This document discusses various techniques for intruding teeth in orthodontics. It begins by defining intrusion and describing how it differs from other tooth movements like tipping. Deep overbites can be corrected through intrusion of anterior teeth or other movements. The principles of intrusion mechanics include applying light continuous forces through the center of resistance and using devices that create statically determinate force systems. Various intrusion appliances are described, including utility arches, tipback springs, continuous and segmented intrusion arches. Key biomechanical concepts for intrusion like controlling reactive forces and avoiding extrusion are also summarized.

1. INTRUSION MECHANICS IN ORTHODONTICS
BY
Dr. GEJO JOHNS
Dr. GEJO JOHNS

2. CONTENTS
1. Introduction
2. Major principles of intrusion
3. Biomechanics involved
4. Various intrusion appliances
A. Head gear
B. Rickett’s utility arch
C. Tipback springs ( intrusion springs)
D. Burstone’s continuous intrusion arch.
E. Burstone’s three piece intrusion arch
F. K-sir (kalra simultaneous intrusion and retraction)
G. Connecticut intrusion arch
H. PG retraction spring
I. Translation arch
J. Lingual arch for intruding and uprighting lower incisors
K. Temporary Anchorage Devices
5. References
Dr. GEJO JOHNS

3. Introduction
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. - Burstone
Marcotte defines intrusion as the” tooth movement that occurs in an axial (apical) direction and whose
center of rotation lies at infinity. It is an axial type of translation”
Nicolai as “ translational form of tooth movement directed apically and parallel to the long axis”
Dr. GEJO JOHNS

4. Correction of the deep overbite can be accomplished in a number of ways depending on the initial
diagnosis and treatment objectives. Deep bite can be corrected by various tooth movements which
include:
 Extrusion of posterior teeth
 Uprighting of posterior teeth
 Increasing the inclination of incisors
 Intrusion of anterior teeth
 Combination of one or two of the above tooth movements
Dr. GEJO JOHNS

5. Extrusion of the posterior teeth will result in increased lower facial height, steepening of the
occlusal plane, downward and backward rotation of the mandible, resulting in worsening of the
class II skeletal relationship.
Intrusion of anterior teeth to correct deep overbite may be indicated in patients with unaesthetic
excessive maxillary incisor showing at rest position of the lip (5-8mm)
Dr. GEJO JOHNS

6. Pseudo intrusion refer to the labial tipping of the incisor around the centroid.
Relative intrusion – Deep bite correction by extrusion of posterior teeth rather than
true intrusion of the anterior teeth
Dr. GEJO JOHNS

7. Biomechanics In Intrusion
True intrusion is obtained by applying a single intrusive force through the
center of resistance of the anterior teeth.
The precise selection of the point of application of the intrusive force with
respect to the axial inclination of the incisors is critical and will define the
type of tooth movement
If the incisors are flared and the intrusive force is applied anterior to the
Cres further flaring occurs so to prevent this force should be applied distally
in order to direct the force passes through the Cres
Dr. GEJO JOHNS

8. Major Principles Of Intrusion
Six major principle of intrusion should be followed; if genuine intrusion and greater control of force system is
needed:
1. Controlling force magnitude and constancy.
2. Anterior single point contacts.
3. Point of force application.
4. Selective intrusion.
5. Control of reactive units.
6. Avoiding extrusive mechanics.
Burstone CJ. Deep overbite correction by intrusion. Am J orthod 1977;72:1-22 Dr. GEJO JOHNS

9. Controlling Force Magnitude And Constancy
True intrusion
If the magnitude of force are too great Rate of intrusion will not increase
Low Magnitude Of force
Rate of resorption will increase
Reciprocal effect on posterior
anchorage
Dr. GEJO JOHNS

10. In order to maintain a constant force during intrusion, wire with a low load deflection rate should be used.
If a high load deflection spring is used for intrusion as teeth moves, a rapid drop in force magnitude
occurs, so that optimal force may be only momentarily reached.
Dr. GEJO JOHNS

11. Anterior Single Point Contacts
By having a single point of force application on the incisors, the clinician
knows more positively the full force system acting at the incisor segment
and buccal tube, there by producing a statically determinant system.
By placing the intrusive arch into the brackets produces a statically
indeterminant system, which prevents the orthodontist from knowing exactly
what type of force he is delivering
Intrusion arch into the bracket Torque to the anterior segment
introduced
Dr. GEJO JOHNS

12. Labial root torque
Increases the magnitude of intrusive force
Increases the side effects on anchorage unit
Lingual root torque
Decreases the intrusive force
Dr. GEJO JOHNS

13. POINT OF FORCE APPLICATION
Passing through center of resistance Intrusion of incisor segment
Passing labial to the center of resistance Flares the crown more labially
Dr. GEJO JOHNS

14. 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.
Dr. GEJO JOHNS

15. Control Of The Reactive Unit
Two basic side effects should be anticipated from intrusive mechanics
 From the lateral view a moment is created which tends to alter the plane of occlusion of the buccal
segment and therefore in the upper arch, the plane is steepened.
1.The force are kept as low as possible
2.Teeth in the buccal segment are rigidly connected and the right and the left buccal stabilizing segment are
connected
3.So add more teeth for anchorage
4.Do as much retraction as possible to decrease the length of moment arm
Dr. GEJO JOHNS

16.  Second major side effect produced by an intrusive arch can be seen from the frontal view with an
intrusive force acting on the incisors, there is an equal and opposite extrusive force acting at the molars.
 since the extrusive force is acting buccally at the tube, a moment is created that tends to tip the crowns
lingually and roots buccally.
One of the functions of the lingual arch is to resist side effects
Dr. GEJO JOHNS

17. Avoiding Extrusive Mechanics
Extrusive mechanics should be avoided if one is to accomplish genuine intrusion.
One of the classic situation for inadvertently erupting incisors which have been intruded or are going to be
intruded is placement of continuous arch wire.
Dr. GEJO JOHNS

18. It is wise to intrude the maxillary incisors to a significant degree prior to any retraction:
1. Bite opening is achieved by moving maxillary incisors into the alveolus.
2. The potential for increasing a gummy smile is minimized.
3. The unfavorable tipping of the occlusal cant will not be as common.
4. It will minimize the chances of moving the apices into the dense cortical bone.
5. There will be a reduction in the total amount of class II elastics that will be required.
6. The torquing requirements will be reduced.
Dr. GEJO JOHNS

19. Intrusion Force
Intrusion Per-Side Total in Midline
Upper central inciosr 15-20(gm) 30-40(gm)
Upper central and
lateral incisor
30-40(gm) 60-80(gm)
Upper central lateral
and canine
60(gm) 120(gm)
Lower central incisor 12.5(gm) 25(gm)
Lower central and
lateral incisor
25(gm) 50(gm)
Lower central lateral
and canine
50(gm) 100(gm)
Dr. Charles J.Burstone., Modern Edgewise Mechanics and The Segmental Arch Technique Dr. GEJO JOHNS

20. Proffit suggested 10-20 grams of force needed for intrusion.
Bench, Gugino and Hilgers in 1978, advocated intrusive force of 15 to 20 grams per lower incisor
and 60 to 80 grams for all four lower incisors.
Lui and Herschelb in 1981 suggested use of 80 to 100 grams of force for four incisors intrusion.
Though there has been many opinions regarding an ideal force for intrusion, all recognize the need
for light continuous force
Dr. GEJO JOHNS

21. Dr.GEJO JOHNS

22. J Hook Head Gear
The extraoral traction force can be attached anteriorly by means of j –hook to
the arch wire or to a hook soldered to the arch wire.
J –hook can be applied to the maxillary teeth to retract and intrude the
maxillary incisor teeth.
The line of force passing mesial and apical to the center of resistance causes
intrusion and distalize upper incisors.
Head Gear + Maxillary intrusion splint = For whole Arch Intrusion.
Dr. GEJO JOHNS

23. • Placed immediately posterior to the 2nd premolar bracket
• Bent so that when inserted into the buccal tubes the anterior section of the archwire lies in the buccal sulci
Causes intrusion of anteriors
ANCHORAGE BENDS / TIP BACK BENDS.
Dr. GEJO JOHNS

24. GABLE BEND
Modified bite opening bend given in the arch wire distal to the canine
This tends to cause relative extrusion of canines and intrusion of central and laterals
Dr. GEJO JOHNS

25. Hocevara’s Intrusion Bend
Given by Richard A. Hocevar,
Bite opening bends are placed on either side of the canines, which results in more intrusion of central incisors
and relative extrusion of laterals and canines
Hocevar RA. Orthodontic force systems: Technical refinements for increased efficiency. American Journal of
Orthodontics and Dentofacial Orthopedics. 1982 Jan 1;81(1):1-1. Dr. GEJO JOHNS

26. BITE OPENING CURVES
• Reverse curve of spee correct the deep bite by extrusion of the posteriors and intrusion
and flaring of the anteriors
Dr. GEJO JOHNS

27. Intrusion Arches
Intrusion can be accomplished in two ways with intrusion arches.
1. With continuous archwire that by passes the premolars and canine teeth.
2. With segmented base archwire. So that there is no connection along the arch between the anterior
and posterior segments and an auxiliary depressing arch.
Dr.GEJO JOHNS

28. Until 1980, intrusion arches were made of stainless steel wire with helical spring in front of molars to reduce the
load deflection rate
In 1980, beta-titanium alloys replaced Stainless Steel , eliminating the need for a helical spring due to the
titanium wires lower stiffness.
Preformed NiTi wires (Connecticut intrusion arch) were introduced in 1998. These pre-activated and pre-
caliberated wires deliver a force of 35-45gm.
Burstone first describe intrusion arch mechanics as a part of the segmented arch technique in 1950s
The basic mechanism of intrusion consists of three parts a posterior anchorage unit, an anterior segment, an
intrusion arch spring .
Dr. GEJO JOHNS

29. 1. Ricket’s Utility Arch
2. Tipback Springs ( Intrusion Springs)
3. Burstone’s Continuous Intrusion Arch.
4. Burstone’s Three Piece Intrusion Arch
5. K-Sir (Kalra Simultaneous Intrusion And Retraction)
6. Connecticut Intrusion Arch
7. PG Retraction Spring
8. Translation Arch
9. Lingual Arch For Intruding And Uprighting Lower Incisors
Dr. GEJO JOHNS

30. Rickett’s Utility Arch
McNamara JA Jr. Utility arches. J clin orthod 1986;20:p.452-456.Dr. GEJO JOHNS

31. UtilityArch
Utility arch designed by Robert M. Ricketts in the early 1950’s and has been popularized as an
integral part of bio-progressive therapy.
Continuous wire that extends across both buccal segments, but engages only the 1stpermanent
molars and four incisors .
Dr. GEJO JOHNS

32. Material For Utility Arch
Dimension in an 0.022" slot
Non heat treated Blue Elgiloy
0.016" x 0.016" or 0.016" x 0.022”(mandible)
0.016" x 0.022” (maxilla)
Dimension in an 0.022" slot
Blue Elgiloy 0.019" x 0.019”
Dr.GEJO JOHNS

33. A. Molar segments
B. Posterior vertical segment
C. Vestibular segment
D. Anterior vertical segment
E. Incisal segment.
Dr. GEJO JOHNS

34. Molar Segment
It extends into a tube on the 1st molar.
This segment may be cut flush with the end of the tube or may be bend gingivally if the utility arch is to be
tied back.
When utility arches are used in combination with full arch appliances, it is necessary to have auxiliary
tubes located in the gingival portion of the 1st molar bands
Dr. GEJO JOHNS

35. Posterior Vertical Segment
It is formed by making a 90° bend with 142 arch forming pliers.
Posterior step typically is 3-4mm in length
Dr. GEJO JOHNS

36. Vestibular Or Horizontal Segment
Vestibular segment is formed by placing a right angle bend at the inferior portion of posterior
vertical segment. The wire then passes antero-inferiorly along gingival margin.
Dr. GEJO JOHNS

37. ANTERIOR VERTICAL SEGMENTS
• Anterior vertical segments should be about 5-8mm in length.
Dr. GEJO JOHNS

38. INCISAL SEGMENT
• Final 90° bend creates the incisal segment that should lie passively in the brackets of anterior
teeth
Dr. GEJO JOHNS

39. Intrusion Utility Arch
Intrusion utility arch is similar in design to passive utility arch , arch is activated to intrude the
anterior teeth.
Utility arch should produces 100 grams of force on the maxillary incisors, force level considered
ideal for maxillary incisor intrusion
Dr. GEJO JOHNS

40. ACTIVATION
• Occlusally directed gable bend in the posterior portion of the vestibular
segment of the arch wire
• Bench has advocated an alternative method of activation of utility arch to
produce intrusion. This type of activation involves placing a tip – back bend in
the molar segment .
• Thus activating the utility arch by placing a gable bend in the posterior aspect
of the vestibular segment seems to avoid unwanted tipping
Dr. GEJO JOHNS

41. BIO – MECHANICS OF INTRUSION ARCHES
• One couple systems
• Two couple systems
Dr. GEJO JOHNS

42. ONE COUPLE APPLIANCES—STATICALLY DETERMINATE
SYSTEMS
• The end that is tied as a point contact
• The end which is engaged in the bracket slot a force and
a couple
• 1-couple system couple is generated only at the site of
full engagement.
• It is statically determinate magnitudes of the
forces and moments produced can be determined clinically
after the appliance is inserted into the bracket.
Dr. GEJO JOHNS

43. TWO COUPLE APPLIANCES - STATICALLY INDETERMINATE
SYSTEMS
• Both the ends of the wire is engaged into brackets
• Magnitudes of the forces and moments produced can not be determined clinically after the appliance is
inserted into the bracket.
• Because of the inability to measure force systems produced by 2-couple appliances clinically, they are
referred to as being statically indeterminate
Dr. GEJO JOHNS

44. TIP BACK SPRINGS (INTRUSION SPRINGS)
• By Burston
• The upper and lower arches have to be leveled and aligned and a rigid stainless steel wire, preferably
0.017”x 0.025” dimension is engaged.
• Anchor is reinforced by TPA and lingual holding arch
• The intrusion springs are made from 0.017" x 0.025" TMA wire without a helix or 0.017" x 0.025" stainless
steel wire with a helix so that forces can be made optimal for intrusion
Dr. GEJO JOHNS

45. Wire is bend gingivally mesial to the molar tube and then a helix is formed.
The mesial end of the spring is bend into a hook and is engaged distal to lateral incisor (activation)
Dr. GEJO JOHNS

46. Burstone Intrusion Arch
The intrusion arch, as described by burstone in 1977, is significantly different in its force deliver
because it is not engaged in the incisor brackets
Burstone CJ. Deep overbite correction by intrusion. Am J Orthod 1977;72:1-22
Dr. GEJO JOHNS

47. The basic mechanism for intrusion consists of three parts:
1. The posterior anchorage unit.
2. The anterior segment.
3. The intrusion arch itself.
Dr. GEJO JOHNS

48. POSTERIOR ANCHORAGE UNIT
• Early in treatment the posterior teeth are aligned and joined together
with a buccal stabilizing segment of heavy wire.
• Right and left posterior segments are joined together across the arch by
means of a transpalatal arch in the maxilla and a lingual arch in the
mandible.
• Whenever possible, at least the first molars and second premolars should be
used and the addition of other teeth would further enhance the anchorage
potential
Dr. GEJO JOHNS

49. INTRUSIVE ARCH SPRING
• The intrusive arch consists of an 0.016 x 0.022 inch or 0.017 x 0.025 inch TMA.
• A step down is placed to the canine bracket to avoid this bracket upon activation of the intrusion arch.
Dr. GEJO JOHNS

50. ANTERIOR SEGMENT
• Initial alignment of anterior teeth is not necessary when performing intrusion.
• Intrusive spring is tied to the wings of the brackets of incisor not into the slot.
• Formed to fit the teeth to be intruded
Dr. GEJO JOHNS

51. Three-piece Intrusion Arch
Segmented approach to simultaneous intrusion and space closure: biomechanics of three piece base arch
appliance” Am J Orthod dentofac Orthop 1995:107: 136-43
Dr. GEJO JOHNS

52. In patients with proclined incisors, a continuous intrusion arch tied at the midline
cannot be used because the force system generated tends to worsen the axial
inclination of the anterior teeth
So the selection of the point of application of the intrusive force with respect to the
center of resistance of the anterior segment is important to precisely define the type of
tooth movement that will occur
Dr. GEJO JOHNS

53. Consists of
 Posterior anchorage segment
 Anterior segment with posterior extension
 Intrusive cantilevers
Sometimes chain elastics
Dr.GEJO JOHNS

54. Anterior Segment With Posterior Extension
It is bent gingivally distal to the laterals and then bent horizontally creating a step of approximately 3
mm
Distal part extends to distal end of canine bracket where it forms a hook 0.021 x 0.025 ss
Posterior Segment
Aligned posteriors
0.017 X 0.025 SS
TPA can be given for more consolidation
Dr. GEJO JOHNS

55. Cantilever Or Intrusion Spring
Made from 0.017" x 0.025" TMA wire.
The wire is first bent gingivally mesial to the molar tube and then a helix is formed. On the mesial end the cantilever,
hook is bent through which the intrusion force can be applied to the anterior segment.
The cantilever is then activated by the making a bend mesial to the helix at the molar tube, and the cinched
Dr. GEJO JOHNS

56. A small distal force can be added by attaching chain elastic from the hook of anterior segment to the
molar tube to facilitate simultaneous intrusion and retraction of the anteriors on each side
Dr. GEJO JOHNS

57. Biomechanics
Intrusive force through Cres will intrude incisor along line of action of this force.
An intrusive force perpendicular to the distal extension and through Cres will have the same effect.
Dr. GEJO JOHNS

58. To obtain a line of action of the intrusive force through the center of resistance and parallel to the long
axis of the incisors, the point of force application must be more anterior and a small distal force should
be given
Dr. GEJO JOHNS

59. If the intrusive force is placed farther distally and an appropriate small distal force is applied, intrusion and
simultaneous retraction of the anterior teeth occurs because of the tip back (clockwise) moment created around the
center of resistance of the anterior segment consisting of four incisors.
Dr. GEJO JOHNS

60. K- SIR APPLIANCE
Varun Kalra, “simultaneous intrusion and retraction of the anterior teeth” JCO 1998 p535-540.
Dr. GEJO JOHNS

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

62. 90° bends placed in archwire at level of U-loops.
Centered 90° V-bend creates two equal and opposite moments (red) that counter the
moments (green) produced by activation forces.
Dr. GEJO JOHNS

63. 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.
Dr. GEJO JOHNS

64. 20° antirotation bends placed in archwire just distal to U-loops.
Dr. GEJO JOHNS

65. Trial activation performed on each loop..
Archwire after trial activation.
Dr. GEJO JOHNS

66. K-SIR archwire in place prior to cinching back.
First molar and second premolar are connected by segment of .019"x .025" TMA wire.
Archwire cinched back to activate loop about 3mm, so that mesial and distal legs are barely separated.
Dr. GEJO JOHNS

67. The Connecticut Intrusion Arch
JCO, VOLUME 32 : NUMBER 12 : PAGES (708-715) 1998 RAVINDRA NANDA, ROBERT MARZBAN, ANDREW
KUHLBERG, DMD, MDS
Dr.GEJO JOHNS

68. The Connecticut Intrusion Arch
The CTA is fabricated from a nickel titanium alloy.
It incorporates the characteristics of utility arch as well as those of the conventional intrusion arch.
Two wire size are available 0.016” x 0.022” and 0.17” x 0.25”.
Dr. GEJO JOHNS

69. Inmost cases, the wire is not directly ligated into the bracket slots, the anterior wire dimension is adequate to
allow for it.
The bypass, located distal to the lateral incisors, is available in two different lengths to accommodate for
extraction, nonextraction or mixed dentition cases.
Dr. GEJO JOHNS

70. DIMENSIONS OF PREFORMED CONNECTICUT
INTRUSION ARCHES
Maxillary CTA Mandibular CTA
Anterior
dimension
34mm 28mm
Posterior dimension: long (non-
extraction)
22mm 22mm
Posterior dimension: short
(extraction and mixed dentition)
15mm 15mm
Dr. GEJO JOHNS

71. Mechanics
The CTA’s basic mechanism for force delivery is a 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.
Incisor intrusion requires 50g of force directed apically along the center of resistance.
Dr. GEJO JOHNS

72. A pure intrusion arch would have a point contact at the incisors.
Insertion of the wire into the incisor brackets, however, will tend to flare the incisors, which may or may not
be desirable.
The CTA’s point of force application is anterior to the center of resistance, which will flare the incisors.
A tight cinch-back—a sharp bend distal to the molar tube, preventing forward slippage of the wire.
It will prevent incisor flaring during intrusion and produce some retraction of the incisors.
Dr. GEJO JOHNS

73. LINGUAL ARCH FOR INTRUDING AND UPRIGHTING
LOWER INCISORS
W Senior. A lingual arch for intruding and uprighting lower incisors. J Clin Orthod. 2003
Jun;37(6):302-6Dr. GEJO JOHNS

74. This technique was introduced by WINSTON SENIOR.
An .036" lower lingual arch is soldered to first molar bands.
Distal extensions form occlusal rests on the second molars to prevent distal tipping of the first molars as the
incisors are intruded.
Four elastic chains are attached to the anterior bridge of the lingual arch with a mosquito forceps .
Dr. GEJO JOHNS

75. After cementation of the arch, the elastics are stretched to four lingual buttons on the lower incisors . These
should be bonded as far as possible from the gingival margin to facilitate intrusion
Dr. GEJO JOHNS

76. Palatal elastics from TPA
- modification given by Prof. Dr. Jayade Dr. GEJO JOHNS

77. Temporary Anchorage Devices
Dr. GEJO JOHNS

78. Anterior intrusion with TADS
Factors to consider when placing mini-implants includes
1. Sufficient interdental bone
2. Less soft tissue irritation
3. Larger anterior segment
According to Nanda the ideal location for placement of TADS for anterior intrusion is between the
roots of the canine and lateral incisors
The selection of the point of application of intrusive force with respect to Cres of the anterior segment
Dr. GEJO JOHNS

79. The Cres of the six anterior teeth is estimated to be halfway between the Cres of the four incisors and
canine
A light distal force was delivered by an E-chain to the anterior segment to alter the direction of the
intrusive force , so that true intrusion of the anterior teeth could be achieved on their long axis
Dr. GEJO JOHNS

80. BIOMECHANICS FOR MOLAR INTRUSION
Some of the common indications for molar intrusion are
1. Increased anterior facial height
2. To initiate auto-rotation
3. Prosthetic purpose : making space for prosthesis
Increasing the interdental height.
Dr. GEJO JOHNS

81. INTRUSION OF SINGLE MOLAR
• Force should be balanced bucco-lingually and mesio-distally for pure intrusion.
• Line of force should pass through the cres of molar :
• Centre of occlusal table
• Near the furcation area
• Closer to the palatal root of maxillary molar.
• Recommended insertion site of miniscrews :
• Buccal surface – mesial interdental area
• Palatally – distal interdental area Dr. GEJO JOHNS

82. • Additional miniscrews can be placed on either side of the alveolar slope to adjust the
force direction.
• Three or four miniscrews are useful to prevent or correct the tipping of severely extruded
molars.
Three miniscrews Four miniscrews
Dr. GEJO JOHNS Dr. GEJO JOHNS

83. • Insertion site of implant for intrusion of 2 adjacent molars : interproximal buccal and palatal
area
• The cres located below the inter-proximal contact close to the molar *
* Nanda R. Esthetics and Biomechanics in Orthodontics.Elsevier Health Sciences; 2012 May 7.
INTRUSION FOR MOLAR AND ADJACENT TEETH
Dr. GEJO JOHNS

84. INTRUSION OF MOLARS ON BOTH SIDES
Symmetrical intrusion – intrusive force delivered through transpalatal bar connecting both molars
Control of palatal tipping :
1. Expansion of TPA
2. Additional miniscrews on buccal side
Control of mesio-distal tipping ( sagittal direction)
Miniscrew should be inserted on the line connecting the central fossa of both molars Dr. GEJO JOHNS

85. Intrusion of maxillary molars
•Engagement of rigid rectangular wire in buccal side
•Y- Plates are placed at the Zygomatic buttress.
•TPA in the palatal side – to prevent buccal tipping of the posteriors
•Magnitude of intrusive force : 400 g / side Dr. GEJO JOHNS

86. Intrusion of maxillary molars
Simultaneously, archwire is ligated to the miniplates
to intrude/ maintain their exact position for few
months.
When maxillary molars are intruded at the
same level as anteriors , anterior segment is
included with a continuous arch wire .
Dr. GEJO JOHNS

87. Intrusion Of Mandibular Molars
•Anterior open bite with increased mandibular posterior height
•L- plates placed at the molar region of the mandibular body.
•Intrusive force of 400-500 gms/side
•Lingual arch and lingual torque is given in the rectangular wire to prevent buccal flaring Dr. GEJO JOHNS

88. REFERENCES
• Contemporary orthodontics- Proffit
• Orthodontics-current principles and techniques- Graber , Vanarsdall, Vig
• Charles J. Burstone “ Biomechanics of deep overbite correction” semin orthod 2001: 7: 26-33
• Bhavana Shroff, Steven J Lindauer , Charles J Burstone “ Segmented approach to simultaneous intrusion
and space closure: biomechanics of three piece base arch appliance” Am J Orthod dentofac Orthop
1995:107: 136-43.
• Richard J. Smith, Charles J. Burstone, “ Mechanics of tooth movement” vol 85, 294-307
• McNamara JA Jr. Utility arches. J clin orthod 1986;20:p.452-456.
• Martina R. Paduano S. The Translation Arch. J Clin Orthod. 1997;3;11:p.750-753
• Nanda, R. and Uribe, F.A., 2009. Temporary Anchorage Devices in Orthodontics.
• Park Y. Biomechanical Principles in Miniscrew Driven Orthodontics. Temporary Anchorage Devices in
ORTHODONTIC. 2009:317-41. Dr.GEJO JOHNS