Columbia University School of Dental and Oral Surgery - Dental Columbian Yearbook (New York, NY)

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CODOS, i 9 i 8 Fig. I Fig. 2 Twenty-Three

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C O D O S , i 9 i 8 imottsirattott in Jugulating Appltanr? By Victor Hugo Jackson (M.A., M.D., D.D.S., New York). HE new anchorage of appliances requires that a thin, broad collar with a buccal lug of triangu- lar shape, like a door latch located to rest near the gum at the center of the tooth, be cemented to the last erupted molar on ea ch side ofthe dental arch, and a similar collar with a buccal lug be cemented to each of the cuspids, or if the cuspid is absent, the collar be cemented to one of the other anterior teeth. Often lingual lugs are used for these purposes. (See Fig. i.) When the collars are cemented to the anchorage teeth, an impression of the arch is taken and accurate models are prepared, on which an appliance is made. The metal parts of an appliance are known as partial-clasp, spring-clasp, base-wire and springs. Of each of the last two, there are several forms. The metals employed are usually of German silver spring wire. Spring wire containing more than 20j3er cent, of nickel (known as silver nickel) is generally used, and when carefully drawn it is usually sufficiently springy. A partial-clasp of 18K. gold plate-metal No. 36 U. S. standard wire gauge, shaped with a contour- ing plier, is fitted to the lingual surface of each of the cuspids, bicuspids and molars of the model on each side of the arch. The foundation of an appliance is a base-wire usually of a rather large diameter. The size or gauge of the base-wire is chosen according to the age of the patient and density of the bone. A spring-wire No. 13 U. S. standard wire G. being used for a child of four years, No. 11 base-wire for a child of eight years, No. 10 for a child twelve years of age, or for an adult; for the adult occasionally No. 9 G. is employed. In any case where the anterior part of the dental arch requires lateral expansion and the distal part of the arch does not require lateral expansion, the body of the appliance is made by arranging a large base- wire to cross the distal part of the arch opposite the last molars following the palatine curve. The ends are bent forward to form arms, extending from the last molars to the cuspids, resting on the partial-clasps near the gum on the lingual side of the teeth, to which they are finally soldered. These ends of the base-wire are made less bulky by dressing them with a file, especially near the ends, or at locations that will not lessen their strength. Twcnty- ' J ' zvi

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CODOS, 191 8 PALATAL BASE-WIRE. When both the distal and the mesial parts of the arch require lateral expansion, a similar base-wire is first formed into a U-shaped loop extending forward as far as can be in the deep part of the palatal vault, with the sides extending backward to the distal part ofthe last molar, and then be curved forward, forming arms extending from the last molars to the cuspids. This latter form of base-wire is known as a palatal base- wire with a U-shaped loop. The action of the appliance with the simple palatin base-wire for causing the lateral expansion of the anterior part of the arch is brought about by pulling outward on the front ends of the arms of the appli- ance that rests on the cuspids, at regular intervals; bending the base-wire a little and reinserting the appli- ance, gradually moves those teeth forward. ' . LINGUAL BASE-WIRE For making appliances for the lower arch a lingual base-wire is employed. The lingual base-wire is shaped to follow the lingual curve of the lower arch near the margin of the gum extending backward to about the center of the last molar of the arch, where the ends are bent forward, forming arms to cross the partial clasps near the gum as described for making an upper appliance. For completing the anchorage of the appliance, a wire-clasp made of No. 19 or 20 gauge spring-wire is shaped to pass from the lingual base-wire around the last molar to the buccal side to rest between the lug on the collar described and the gum. The ends of the wire-clasps always terminate in a loop, similar to a small hook, so that in unlocking the device one ' s fingers will not be pricked or injured in springing out- ward the end of the wire-clasp for unlocking the device, also the hooks on the clasps are utilized when neces- sary for supporting rubber equalizing bands for equalizing the dental arches antero-posterially. Similar wire-clasps of No. 20 gauge are shaped to pass from the lingual base-wire over the arch at the junction of the lateral incisor and cuspid to the buccal side, to engage with the lug on the collar, one on each of the cuspids. In some instances it is not necessary to cement a collar to the molar, as if the tooth is well erupted, a wire-clasp or plate spring-clasp is sufficient. Finger-springs for moving the teeth are arranged to extend from the anchorage portions, or arms of the appliance to the lingual or to the labial side of any of the teeth for moving them outward or inward, for their rotation, elevation, depression, etc. Twenty-Four