1. CLINICAL CONSIDERATIONSCLINICAL CONSIDERATIONS OF
ORTHODONTIC ARCHOF ORTHODONTIC ARCH WIRESWIRES PART II A SEMINAR BY
DR.NANDA KISHORE REDDY Post graduate
2. INTRODUCTION In the orthodontic treatment all along there
has been a pursuit to bring about efficacious means of moving teeth
In the present day orthodontist has a wide armamentarium of wires
in clinical use.in some situations newer space age wires are used
and in some the older conventional wires For proper usage of wires
and appropriate selection of an arch wire ,a comprehensive
knowledge of the properties of the wires and their comparative
usefulness in various stages of treatment is necessary.an attempt
towards this has been made in this presentation
3. NOMOGRAMS Nomograms are fixed charts which display the
mathematical functions,provided each scale is adjusted in space
appropriately with normal range from 1 When constructed properly
the relationship between its parameters will be given in a straight
line,in other words the extended line between the two properties
will yield the third Strength = stiffness x range
4. Conclusion With the nomograms shown it is clear that the
stainless steel wire is the stiffer wire with low range of action
and more strength Ni- Ti wires has good range of action but with
decreased stiffness and strength Beta titanium has good amount of
range of action but less stiffer than that of the s.s
5. Contents in the topic Arch wires and their requirements in
aligning Alignment in various techniques Leveling arch wires Types
of leveling in various techniques Types of retraction and arch wire
selection Finishing arch wires
6. The behavior of an arch wire depends upon : The diameter of
the wire The composition of the wire The length and configuration
of the inter bracket span The width of the brackets Friction
between the arch wire and the bracket channel
7. Principles in the choice of alignment arch wires Should be
providing light continuous forces to produce the most efficient
tipping movements Should be able to move freely in the brackets for
mesio distal sliding along an arch wire and at least 0.002 inch
clearance between the arch wire and the bracket is needed and 0.004
inch clearance is desirable ,it is also known as intra bracket
space
8. Rectangular arch wires particularly with a tight fit in the
bracket slot could affect the position of the root apex should be
avoided the principle is that it is better to to tip around the
position to bring alignment rather than displacing the root
apices.although the most resilient arch wires could be used in
alignment stage ,that is unwise because this arch wire will create
unnecessary and undesirable root movement ,so round wires are
preferred According to another school of thought initial leveling
and aligning should be carried out by controlling the torque from
the onset of the treatment .hence rectangular arch wires are
preferred from the onset of the treatment Thermo dynamic rect.
Ni-Ti wires and rect. Multi stranded wires are used by Andersen G.F
et.al
9. Variables in arch wire selection Arch wire material Inter
bracket span Techniquetype of bracket used as it influences the
inter bracket span and in certain cases where the incisor root
position is critical.
10. CHARACTERISTIC S.S Elgiloy NiTi TMA COMPOSITION MODULUS OF
ELASTICITY HIGH HIGH LOW MODER.. FORMABILITY GOOD V.GOOD POOR GOOD
SOLDER/ WELDABLE yes yes not not RANGE moder moder good v.good
SHAPE MEMORY no no yes no SUPER ELASTICITY no no yes no RESILIENCY
moder good good V good STRENGTH V good good poor good
11. Inter bracket span The span of wire between two brackets is
known as inter bracket span.the action of the wire is interrupted
,in the confinement of the bracket.in essence the bracket is a dead
spot that functions as an annealed area.The wider the bracket the
greater the dead area and less amount of working area will be
present.decreasing the working area decreases the wire
effectiveness,and lessens the mechanical efficiency.In a longer
span between the brackets,the wire will be more flexible and
therefore will bend further before permanent set occurs.
12. Inter bracket span has clinical implications such as :
Patient comfort Precision of hook placement on the arch wire
Precision of loop position Precision of placing the bends in the
arch wire Number of round wires required Length of time the round
wires must be used Size of the first rectangular wire Ease of
placing the torque Amount of torque which can be used Ease of
getting correct arch form Effectiveness of torque Total number of
times the arch wires must be removed Total time spent in treating
the case
13. The greatest possible distance between the brackets is
required in order to have the treatment relate most favorably to
all the above considerations.so therefore in a single bracket
appliances the inter bracket span is more,there by less force and
greater range of action of the arch wires can be realized.in twin
bracket appliances the inter bracket span is reduced,there by force
and range of action of arch wires are decreased
14. ALIGNMENT ARCHES FOR 0.018 INCH EDGE WISE APPLIANCE 0.002
inch clearance should be ideal clearance between wire and
bracket,to bring about alignment 0.016 inch diameter wire is the
largest wire that should be considered in an 0.018 slot system
Multi stranded steel wires 0.015 twist wire (3x0.005)gives adequate
clearance,but its physical properties are markedly inferior to
0.0175 multi stranded wire Nickel Titanium wires 0.016 inch
Japanese Ni-Ti which has super elastic properties is most ideal
.0.016 inch nitinol (work hardened nickel titanium alloy)is also
useful. 0.016 ni-ti is superior when single brackets are used ,
0.014 ni-ti is beneficial when twin brackets are used as inter
bracket span is reduced.
15. Stainless steel wire with loops 0.014 inch wire with loops
is regularly used as the functions of the loop are to Reduce force
,and increase the range by adding the wire in the inter bracket
span Force of the loop can be reduced by coiling the wire at the
apex one or more times Types of loops used: Vertical loops-
labiolingual movement Horizontal loops a)boot type-occluso gingival
movement b)T-loop c)closed horizontal loop Box loops-comb.of
vertical and horizontal segments allowing free mov. In all planes
of space provides
16. ALIGNMENT ARCHES FOR 0.022 INCH EDGE WISE APPLIANCE In
0.022 edge wise appliance twin brackets are generally used on all
teeth.the reduced inter bracket span makes the arch wires stiffer
and loops have to be located very precisely Multi stranded wires
0.0175 twist wire is excellent choice as an intial alignment arch
wire 0.0185 respond wire can be replaced as it is more stiffer and
the irregular surface and small clearance prevents free
sliding
17. Nickel Titanium wires 0.016 Ni Ti with 0.006 clearance is
ideal.super elastic Ni Tiis preferred followed by work hardened Ni
Ti Stain less steel wire with loops Loops are not of much use In
the 0.022 edge wise.in crowded cases individual retraction of
canines with loops can be under taken before alignment
18. ALIGNMENT IN 0.018 INCH VARI SIMPLEX DISCIPLINE In
maxillary arch 0.016 inch Ni Ti wire is used.in mandibular arch
0.017x0.025 D-rectangular wire is used in minimally crowded arch,to
obtain immediate torque control.in moderate to severe crowding
cases 0.016x 0.022 inch D rectangular is used ALIGNMENT IN 0.018
INCH STRAIGHT WIRE APPLIANCE 0.016 inch Ni Ti is the most suitable
wire for alignment in 0.018 inch wire appliance ALIGNMENT IN 0.022
INCH STRAIGHT WIRE APPLIANCE 0.018 Ni Ti is the most suitable wire
for alignment in 0.022 inch straight wire appliance
19. ALIGNMENT IN BEGG APPLIANCE The narrow brackets used in
begg technique provides maximum inter bracket span,hence alignment
and leveling are much faster and occurs almost simultaneously
Stiffness of the wires used in begg technique is far less ,so
initial alignment occurs rapidly 0.016 inch round Australian
special plus Multiple loops are used in severely crowded cases
Co-ax wire along with 0.016 inch wire is moderately used in
moderately crowded cases Nitinol wire is also used in aligning the
crowded teeth
20. ALIGNMENT IN TIP EDGE TECHNIQUE 0.016 inch round arch wire
in 0.022 inch tip edge bracket slot 36 degrees tipping range
permits arch wire engagement
21. ALIGNMENT IN COMBINATION TECHNIQUE Similar to that of the
begg technique utilizing 0.016 inch round wires with or with out
loops or in conjunction with multi stranded wires using vertical
slot of the bracket
22. LEVELLING Is a procedure in which molars and premolars are
brought in the same plane as the incisors Supra eruption of the
molars and pre molars Intrusion of anteriors Combination of both
Leveling by extrusion(relative intrusion) Exaggerated curve of spee
in the maxillary arch wire and reverse curve of spee is placed in
the lower arch wire
23. 0.018 SLOT EDGE WISE 0.022 EDGE WISE APPLIANCE 0.016 inch
stainless steel wire with reverse curve of spee and accentuated
curve of spee is used in in lower and upper arch wires respectively
LEVELING IN VARI SIMPLEX DISCIPLINE In non extraction cases TMA is
an intermediate arch wire.it is used when slight rotations are
still present and the arch is beginning to level
0.017x0.017,0.016x0.022 and 0.17x 0.025TMA wires are used depending
on the clinical situation Torque control and leveling are the
primary functions of intermediate wire
24. 0.018 AND 0.022 INCH STRAIGHT WIRE APPLIANCE Leveling is
carried out similar to that of 0.018 and 0.022 inch edge wise
appliance with reverse curve of spee LEVELING IN BEGG TECHNIQUE The
anchor bends placed in the arch wire causes intrusion of the
anterior teeth and extrusion of the posterior teeth aided with
class II elastics leading to the bite opening or leveling with
0.016 inch stainless steel round wire
25. Leveling in Tip edge Technique Leveling in tip edge
technique is brought about by using 0.016 inch Australian special
plus wire with anchor bends Combination technique Leveling is done
similar to that of begg technique LEVELLING BY TRUE INTRUSION Light
continuous force directed towards the apex of the tooth Avoid
pitting intrusion of one tooth against extrusion of its neighbor
This can be accomplished by utility arches and bye pass arches
26. TMA is well suited as a utility arch for three primary
responses 1.high formability 2.enhanced resilience ,a single
activation is all that is required for vertical correction
3.reduced load deflection rate,the incisor torque control can be
obtained while staying within accepted force levels
27. Utility arch is made up of 0.016x 0.016 blue elgiloy
wire,which is formed heat treated and used regardless of the slot
of the brackets Type A leveling Type B leveling Type C
leveling
28. RETRACTION AND SPACE CLOSURE Retraction mechanics can be
divided into two Friction or sliding mechanics Frictionless or loop
mechanics Mechanism of friction mechanics
29. Arch wire in the bracket..moment of the force.elastic
component gives force for retraction.together the moment to force
ratio gives retraction of the teeth Moment distal tipping of the
crownbinding moment of couple.distal root torqueas the tooth
uprights moment decreases untill the wire no longer bindsthen the
crown slides along the arch wire ,untill the distal crown tipping
causes binding Magnitude of the torquing moment depends on the
size,shape and material of the arch wire The larger the load
deflection rate of the wire the greater the force resulting from
its deflection and the greater the moment produced
30. Selection of arch wire for sliding mechanics Arch wire and
bracket friction Co-Cr,beta titanium and nickel titanium wires
produce more friction than that of stainless steel wires due to
surface topography of the wires 0.014,or 0.016 inch s.s wires with
lowest friction can be distorted by elastic forces 0.018 or 0.017x
0.025 s.s wires are less susceptible for distortion by the elastics
0.019 x 0.025 inch s.s wire is more ideal for sliding mechanics in
0.022 inch slot
31. Friction less mechanics or loop mechanics In this mechanics
teeth are moved with out the brackets sliding along the arch wire
retraction is accomplished with loops or springs Principles in
selection of the arch wire for loop design 1.simplest loop
preferred with less complex configuration 2.spring should posses a
reasonable range of activation
32. Arch wire material considerations for retraction arch wires
Stain less steel vertical loop has a limited activation range ,the
use of alternative materials and cross sections can change the
level of force and increase the activation range M/F ratio is not
influenced by arch wire material,to obtain higher moment to force
ratios increase the amount of pre activation-higher amount of pre
activation is possible if a material with low modulus of elasticity
and relatively high yield strength can be substituted for stainless
steel
33. TMA (beta titanium) Modulus of elasticity is less than that
of the s.s allowing larger pre activation angles The cross section
of the wire can be reduced there by increasing the activation and
extending the M/F ratio Elastic modulus is of 71.7 Gpa Yeild
strength is of 860-1170Mpa Resulting in large deflections and low
forces when compared to that of stain less steel
34. Segmental arch approach to space closure It comprises of
TMA spring of two different cross sections of wire 0.018 inch round
T-loop welded to a 0.017 x 0.025 inch base arch wire called as
composite spring
35. Space closure in vari simplex discipline In maxillary arch
0.016 inch stain less steel round wire is used for retraction of
cuspids followed by 0.018x 0.025 closing loop wire is used In
mandibular arch 0.016x 0.022 inch closing loop stain less steel
arch wire is used
36. Space closure in begg technique Two step retraction First
stage is the distal tipping of the anterior crowns brought about by
0.016 inch round wire and elastics as only point contact is present
between bracket and wire,no moment is produced by wire bracket
retraction Second stage involves lingual torquing of the anterior
roots
37. Ribbon arch wires and Dual flex arch wires
38. Space closure in Tip edge
39. Wire sequence according to different orthodontic
concepts
40. FINISHING Finishing procedures include Torque control Root
paralleling Correction of vertical relation ships
41. Torque control Two factors determine the amount of torque
that will be expressed by any rectangular wire in rectangular
bracket slot 1.The inclination for the rectangular arch wire to the
bracket slot. 2.Tightness of the fit between the arch wire and the
bracket.
42. Torque effect due to the tightness of the fit between the
arch wire and bracket Square or rectangular arch wires are
manufactured from round wires by a process of rolling rather than
drawing Turks head is the device for rolling to the desired
dimensions Edges of the wire remain rounded after rolling
process,resulting in a edge bevelcritical factor for torque
expressionlargest edge bevels are observed in beta titanium
segments due to mechanical and wear properties of this alloy
43. Use of ribbon arch wires Gives less force and are less
stiffer than edge wires and are easy to ligate with out undue force
dissipation Smaller dimension wires can fill the bracket slot to
give the maximum torque in the appliance The torque force in the
arch wire is is delivered depending on the length of the span ,and
degree of deflection and not the wire orientation.therefore ribbon
wise wires can be used effectively in edge wise brackets
44. Rectangular arch wires for torque in 0.018 appliance:
0.018edge wise appliance 0.017x0.025 steel arch wire is feasable
0.018 vari simplex appliance 0.017x 0.025 steel arch wire 0.018
straight wire appliance 0.017x 0.025 stain less steel arch wire
Rectangular arch wires for torque in 0.022 appliance 0.022 edge
wise appliance: Full dimension rectangular arch wires are too stiff
for effective torquing 1.piggy back arches 2.0.022 x 0.016ssw
ribbon wise arch wire can be used 3. Burstones torquing auxillary
for additional torquing of central incisors .0.021x 0.025 ssw is
used
45. 0.022 straight wire appliance : 0.021 x 0.025beta titanium
arch wire is ideal for finishing taking the advantage of the
greater resilience of the material Less effective alternative is
0.021 x 0.025 rectangular braided steel wire is used 0.021x 0.028,
0.021x 0.025 ssw is not advised becoz of its high stiffness and the
resulting extremely high forces and short range of action
46. TITANIUM NIOBIUM Made from nickel free titanium niobium
alloy,the wires are soft and easy to form,yet have the same working
range as stainless steel The stiffness in bending is half that of
the stainless steel,and torsion is roughly one third These
characteristics enable the clinician to use titanium niobium for
creative bends with out excessive force levels of steel wires The
weld ability of these wires is good making possible to weld two
different dimensions creating a differentiated force systems Thus
making the titanium niobium arch wire most ideal wire in
finishing
47. Root paralleling at the extraction sites Up righting Root
paralleling in 0.018 edge wise appliance 0.017 x0.025 steel wire is
used as finishing wire which has enough flexibility to engage
narrow brackets Correction of vertical relation ships Anterior over
bite is more likely a problem in the finishing stage. rect Arch
wires can be used as an auxillary intrusion arch 0.016 or 0.018
round wires are used after finishing to create occlusal
stabilization
48. Torque control in begg technique The torquing auxillary
used will be of 0.014round wire which is used as a piggy back arch
on a 0.020round wire This auxillary contacts the labial surfaces of
the incisors near the gingival margin creating the necessary couple
and creating the necessary moment to force ratio
49. CONCLUSION The progress of orthodontic treatment is
dependent on the type of wires used and the attachments on the
teeth From the beginning the quest was to find new materials to
bring about more physiologic tooth movement,less chair side timeand
more comfort to the patient In the present day treatment has become
simpler and is carried out in a logical sequence of arch wires
Super elasticity and shape memory of wires have helped the
orthodontist to bring about more efficient tooth movement The
future lies in finding new materials which give more physiological
forces and are able to give better stability where required and
flexibility in appropriate areas of treatment
50. FUTUROLOGY With the advent in the materials,researchers
have found that square arch wires would be more efficient in
achieving the treatment results TURBO WIRE HEAT ACTIVATED NITINOL
SQUARE ARCH WIRE With the use of square arch wires the treatment
time is reduced as the torque is expressed from the day one of the
treatment,and the number of arch wires used is reduced to two or
three
