal edges against the loss of tooth-substancefrom mechanical or chemical abrasion, or for lengthening the teeth whenit is desired to l open the bite. Cavities prepared for this purpose must have strong retentive form, asfillings of this class are constantly subjected to great stress. Many opera- 18 274 OPEEATIVE DENTISTRY. tors are in the habit of inserting a couple of Mack screws in the arti-ficially formed cavity, one near each extremity, as shown in Fig. add very greatly to the retentive strength of the cavity and makeit very difficult to dislodge such a filling. Care must be exercised in setting the screws no
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectdentist, bookyear1901
