connecticut intrusion arch (cia)

Connecticut Intrusion Arch (CIA)

Supervisor: Prof. Maher FoudaPrepared by: Nader A. Giacaman

Nanda, R.: The differential diagnosis and treatment of excessive overbite, Dent. Clin. N. Am. 25:69-84, 1981.

Lindauer, S.J.: Orthodontic treatment planning, in Biomechanics in Clinical Orthodontics, ed. R. Nanda, W.B. Saunders Co., Philadelphia, 1997, pp. 23-49.

Numerous methods have been described for incisor intrusion, Begg, Ricketts, and Burstone

employ the same basic principle:

Romeo, D.A. Burstone, C.J.: Tipback mechanics, Am. J,. Orthod. 72:414-421, 1977.

Davidovitch, Moshe, and Joe Rebellato. "Two-couple orthodontic appliance systems utility arches: a two-couple intrusion arch." Seminars in orthodontics. Vol. 1. No. 1. WB

Saunders, 1995.

Nanda, Ravindra, Robert Marzban, and Andrew Kuhlberg. "The Connecticut intrusion arch." Journal of clinical orthodontics: JCO 32.12 (1998): 708.

Tipback bends at the molars to provide an intrusive force at the incisors.

Nanda archBurstone arch Utility arch by Ricketts

The wire materials used for intrusion in these techniques are diverse, but all recognize the

need for a light, continuous force.

Nickel titanium alloys are currently the materials of choice for delivering light,

continuous forces under large activations.

These alloys have high memory and low load- deflection rates, producing small increments of deactivation over time

and thus reducing the number of reactivation appointments.

Burstone, C.J.: variable-modulus orthodontics, Am.J. Orthod. 80:1-16,1981.

Kusy, R.P.: A review of contemporary archwires: Their properties and characteristics, Angle Orthod. 67:197-208, 1997.

CIA is a multi-functional wire that was developed by Dr. Ravindra Nanda.This versatile wire can be used for:1. Incisor Intrusion.2. Simultaneous Class ΙΙ Molar Correction.3. Incisor Flaring.4. Correction of Minor Open Bite (Incisor Extrusion).5. Correction of Anterior Occlusal Cant.6. Preventing the side effects associated with

canine retraction.

Connecticut Intrusion Arch (CIA)


Esthetics and biomechanics in orthodontics, second edition, Ravindra Nanda.

CIA(Connecticut Intrusion

Archwire) CNA™ Beta ΙΙΙ Titanium

ArchwireCTA™ Nitanium Super Elastic

Archwire

Appliance Design

Two wire sizes are available: .016 × .022 and .017 × .025

(for both CNA and CTA)

CTA™ Nitanium Super Elastic Archwire is fabricated from a nickel titanium alloy to

provide the advantages of shape memory, spring back, and light, continuous force

distribution. Additionally, low forces help to minimize root resorption.

Two wire sizes are available: .016 × .022 and .017 × .025.


The maxillary and mandibular versions have anterior dimensions of 34mm and 28mm, respectively. Although

in most cases the wire is not directly ligated into the bracket slots, that’s why all the anterior wire dimension is adequate for all cases. The bypass, located distal to

the lateral incisors (posterior dimensions), is available in two different lengths to accommodate for extraction,

nonextraction, and mixed dentition cases.


OrthoOrganizers Catalog

For example

CNA™ Beta III Titanium Archwire version delivers higher forces and accepts permanent bends.

Bending allows force adjustment and cinch back. Two wire sizes are available: .016 × .022 and .017 × .025.


The maxillary and mandibular versions have anterior dimensions of 34mm and 28mm, respectively. Although in most cases the wire is not directly ligated into the bracket slots, that’s why all the anterior wire dimension is adequate for all cases. The bypass, located distal to the lateral incisors (posterior dimensions), is available in one length (Long).


• 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 tubes.

• When the arch is activated, a reciprocal action of the intrusion arch on the molars or the buccal segments is the extrusion and/or distal tip back of the crowns and the mesial movement of the roots.

Mechanics

The intrusion arch is activated by:

1- Placing a 30-degree gingival bend 2- to 3-mm mesial

to the molar tubes so that the wire lies passively in the

vestibular sulcus.

2- Activation is accomplished by bringing it occlusal and

tying it to the anterior segment as a point contact.

30˚

• The intrusion arch can also be tied back or cinched to prevent flaring of the incisors if the intrusive force is being applied anterior to the center of resistance (CRES) of the incisors.

• As a general guideline, 10 to 15 g of force per incisor is acceptable to prevent posterior side effects. Recent evidence has shown that the intrusive forces can be made so light that reactive forces on the anchor teeth remain well below the force levels needed for extrusion and tipping. Therefore the use of a headgear to prevent side effects is completely avoidable.

Steevenbergen EV, Burstone CJ, Prahl-Andersen B, Aartman IHA. The influence of force magnitude on intrusion of the maxillary segment. Angle Orthod. 2005;75:723–729.

On average, after the initial activation period of 3 to 4 weeks the base arch should intrude 0.4-

to 0.6-mm per month.Faber ZT. The Relationship of Tooth Movement to Measured Force Systems: A Prospective Analysis of the Treatment Effects of Orthodontic Intrusion Arches

[master’s thesis]. Storrs, CT: Division of Orthodontics, University of Connecticut; 1994.


About 1mm of intrusion can be expected every six weeks.

Incisor Intrusion


A Case with Class ΙΙ molar relationship, Deep Bite (Upper

incisors intrusion is needed)


A. Patient requiring intrusion of maxillary incisors, treated without extractions.

B. CTA tied to anterior segment only at lateral incisors because of incisor protrusion. If incisors had been

retroclined, CTA would have been ligated between central incisors, because the CTA’s point of force application is anterior to the center of resistance, which will flare the

incisors even more.Cinch-backs distal to molars maintain anteroposterior

incisor positions.

C. As molars tip back to Class Ι relationship, spaces are created in premolar regions. (Favorable in Class ΙΙ molar

relationship, to achieve Class Ι)To prevent opening of spaces in Class Ι molar patients

(minimize tipback side effect):1- Premolars are tied to molars in a posterior wire segments

and/or2- Use transpalatal bar/ Lingual arch.

D. Patient after treatment, showing overbite correction and Class Ι buccal occlusion.

A Case with Class Ι molar relationship, Deep Bite (Lower

incisors intrusion is needed)


A. Patient with deep overbite before treatment. Upper-lip-to-upper-incisor relationship was ideal; therefore, mandibular

incisor intrusion was required.

B. Mandibular CTA in place, with wire segments in posterior brackets to maintain Class Ι molar relationship by preventing

molar tipback.

C. Patient after treatment, showing correction of deep overbite and maintenance of Class Ι buccal occlusion.

Another Case with Class Ι molar

relationship, Deep Bite (Lower incisors

intrusion is needed)


A–C, This adolescent female patient had the chief complaint of excessive overbite. On careful analysis it was observed that her upper incisor exposure was adequate both at rest and during smiling. D–F, The decision was made to intrude the lower incisors only so the deep bite malocclusion could be resolved without significantly affecting the patient’s smile esthetics. Segmental intrusion of the lower incisors was carried out with an overlay intrusion arch. G–I, Treatment results.

The following flow chart shows how the CTA is used to obtain

incisor intrusion:

1. Insert a section of wire into the incisor brackets.

2. Choose the appropriate CTA (Long for nonextraction or Short for extraction or mixed dentition).

3. Try in the CTA to determine the proper length.

4. Cut off the excess wire protruding from the molar tubes leaving 3mm per side for cinch- back bends.

5. Insert the posterior legs directly into the molar auxiliary tubes.

6. Tie the CTA to the anterior segment at the lateral incisors or between the central incisors.

Tips!!!

(A )Estimated location of the CRE S of themandibular incisor segment in the sagittal

plane.(B ) Estimated location of the CRE S of the

mandibular incisor segment in the transverse plane.Davidovitch, Moshe, and Joe Rebellato. "Two-couple orthodontic appliance systems

utility arches: a two-couple intrusion arch." Seminars in orthodontics. Vol. 1. No. 1. WB Saunders, 1995.

When all four incisors need to be intruded with

maintenance of axial inclination (without moment production), intrusive force must be applied near the distal surface of lateral

incisors.

In order to produce intrusion and buccal tipping

of incisors, force must be mesially applied to lateral

incisors,

whereas for intrusion with retroclination, load must be distally applied to canines.

Santos-Pinto also suggests other points of force

application, which vary between pure intrusion and

intrusion associated with buccal tipping or

retroclination.

Vanden Bulcke MM, Burstone CJ, Sachdeva RC, Dermaut LR. Location

of the centers of resistance for anterior teeth during retraction using

the laser reflection technique. Am J Orthod Dentofacial Orthop.

1987;91(5):375-84.

Santos-Pinto A. Pergunte a um Expert. Rev Clin Ortod Dental Press. 2004;3(4):8-19.

Different points of force application and mechanical effects on incisors:1, 2 and 3 = intrusion + buccal inclination; 4 = intrusion; 5 = intrusion + retroclination.

Simultaneous Class ΙΙ Molar Correction


The CTA is ideally suited for simultaneous intrusion and Class ΙΙ molar correction.

The V-bend mesial to the molars corrects a Class ΙΙ molar relationship by tipping the molars

distally. This tipback effect can be maximized if

posterior anchorage is reduced.

If no incisor intrusion is desired, the anterior anchorage group can be enlarged by extending

the anterior section of wire to the canines.

Incisor Flaring


In patients with upright or lingually inclined incisors, the CTA can be used to flare

the incisors without any side effects on adjacent teeth. If the CTA is not cinched back,

it will slide forward through the molar tube, and the incisors will flare the incisors even

more.

The following flow chart shows how the CTA is used to

obtain incisor flaring:

1. Choose a CTA with the V-bends mesial to the molar tubes.

2. Insert the posterior legs directly into the molar tubes, and cut off the excess wire.

3. Increase posterior anchorage if molar tip-forward is not desired.

4. For maximum flaring, tie the CTA directly into the incisor brackets.

Correction of Minor Open Bite (Incisor

Extrusion)


The reverse configuration of the intrusion arch as an extrusion arch is an obvious application that is not commonly used

partly because of side effects on the molars.

(A) When the CTA is inserted upside down, the anterior portion of the wire lies occlusal to the incisors. This will extrude the incisors while creating a mesial tipping moment and

an intrusive force at the molars.

The molar intrusive force is desirable, but rarely clinically significant. The mesial

tipping is usually undesirable, since it may worsen an open bite. To counteract this side effect, a high-pull headgear can be used, or the premolars can be incorporated into the

posterior segment to prevent forward tipping of molars and augment intrusive

force of CTA on molars. (B,C)

The following flow chart shows how the CTA is used to obtain

incisor extrusion:

1. Insert a section of wire into the incisor brackets.

2. Choose the appropriate CTA (Long for nonextraction or Short for extraction or mixed dentition).

3. Increase posterior anchorage if molar tip-forward is not desired.

4. Try in the CTA to determination the proper length.

5. Cut off the excess wire protruding from the molar tubes.

6. Insert the CTA upside down, with the apex of the V-bend pointing gingivally and the posterior legs entering directly into the molar tubes or molar auxiliary tubes.

7. Tie the CTA incisal to the anterior segment.

Correction of Anterior Occlusal Cant


In planning for the correction of anterior occlusal cants, the offending teeth must

first be identified, and then the mode of correction-

intrusion or extrusion – must be selected.

For example (A,B,C) if only two incisors were

supererupted and needed to be intruded, it would not be

necessary to tie all four incisors to the CTA; only the

offending teeth would be tied to the CTA using

asymmetrical ligation.

The following flow chart shows how the CTA is used to obtain Correction of Anterior Occlusal

Cant:1. Determine the appropriate vertical incisor

position, and decide which incisors need intrusion or extrusion.

2. Add a transpalatal bar if molar side effects are not desired.

3. Choose a CTA with the V-bends mesial to the molar tubes.

4. Try in the CTA to determine the proper length.5. Cut off the excess wire protruding from the

molar tubes.6. For incisor extrusion,, place the CTA with the

V-bend pointing gingivally. For incisor intrusion, place the CTA with V-bend pointing incisally.

7. Insert the posterior legs directly into the molar tubes or molar auxiliary tubes.

8. Tie the CTA only to the brackets of the incisors to be leveled.

9. For correction of an anterior cant, use a 2-2 wire segment, and tie the CTA only to the side to be corrected.

Preventing the side effects associated with

canine retraction


A popular method of canine retraction is “frictional mechanics” employing a

continuous arch system. The obvious advantages of this system (compared to

frictionless mechanics) are reduced possibility of unpredicted canine movement (e.g., rotation, flaring, and extrusion of the

canine) and minimal wire bending. However, when an archwire with a low load-deflection rate is used it tends to deform, leading to undesirable side effects on the anterior

teeth in the form of extrusion of the incisors or deepening of the bite.Nanda RS, Ghosh J. Biomechanical considerations ion sliding mechanics. In: Nanda R, ed.

Biomechanics in Clinical Orthodontics. Philadelphia, PA: WB Saunders; 1997:188–217.

This type of deep bite can also be termed “iatrogenic deep bite,” which in the present

context means deep bite induced inadvertently by the clinician. With larger or

rigid archwires the system might develop excessive friction leading to delayed tooth movement, anchorage loss, or maybe even

cessation of canine retraction.

Development of deep bite (iatrogenic) during canine retraction (sliding mechanics) due to occlusal

deflection of the archwire.

Therefore the use of a

0.016 × 0.022-inch CTA as an

overlay archwire to optimize the biomechanical

system for canine

retraction, is recommended.

A, Application of Connecticut Intrusion Archwire (CTA) to prevent deepening of the bite and simultaneously to augment

anchorage during canine retraction. B–D, Clinical views demonstrating the application described in A.

The clockwise moment and the intrusive force on the incisors that generates from CTA intrusion arch (if

tied anterior to the CRES of the anterior teeth) ensure the stability of the incisors by counteracting

the iatrogenic forces generated by canine retraction.

Canine retraction: extrusion of the incisors + counterclockwise moment

CTA: Intrusion of the incisors + clockwise moment

• The CTA Connecticut Intrusion Arch is a multifunctional wire that is preformed from nickel titanium and provides the high performance and mechanical advantages of these alloys. Although incisor intrusion is its most common application, various other functions can easily be performed with only minor modifications.

• The CTA will remain active at a constant force level for a long period of time, allowing long intervals between appointments. Its simplicity of design and minimal requirement for auxiliary hardware make it an ideal addition to the armamentarium of the busy clinician.

Conclusion

connecticut intrusion arch (cia)

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