FORCES IN STAINLESS STEEL, TIMOLIUM, CNA INTRUSION ARCHES WITH DIFFERENT BENDING MAGNITUDES
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AIM • To compare intrusive forces in stainless steel, timolium, and CNA , V bend intrusion arches with different magnitudes of flexion.
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OBJECTIVES • Intrusion is the most difficult and soughtafter movement in orthodontics • Intrusion needs a constant and very light forces for it to happen without much damage to tooth root • A ideal arch wire with long range of action and low load deflection rate will suit intrusion. www.indiandentalacademy.com
Materials • SS, Timolium, CNA rectangular wires of caliber of .017’’ x .025’’-10 arches for each alloy • PHANTOM UPPER JAW • RULERS • PROTRACTOR • UPPER MOLAR BANDS WITH BUCCAL TUBE (TRIPLE) .022 SLOT • .016 ss wire www.indiandentalacademy.com
EXCLUSION CRITERIA • CTA Niti arch wire is not included as it is difficult to bend and is available only in preformed form
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METHODOLOGY • The use of a phantom upper jaw with acrylic teeth and an enlarged gum area allowed the fixing of three rulers, one at midline and two in the cuspid region facilitating bilateral control during arch execution.
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• The first molars had tubes fixed to them and the centre of the upper incisor crowns were marked with steel wire .016” to simulate the bracket slot line. • This option was adopted in the event of bracket interference during the test, impeding force measurement.
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• The V-bend, also called anchor bend, for intrusion was made in the region between the first molar and second premolar. • Use of a template length arch ruler allowed all folds to be made at a distance of 48 mm from midline.
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• A protractor was used so that all folds had a 45° inclination. • The folds thus created produced a 20 mm deflection in relation to the line representing the bracket slots.
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• In order to favor the site for fitting the hook for testing traction and preventing displacement of hook in the arch, small folds in the form of a “uâ€? were made in the midline region.
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• The use of the same phantom jaw for all arches of different alloys guaranteed standardization of possible error, since it would be of equal magnitude in the alloys studied.
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• The extremities of the arches were inserted in the tube accessories of the first molars and bent in the posterior region. • A hook was then fixed to the load cell and connected to the arch in the midline region to secure it
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• Trial speed was standardized at 10 mm/min. • The load magnitudes and the displacements (5, 10, 15 and 20 mm) were registered by a computer coupled to the machine. (INSTRON)
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progress • Introduction completed and got approved • Materials ordered to libral traders • Review of literature writing in progress
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