orthodontics

1. Dr Tony Pious

2. The intrusive tooth movement is used in the
correction of overbite.
anterior segment intrusion in deep bite cases
posterior segment intrusion in open bite cases
INTRODUCTION

3. “Intrusion refers to the apical movement of
the geometric center of the root (centroid) in
respect to the occlusal plane or plane based on the
long axis of the tooth.”

4. TYPES
 TRUE INTRUSION OR ABSOLUTE INTRUSION
 RELATIVE INTRUSION
- achieved by preventing eruption of the
incisors, while growth provides vertical space into
which the posteriors erupt.
 PSEUDO-INTRUSION
- labial tipping of an incisor around
its centroid.

5. PRINCIPLES OF INTRUSION
(BURSTONE AJO 1977)
• Controlling force magnitude
• Anterior single point contacts
• Point of force application
• Selective intrusion
• Control of reactive units
• Avoid extrusive mechanics

6. SELECTIVE INTRUSION
 Leveling with a continuous arch or with a sectional
wire can produce undesirable side effects.
 Many times the overbite is corrected not because of
intrusion but by extrusion.

7. AVOID EXTRUSIVE MECHANICS
 Extrusive mechanics such as employing
class II or class III elastics should be
avoided in patient who need genuine
intrusion.

8. THREE PIECE INTRUSION ARCH

9.  Introduced by Shroff, Lindauer and Burstone ( AJO
1995).
 Simultaneous Intrusion and retraction of anterior teeth.
 Consists of:
 Posterior segment
 Anterior segment
 Intrusive cantilever spring

10. Posterior
anchorage unit
Intrusion
cantilever
Anterior
segment
with
posterior
extension

11. RICKETTS UTILITY ARCH

12.  This auxiliary archwire was developed and
refined by Ricketts for bioprogressive therapy.
 The utility arch engages only two molars and
the four incisors. It is commonly known as a 2
X 4 appliance.

13. MATERIALS FOR UTILITY ARCH
 Blue Elgiloy of 0.016" x 0.016"
0.016" x 0.022”
 Dimension in an 0.022" slot.
 A utility arch can even be made with
0.014"
or 0.018" round wires.

14. PARTS OF UTILITY ARCH
Incisal
segment
Posterior
vertical
segment
Vestibular segment
Molar
segment
Anterior
vertical
segment

15.  It produces 60-100 gms on the lower incisors for
intrusion.
 The overall effect is intrusion and possible torqueing
of the lower incisors as well as tipping back of the
molars.
 5 mm space between the anterior border of the
auxiliary tube and the posterior vertical segment of
the utility arch allows tying back the utility arch.

16. Gable bend
Cinching
distally
Tip-back bend

17. • The tip back bend in the
molar segment leads to
posterior tipping of the
first molars.
• Which can be avoided by
placing a gable bend in the
posterior aspect of the
vestibular segment or a
transpalatal arch can be
used.

18. K SIR APPLIANCE
VARUN KALRA( JCO Sept 1998 )

19. • The K-SIR ( Kalra Simultaneous
Intrusion and Retraction ) archwire
is a modification of the segmented
loop mechanics of Burstone and
Nanda
K-SIR archwire: .019“x.025" TMA
archwire with closed U-loops 7mm long
and 2mm wide.

20. • 90o V  bend is placed at the level of each ‘U’ loop
• This ‘V’ bend when placed between first molar & canine during
space closure, creates two equal and opposite moments to
counter the moments caused by the activation forces of closing
loops.

21. • Archwire with off-center 60° V-bend placed about 2mm distal
to U-loop.
• Off-center V-bend creates greater moment on molar, increasing
molar anchorage and intrusion of anterior teeth.

22. • To prevent the buccal
segments from rolling
mesio lingually due to the
force produced by the loop
activation, a 20° anti-
rotation bend is placed in
the archwire just distal to
each U-loop .

23. A. Trial activation performed on each loop.
B. Archwire after trial activation

24. Neutral position of loop
determined with mesial
and distal legs extended
horizontally. In neutral
position, loop is 3.5mm
rather than 2mm wide.

25. A. K-SIR archwire in place prior to cinching back
B. Archwire cinched back to activate loop about 3mm, so that mesial and
distal legs are barely separated.

26. o Simplicity of design
o Less likely to cause tissue impingement.
o 0.019 x 0.025 TMA provides sufficient strength to resist distortion and
enough stiffness to generate the required moments.
o The superior material properties of TMA compared to stainless steel
o Reduced treatment time due to en-masse retraction.
o Frictionless mechanics
o Presence of offset V-bends act as anchor bends
o Molar anchor control is excellent even without headgear.
ADVANTAGES

27. CONNECTICUT INTRUSION ARCH
(By Nanda R, JCO 1998 )
The CTA is fabricated from a nickel titanium alloy

28. oabsolute intrusion of anterior teeth
omolar tip-back for Class II correction
opreparation of posterior anchorage
oincisor flaring
ocorrection of minor open bites
olevelling of anterior occlusal cants
USES

29.  It incorporates the characteristics of the utility arch as
well as those of the conventional intrusion arch.
 Preformed with the appropriate bends
 Two wire sizes are available:
.016 x .022
.017 x .025
 Anterior dimensions of maxillary 34mm & mandibular
28mm, respectively.
 The bypass, located distal to the lateral incisors, is
available in two different lengths to accommodate for
extraction, non-extraction, and mixed dentition cases.

30.  The CIA’s basic mechanism for
force delivery is a V-bend
calibrated to deliver
approximately 40-60g of force.
 Upon insertion, the V-bend lies
just anterior to the molar
brackets.
 When the arch is activated, a
simple force system results,
consisting of a vertical force in
the anterior region and a
moment in the posterior region.

31. THANK YOU