Swa strap up & leveling

Straight wire appliance
Principles, strap up &
levelling.
www.indiandentalacademy.com

Principles.
 Each br. – customised for tooth type.
 Preangulated slots – accomplish MD tooth tip.
 Bases of the br. Inclined – proper tooth torque.
 Bases – contoured – verrt. & horizontally.
 Dist. From slot base to br. Base varies for
each tooth type.
 Built in guidance – min. archwire manipulation.
 Guidance features consistent with fnl. Occl.

Strap Up.
 Most imp. Mech. Procedure.
 Most imp. Aspect of trt. After diagnosis & trt.
Planning.
 Built in features – expressed only if br. Are
accurately placed.
 Improper br. Placement – extra months of
finishing..
 Natural settlijg & tooth positioners – unrealistic
options.

 Bracketing must be performed by
orthodontists.
 2 systems:
Direct:
Light cure – reduced time
immediate force application possible.
Self cure – Faster.
replacement of 1or 2 loose br.
Indirect Bonding:
 Greater precision
 Lesser chair side time.

Andrews system of br. Placement.
 Br. Placed on FA with twin wings – straddling
the FACC & center of slot at FA point.
 FACC: Vertical line alont the most prominent
Portion – in the central area of the facial surface
of tooth crown.
 FACC for molars: Vertical line along the
dominant buccal groove- at M-D & O-G center.
In molars br. & tubes are placed // to occl.
Surface.

 Advantages of new systems:
 Yields uniform br. Siting.
FACC & FA points are easliy identifiable & not
sub. To environmental hazards.
 Crowns used as base – our work is keyed to
crown.
 Not affected by variation in tooth size.
If br. Is positioned at fixed dist. From the incisal
edge / cusp tip,
Angulation of slot to crown – varies with varying
crown varies with varying crown sizes.

 Errors in br. Positioning.
 Horizontal errors
 Axial or paralleling errors.
 Thickness errors.
 Vertical errors.

Horizontal errors:
Due to br. Placement mesial or distal to FA pt.
Head to improper tooth location.
Avoided by –
 Visualizing FACC from facial & incisal / occl.
Surface..
 Drawing line through FACC.

 Axial or Paralleling errors:
Due to br. Wings not // FACC
- head to imp. Crown tip.
 Avoided same as before.
 Thickness errors.
Due to excess adhesive – left under one portion.
Contour of tooth doesn’t correspond to contour
pf br. Base.
- heads to imp. Torque & rotn.
 Avoided by pressing the br. Against the tooth at
placement.
 Acurately contouring the br. base

 Vertical Errors.
Due to pl. – occl. Or gingival to FA point.
Extrusion or intrusion of teeth.
Torque & in out errors.
Uncommon in fully erupted & anatomically
normal teeth.
 Commonly occurs in:
 Partially erupted teeth.
 Teeth with gingival infl.
 Teeth with palatally displ. Roots.
 Teeth with facially displ. Roots.
 Teeth with occl. Or incisal fr.

 Vertical placement of bracket is altered
length of individual crown – incisal to FA pt
length of individual crown – gingival to FA pt
For aesthetic & functional purposes
Minor error in torque & in-out rel’ns corrected in
finishing stages
Crowns with long tapered buccal cusps-
gingival to FA pt
Otherwise adjacent marginal ridges will not be
aligned

 Bracket placement errors in individual teeth
Upper central incisor
Horizontal errors – not major problem
Vertical errors – common & must be avoided
Paralleling errors – common due to keying from incisal
edge rather than long axis of crown
Upper lateral incisor
Vertical errors – common
Owing to small size,must be placed gingival to
FA pt
Paralleling errors – common due to abnormal
Shape
Horizontal errors- if rounded in shape

 Upper canines:
 Vertical error – common when canine is not
fully erupted.
 Horizontal error – more frequently than
incisors due to greater curvature.
 // errors also occur.
 Upper premolars:
 Vertical error – common as they are partly
erupted.
 Horizontal errors – same frequency as
canines.
 // errors – if 2nd
PM band is not seated properly
in the distal side.

 Upper molars:
 // error – vert. Ref line is buccal groove.
 Buccal groove angulated at 5° to occl. Plane.
If 5° tip br./ tube Is used – band must be seated
more on mesial than distal surfce.
Error avided by 0° tip br/tube which is welded
onto band that is seated // to occl. Plane.
 Vertical error- placed too gingivally.
 Horizontal error – uncommon.

 Lower incisors:
 Vertical error – ususally placed too incisally –
opening bites in finishing stages.
 Horizontal errors – uncommon.
 // error – leads to inter proximal spaces b/s
incisors in gingival area.
 Lower canines:
 Vertical error – placed too incisally.
 Horizontal error – occurs.
 // errors – uncommon.

 Lower premolars:
 Vertical errors – placed too occl. Due to
incomplete eruption.
marginal ridg discrepancy b/w PM & 1st
Molar.
 // error – also causes marginal ridge disc.
- due to incomplete seating of band on
distal side.

 Lower molars.
 Vertical errors – placed too gingivaly to avoid
occl. Interference- in 1st
molar,
too occl in 2nd
molar.
 // error.- due to more gingival placement of br.
On mesial end.
 Rotational errors – few.

Aids in reducing bracketing errors:
 Positioning jigs.
 Brackt placement charts.
 Proper separation.

 Levelling & aligning.
Division of trt. Into stages – originally in Begg tech.
St. wire tech – divided iinto 3 stages.
 Levelling & aligning.
 Correction of molar reln.& space closure.
 Finishing.

Levelling & Aligning:
Defn. comprises of tooth movt. Needed to
achieve passive engagement of plain rect.
Wire of 19 x 25 dimn. With std. Archform into
correctly placed preadjusted 0.022 slot br.sys.
 Goals:
 Correct vertical disc.
 Bring malposed tooeth into arch.
 Control A-P posn. Of incisors
 Control width of arches – post.
 Control arch form.

Principles in choice of leveling & aligning wires:
 Provide light continuous forces – efficent tooth
tipping movt.
 Move freely within the br. Slot.
2-4 mm clearance needed.
0.014 ideal in 0.018 slot.
loose lig. Necessary.

 Rect. Wires, even resilent 17 x 25 niti avoided.
to prevent undesirable root movt.
alignment becomes slower & more damaging to
roots.
 In asymmetric crowding cases – comb. Of rigid
wire & springy aux. wire to be used.

 Properties of levelling & aligning wires
Excellent strength
Excellent springiness
Long range of action
The above properties are affected by
A/wire material
Size of wire
Interbracket distance

 A/wire material
Niti & TMA – better comb of strength &
springiness
Niti – added adv of flat LDR
SS – multistranded or looped
 Size of wire
A- Niti – wire size doesn’t affect properties
affected by manu. preparation
Imp with regards to slot size

 Levelling & aligning wires
Superelastic Niti
Remarkable range & low LDR
.014 or .016 in .018 slot which delivers 50 gm force
Avoid tying too tightly
Drawbacks:
Expensive
Travel around the arch
Thermal Niti-
Totally passive when cold,making engagement easier
At mouth temp.,becomes active

 TMA & SS – properties greatly affected by wire size
As size , strength , springiness
Smallest size wire with adequate strength used
 Multistranded – strength added, springiness relatively
unaffected
 Distance between attachments
Affected by bracket width
Affects strength & springiness of wire

Multistranded SS
.0175 both in.018 & .022 slots
Indicated when large range is not necessary
Adv:
Cheap
Equally effective
Disadv:
Force levels variable
Pat discomfirt greater
Addl. clinical time

M-Niti,Coaxial SS & looped small diam SS
Std. Of trt few years ago
Obsolete now
As expensive as A-Niti
But performance of cheaper multistranded wire

Alignement in symmetrical
crowding cases
 Pm extn cases
Severe crowding
Retract canines first by –
Segmental retraction loops in 19 x 25 TMA in high
anchorage cases
Sliding along .016 wire
Moderate crowding cases
Simultaneously tip canines distally & align incisors by
Looped a/wires – Drag loop by Stoner
Loops placed mesial & distal to canine

 Non-extn cases
Tying superelastic wire to slot is effective
& space is created by moving incisors further
from molars
Looped multistranded wire with loops mesial
to molars & wire held ant’r to incisors before it
is tied in

Alignement in asymmetrical
crowding cases
 A/wire has to be rigid where teeth are aligned
& springy where crowding is present
 2 methods :
Looped SS a/wire with loop in area of
crowding- formerly used
Superelastic aux in conjunction with stiff SS
main wire
Lighter forces- useful in adults
Greater control against distortion of arch form

Special problems in alignement
 Crossbite Correction
Ant’r crossbite:
Mild crossbite corrected in L & A stage
Expression of severe crowding
Correction involves opening of space &
bringing into proper position in arch
Occlusal interference may make this difficult-
Ant’r bite plate needed

Pos’r crossbite
Skeletal pos’r crossbite –
Transverse max expn by opening midpalatal suture
Achieved by -
Slow expn
Rapid expn
100% success before 15 yrs of age
Often crowding is present that warrants extn,
Extn performed after expn cause
pm’s act as anchorage for lateral expn
addl space might make extn unnecessary

Types of expanders :
Haas type – metal framework + plastic shelves
Hyrax – metal framework only
Minn type – less force
The above expanders can be either bonded or
banded

 Dental pos’r crossbite
Correction achieved with
Heavy labial arch :
Inner bow of facebow- in Cl II cases &
when molars are tipped lingually
Heavy labial aux – if distal movt of molars not
desired

Exp’n lingual arch :
Quad helix- if anchorage is of no concern
Transpalatal lingual arches –
36 mil SS
32 x 32 SS/TMA
Crosselastics :
From lingual of U/molar to buccal of L/molar
Strong extrusive component,
Accentuating  in vertical dimension

 Impacted / unerupted teeth
Trt consists of :
Surgical exposure
Attachment to tooth
Mechanical apprpaches for aligning
unerupted tooth

 Surgical exposure
Important for tooth to erupt through attached gingiva
If labially impacted,flap must be raised from alveolar
crest
Flap design not critical in palatally impacted tooth
Once obstacle is removed, tooth might erupt without
intervention if root form’n is incomplete

 Method of attachment
Bonding of button or hook to exposed labial
surface
Smaller size, better than std bracket
Gold chain tied to attachment
Mechanical approaches for aligning the tooth
Should begin immediately
Space creation & alignement of other teeth must be
complete
Aligning aux or magnetic attraction can be used

 Impacted L/2nd
molar
Occurs as a result of ortho trt
Tooth has to be moved pos’rly & uprighted
If mildly tipped –
Separators sufficient
If severely tipped –
Aux spring extending into
Embrasure between 1st
& 2nd
molar
Buccal tube bonded on 2nd
molar after exposure

 Levelling
Can occur by
Extrusion of pos’rs/relative intrusion
Intrusion of incisors/absolute intrusion
Combination of the two

 Levelling by extrusion
By continuous a/wire with
exagerrated curve of spee in max &
reverse of curve of spee in mand
18 slot,narrow bracekts
16mil steel – usually sufficient
16 or 18mil M-Niti – in severe cases
17 x 25 mil TMA/ steel aux. For complete levelling
22 slot, wide brackets –
16 mil steel – initial levelling
18 mil steel – final levelling.

 Levelling by intr.
 Succesful int. – light continuous forces
directed to tooth apex
 Intrusion not to be pitted against extrusion
 Two methods –
 By pass arches.
 Segmented base wire with aux. depressing arch.

 Bypass arches
Continuous wires that bypass pm’s
Indicated in growing patients
Mechanical principle –
Incisor intrusion pitted against uprighting & distal
tipping of molars
Two types –
Mulligan’s levelling a/wire - .016 wire with anchor
bends in 2x4 appliance
Rickett’s utility arch

 Segmented a/wires for levelling
Depend on establishing stabilized pos’r
segments & controlling pt. of force application
against ant’r segment
Full size rectangular wire in pos’r segment,
Rectangular TMA in ant’r segment &
Depressing arch 18x25SS/19x25TMA-
From aux molar tube to gingival of incisors(passive)
Applies light force when brought beneath incisor
brackets

Conclusion
 Strap up is the most imp. Step in the straight
wire technique, that will ultimately reflect in
the finish of the case.
 Extra attention spend during this stage will
reduce amount of labour during finishing
stages.

Swa strap up & leveling

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