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318 HISTORY OF DEJvTAL SURGERY

located teeth into position."" In reality three appliances were described, con-
sisting of "a self-acting spreading appliance,"" "an inclined plane for jumping
The bite and adjusting the occlusion,"' and "a simple retaining appliance." The
first and most important one consisted in forming metal bands to a single
tooth on each side (usuallj- a bicuspid), and to the band on its lingual surface
soldering an extension wire to rest against a tooth anterior and one or two
posterior to the band. This arrangement made possible the moving of several
teeth by the employment of a single band. To the buccal surface of each band
was soldered a piece of seamless metal tubing about three sixteenths of an inch
in length and set vertically. Thus arranged each band was cemented in place.
The power-producing factor consisted of a piece of hard-drawn German sil-
ver wire (18 per cent nickel), 16 gauge, curved to conform to the anterior part
of the arch and long enough to extend somewhat beyond the anchor teeth. Each
end of the wire was then bent into the form of a double curve, so that when
these vertical ends were slipped into the tubes on the anchor bands the wire
arch would touch, or nearly touch, all of the teeth in its course.
In operation, the wire arch was straightened to form a larger curve, then
pressed into position, when the elasticity of the wire would exert a constant
force resulting in the buccal movement of the teeth on each side included in tlie
operation. Increasing force could be obtained from time to time by remov-
ing the wire arch, flattening its curve and reinserting it in position. If the
anterior teeth were to be retruded coincidently with the widening of the arch,
it was easily accom])lished by bending the spring wire so as to rest tiglitly
against the front teeth. If a single tooth on one side was to be moved buccally,
no extension was made on the lingual side of the band encircling it, while on
the opposite side sufficient resistance was o1)tained l)y including several teetli
as before described. After completion of the operation retention was had by
simply substituting a wire with little or no spring for the one that had accom-
plished the movement.
The simplicity and efficiency of the appliance with its few parts and ease of
construction placed it in striking contrast to the more elaborate and conspic-
uous appliances commonly used to bring about the same results.
During the meeting of the Fourth International Dental Congress, Section
of Orthodontia, in August, 1904, C. A. Hawley presented a paper^ entitled
"Determination of the Normal Arch and Its Application to Orthodontia."
Taking as a basis Dr. Bonwill's geometrical figure of the equilateral tri-
angle, in which two sides represent the distance from the contact point of the
1 Dental Cosmos. Vol. XL"\T:I, p. 541.