Introduction to Orthodontics Fifth Year

1. Fixed appliance
-Fixed app. Are those attached to the teeth
-The fixed attachments are placed by either banding or bonding
technique
-Since the fixed app. Is attached to the teeth, it's capable of producing a
wide range of action in comparison to the removable app.
Indication of fixed app.
-correction of mild to moderate skeletal discrepancies
-intrusion/extrusion of teeth
-correction of rotation
-overbite reduction
-Closure of an openbite
-Multiple tooth movement required in one arch
-Active closure of extraction space
-Edward Angle developed the E-arch. From early 1900s.Bands were
placed only on the molar teeth. ligatures from heavy labial arch were
used to bring to the line of occlusion (E-arch)
-the E-arch was capable only of tipping teeth to a new position, thus
angle began placing bands on other teeth and used vertical tube on each
tooth into which a soldered from a smaller arch wire was placed.(pin and
tube appliance)
-this app. Proved impractical in clinical use. The relatively heavy base
arch meant that spring properties were poor, and the problem therefore
was compounded because many small adjustments were needed
-the angle next appliance modified the tube on each tooth to provide a
vertically positioned rectangular slot behind the tube. A ribbon arch of
10x20 gold wire was placed into the slot and held with pins.(ribbon arch)

2. To overcome the deficiencies of the ribbon arch, Angle reoriented the
slot from vertical to horizontal and inserted a rectangular wire rotated
90 degree to orientation it had with ribbon arch (edgewise). the
dimensions of the slot were altered to 22x28 precious metal wire was
used
the rectangle wire was tied into a rectangular slot with ligatures, making
excellent control of root position possible
development of fixed appliance
-standard Edgewise appliance
-early 1900s
-Begg Appliance:
-R.Begg had been taught use of the ribbon arch app. at Angle school.
Working indecently in Australia, he set out to adapt ribbon arch for
better control of root position
-His adaptation took three forms:
1- he replaced the precious metal ribbon arch with 16 mil st.steel
2- he retained the original ribbon arch bracket, but turned it upside
down, so that it pointed gingivally rather than occlusaly
3- he added auxiliary springs for better root control
- combination of Begg and edgewise app. have been proposed on many
occasions
-one is to use bracket with Begg slot and an edgewise slot: the other is to
use a modified bracket that allows tipping in one direction, so that the
rectangular slot is available for both root uprighting and torque

3. Components of the fixed Appliance
- bands
-molar tubes
-brackets
-buccal tube
-arch wires
- auxiliaries: wlastomeric products. Coil spring. Lingual arches. Extra-oral
app.
Brackets:
Acc to:
1-welded/bonded
2-material: st.steel, Cr-cobalt, gold, plastic, ceramic, or silicon
3-esthetic: metal/esthetic brackets
4-self-ligating/conventional ligated
5-narroow/wide
6-slot size
-To produce the required movements. Different bends have to be
incorporated in the arch wire
-1st order bends: made in the plane of archwire to compensate for
differing tooth width
-2nd order bend: made in the vertical plane to achieve correct
mesiodistal angulation or tilt of teeth

4. 3-3rd order bend: applicable to rectangular archwires only. They are
made by twisting the plane of the wire
-To (torque) is the least efficient tooth movement using orthodontic app.
Significance of accurate bracket/band positioning
-precise tooth positioning
-optimal effect of "pre-adustment"
-occlusion
-esthetic
-stability
-bands:
Posterior attachment
-Molar tube
-Arch wires:
Acc to material
-St.st
- Ni Ti
-TMA
-Elgioly

5. Elastic properties
Elastic properties-strength analysis
3 points on the stress strain graph can be represented to explain
"Strength"
1-proportional limit
2-yield strength
3-ultimate tensile strength
-proportional limit
Point at which first deformation is seen
Proportional limit --- elastic limit
-yield strength
Experimentally it's difficult to measure the proportional limit
0.1% of plastic deformation
-ultimate tensile strength
Max. load a wire can substain
Evolution o orthodontic wire material
Stainless steel(entered dentistry-1920:world war I
-1930's-popular—refinement of drawing process
-1934-opposition *Emil Herbst
Angle-steel as ligature wire …>
gold>SS
-1950's- type 300 series-most orthodontic app.
17-25% Cr
8-25% Ni

6. Balance Fe
Cabalt chromium
-1950s-Elgin watch co
-rocky mountain orthodontics-Elgiloy TM
Various tempers:
Red: hard & resilient
Green: semi-resilient
Yellow: slightly less formable but ductile
Blue: soft & formable
-nickel titanium alloys (late 1960s)
Buehler-office of navy-alloy-shape memory effect (SME)
-Nitinol-nickel titanium naval ordnance laboratory
Deformed,clamped,heated&cooled-specified shape
1970s George Andreasen. UNITEK-orthodontics
50:50 Ni and Ti
-pseudoelastic Niti
Pseuudoelasticity- stress induced >>austenitc martensitic phase
transformation
Copper NiTi
cu…5-6%
cr… 0.2- .5%

7. thermoelastic NiTi-Miura
thermoelasticity-thermal induce >>austenitic martensitic
phase transformation
sentalloy –GAC
chiness NiTi-general research institute for Non ferrous metals
Japanese NiTi-FURUKAWA electric co Ltd
-Bet titanium TMA
Early 1980s
Composition
-Ti—80%
-molybdenum- 11.5%
-zirconium-6%
-Tin- 4.5%
Fiber reinforced polymeric composites
-next generation of esthetic archwires
-aerospace industry
-pultrusion- round + rectangular

8. Classification based on cross section
ABCDE
Direct bonding:
-tooth prep
-prophy with pumice
-etch 30 second with 37% phosphoric acid
-moisture control is a must?
-determine bracket position
-bracket placement
-align and push firmly into place
-express excess composite
-bracket base should be flat against tooth
Indirect bonding
-accurate bracket placement
-less chair time
-more hygienic
Cementation:
-ZPH CEMENT
-ZPC CEMENT
-GI CEMENT

9. Ligation:
Elastic module:
Single or chain
Lingual orthodontics
-developed by Dr.Kinjita in Japan in 1976 to satisfy the need of [patients
who practical martial arts
-craven Kurz patented his lingual bracket in the Us in 1976, and with
ORMCO developed pliers and other instruments
-early successes were tempered by difficulty of the technique and the
poor results which it rendered
Advantages: orthodontist
-treat pts who refuse labial tx.
-better evaluation of esthetics during tx.
-protrusive, expansive and intrusive movement are easier
-"splint effect" encourages deep bite correction and relaxes muscles
Anterior leveling
-upper arch (.016 Cu—Niti)
-lower arch (.016 Cu-NiTi)