FIXED APPLIANCES

DEFINITION

Fixed Appliances are devices or equipments that are attached to the teeth , cannot be removed by the patient and are capable of causing tooth movement.

INDICATIONSFixed Appliances are indicated when precise tooth movements are required

Correction of mild to moderate skeletal discrepancies

Correction of rotation

Overbite reduction by intrusion of incisors

Multiple tooth movements required in one arch

Active closure of spaces: extraction spaces/hypodontia

Intrusion/ Extrusion of teeh

COMPONENTS OF FIXED APPLIANCES

Components of fixed appliances

Active components

Seperators

metal elastic

Arch wires Elastics Springs

Passive components

Brackets Bands Accessories

LockpinsLigiature

wire modules

Molar tube

SEPARTORS

Seperators are used to create space for banding teeth

Tight proximal contacts does not allow proper banding of teeth

PRINCIPLE: It is a device to wedge the teeth in

place B/w the teeth

TYPES Metal seperatorsElastic seperators

ARCHWIRES

• Ideal Properties Springback Stiffness Formability Resilience Biocompatibilty Joinability Frictional characteristics

Materials

• Stainless steel/ Cobalt chromium• Precious metal• Nickel-Titanium• Beta-Titanium• Composite Plastics

BANDS

Bands are thin strips of stainless steel which are adapted to the contours of the tooth to which attachments are welded or soldered

TYPES : 1. Preformed 2. Custom made

1. Molar Bands 2.Premolars 3.Incisors

BRACKETSThe force required for orthodontic tooth movement is transmitted from the active components through the bracket.

MOLAR TUBEAccessory Archwire

Slot

Main Archwire Slot

Headgear tube

HOW TO ATTACH A FIXED APPLIANCE TO THE

TOOTH????

BANDS FOR ATTACHMENTS.

BONDED ATTACHMENTS.

Indications for Banding

• Teeth that will receive heavy intermittent forces against the attachments.

• Teeth that will require both labial and lingual attachments.

• Teeth with short clinical crowns.

• Teeth with extensive restorations.

STEPS IN BANDING1.SEPERATION

2.FITTING BANDS

3. CEMENTATION

BONDED ATTACHMENTS• Mechanical locking of an adhesive to irregularities in

the enamel surface of the tooth and to mechanical locks formed in base of the 0rthodontic attachment.

COMPONENTS OF THE SYSTEM :1. Tooth surface and its preperation.

2. The design of the attachment base.

3. Bonding material itself

Armamentarium

Direct Bonding

1. Cleaning

2.Acid etching

3.A small amount of bonding agent is squeezed into the mesh on the back of the bracket , and it is pressed to place on the tooth surface.

4.Excess bonded material is removed from around the bracket

6.The bracket is bonded in place.

5.For light cured materials, a cordless light is used to activate the adhesive bonding process

Indirect Bonding1.Brackets are placed precisely on a cast of the teeth and held in place with a fitted resin

2.After the brackets are cured in the ideal position, a transfer tray is formed and placed on the working cast.

3 The trays are removed from the working cast after soaking in warm water and trimmed.

4. The teeth are isolated , etched, and a chemically cured twopaste resin is painted on the etched enamel and brackets.

5. After the resin has completely set , the trays are carefully removed , leaving the brackets bonded to the teeth.

ACCURACY IN PLACEMENT!

Debanding/Debonding

Bonded attachements are almost always preferred for anterior teeth and premolars .

Bands usually are preferred for first molars , especially if both buccal and lingual attachments are needed.

Second molars are bonded if exposure of crown allows it , banded if not.

There is an increasing trend towards bonded attachments on all the teeth ,however, especially in older patients who have longer clinical crown and tighter contacts .

RULES!!!!!!

THE DEVELOPMENT OF CONTEMPORARY FIXED APPLIANCES

E-Arch (Angles first appliance)

Pin and tube appliance

Edge wise appliance by Angle Ribbon arch appliance by Angle

Modified Ribbon arch by Raymond begg

Preadjusted edgewise appliance by lawrence Andrews

Tip edge appliances by peter Kesling

ANGLE’S PROGRESSION TO

EDGEWISE

E-Arch Pin and tube Ribbon Arch Edgewise

Only heavy interrupted forces Only tipping movements achieved Unable to precisely position any individual

tooth

Overcome the drawbacks of E-Arch Incredible degree of craftsmanship was involved in

constructing and adjusting the pin and tube appliance

Impractical clinically Only Angle’s and one of his students ever

mastered this appliance Heavy base arch meant that the spring qualities

were poor Many small adjustments needed

Archwire was small enough to have good spring qualities and efficiently aligned malposed teeth

Major weakness of the appliance was that it provided relatively poor control of root position

Resiliency of the ribbon archwire did not allow generation of moments necessary to torque roots to a new position

Incisogingival and buccolingual tooth movements were possible but mesiodistal tooth movements could not be achieved

Ability to move teeth in all 3 planes of space Good control over tooth movement Bodily movement possible Precise finishing possible

1.E-Arch

2.Pin and Tube

3.Ribbon Arch

4.Edgewise

Bends

1st order 2nd order 3rd order

Disadvantages of Angle’s edgewise appliance • Heavy forces required Complex

wire bending

• Increased friction

• Extraoral forces for anchorage required

• Difficulty in opening deep bites

TWEED’S MODIFICATION OF EDGEWISE

• Advocated extraction of teeth in selected casesfor better stability

• Tweed moved the teeth bodily and used the subdivision approach for anchorage control, first sliding the canines distally the arch wire and then retracting the incisors

BEGG’S APPLIANCE

• Modified ribbon arch technique and introduced the Begg’s light wire differential force technique

• Concluded extraction of teeth wasnecessary and set out to adapt ribbon arch appliance so that itcould be used for better root positioning control.

• Begg’s adaptation took 3 forms:

1. Replaced precious metal wire with high strength 16 mil stainless steel

2. Retained the original ribbon arch bracket but turned it upside down so that the bracket slot pointed gingivally rather than occlusally

3. He added auxillary springs to the appliance for the control of root position• Resulting in reduced friction as the area of contact between the narrow ribbon

arch bracket and the archwire was very small and the force of the wire was also small

• Begg’s strategy for anchorage control was tipping/uprighting

LABIOLINGUAL, TWIN WIRE

• First half of the 20th century, Labiolingual appliance & Twinwire appliance were major competing appliances for repositioning teeth

• Bands on first molars and a combination of heavy lingual and labial archwires to which fingersprings were soldered to move individual teeth Labiolingual appliance

• Twin wire appliance used bands on incisors as well as molars and featured twin 10mil steel archwires for alignment of the incisor teeth.

• Delicate wires were protected with long tubes that extended forward from the molars to the vicinity of canines.

• None of these appliances were capable of more than tipping

CONTEMPORARY EDGEWISE• Major steps in evolution of edgewise include :

Automatic rotational control

Alteration in Bracket Slot Dimensions

Straight Wire Prescriptions

EDGEWISE TECHNIQUE IN WIRE BENDING

PURPOSE COMPENSATION

First Order/In and Out bends To compensate for difference in thickness of labial surfaces of individual

teeth

Compensated by built-in variation in thickness of bracket base

Second Order/ Tip back bends Required for mesiodistal root positioning

Compensated by angulating bracket base or bracket slot

Third Order/ Torque bends Required to compensate for the difference in inclination of facial surface

to the true vertical

Bracket slots are inclined to preadjusted appliances to compensate for third order

bends

Bends

1st order 2nd order 3rd order

SELF LIGATING BRACKETS

‘’A bracket which utilizes a permanently installed , movable component to entrap the arch wire.’’

INDIVIDUALLY CUSTOMIZED BRACKETS Offer the prospect of eliminating almost

all archwire wire bending.

3D scan is taken of a dental cast

The information is used to precisely cut each bracket using CAD/CAM technology , so that slot for each bracket has the appropriate thickness, inclination and torque needed for ideal positioning of the tooth and archwires with an arch form established for that patient are supplied.

ARCH FORM AND ARCH WIRE FABRICATION

WIRE BENDING ROBOTS

ANY QUESTIONS???