Fixed Appliances Flashcards
What is a Fixed Appliance?
An Orthodontic appliance which is fixed to the teeth and cannot be removed by the pt
What movements are created by a fixed appliance?
- Tipping
- Bodily
- Torque
- Extrusion
- Intrusion
- Rotation
Indications for Fixed Appliances
*mild/moderate skeletal discrepances
* Intrusion/extrusions
* corrections of rotations
* Overbite reduction
* Multiple tooth movements
* Space closure
* Psychological well being
Advantages for Fixed Appliances
- AP, Transverse and verticle movements
*Bodily Movement
*complex maloclussions
*space closure - Multiple tooth movements
Upper and lower arches - intrusion/extrusion
*overbite reduction
Disadvantages for Fixed Appliances
- High Anchorage demands
*OH - Increased Chairside
*Ulcers
*Breakages - Root Resorption
*not very aesthetically pleasing
Describe Mode of Action
Forces applied to the teeth by a fixed appliance
Describe Force Couple
Magnitude of force applied to tooth x Distance between them
Components of a Fixed Appliance
- Bands
- Brackets
- Archwires
- Auxilaries
What are Bands made of and where are they usually placed?
Stainless Steel
Premolars and Molars
S
oldered to the applaince
What appliances are bands used for?
- Fixed applainces
- Headgear
*TPA
*RME
*Quadhelix
*Lingual arches
When are bands used?
- Failure with bonding Eg. Crowns and large restorations
- Restricted access
- mositure control
- when used with an applaince for anchorage
What are bands cemented with?
GIC (Bandlock PolyF Zinc Phosphate)
* Adhers to enamel
*fluoride releasing
*sets with contact to saliva
*indent always placed buccally
Advantages of Bands
- Less chance of debonding
*more stable - canbe used for an additional attachment EG.TPA
Disadvantage of Bands
*Seperation needed
*less aesthetic
*irritaion to gingivae
*Slower to bond than brackets
* More appointments
*Expensive
*Gaps after debond
What is the function of a Bracket?
Spreads and contrls forces that are applied from the archwires and auxiliaries
Where can brackets be bonded?
Enamel surface of the crown:
Labial - buccal fixed
palatal/lingual surface - ligual applainces
Names the three types of Brackets
- Edgewise
- Ribbonwise
3.Self ligating
Name the two types of Edgewise Brackets
- Standard - no prescription
- Preadjusted - prescription in the bracket
- Tip edge - prescription in the bracket
Name the two sizes of Edgewise brackets
- 0.018in x 0.025
- 0.022 x 0.028
Edgewise Characteristics
- Single archwire and 4 tiewings
*reduced interbracket span
*width increased- control of rotations and tooth width
*elastomeric modules used
Advantages of Edgewise Brackets
- available both standard and preadjusted
*preadjusted - reduce the need of wire bending
*good sliding mechanisms
*good finishing
Disadvantage of Edgewise Brackets
- ignore biological variation
- produces friction + more anchorage needed
- can create poor OH with elastomeric modules
*modules = more chairside
What is a working wire for a 0.018 x 0.025 Edgewise bracket
16x22 SS
What is a workig wire for a 0.022 x0.028
19x25 SS
Name the three most common Preadjusted Edgewise appliances
- Andrews
2.Roth
3.MBT Mclaughlin, Bennet, Trevisi (highest Torque)
What Bracket type needs wire bends?
Standard Edgewise
Name the Three wire bends
- First order bend
- second order bend
3.Third order bend
First Order Bend
- IN/OUT movements
- Corrects tooth widths
*Bucco - lingual - labial - Palatal
*AP movements
Second Order Bend
- TIP movements
- corrects angulation
- bends in the vertical plane to create mesiodistal angulation
Third Order Bend
*Torque Movements
* Rectangle Wires
*palatal and buccally root torque by archwire being twisted forwards
Narrow Brackets =
*larger bracket interspan
* archwire= more flexible
* Faster alignment
Wider Brackets =
*Less bracket Interspan
* used for derotation and mesiodistal control of the teeth
What is a Begg Appliance?
Light wire and light force Appliance
List the components of a Begg Appliance
- Brackets
*Pin
*Archwire
What are the advantages of a Begg Appliance?
- overcomes high anchorage demands - light anchorage appliance
What wires does a Begg Appliance use?
Round wires only which loosely fit into the bracket = alot of slop
In a Begg Appliance what is used to hold the archwire in?
Pin
What auxiliaries are used to create tooth movements for Begg Appliances
- Inter maxillary Elastics - tips teeth
- springs and loops - Upright the roots + rotational movements
Name the features of a Tip Edge Appliance
- Round wires and light forces
- detailed finishing - each bracket has a built in prescription
Name the three stages of the Tip Edge Appliance
- Align Teeth
- Start Space closure
- Incline teeth
Describe the bracket of an Self Ligating Appliance
Door/clip which ensures full engangment and holds the archwire
Name the two types of Self Ligating Appliances
- Passive
2.Active
Describe an Active Self Ligating Appliance
Active forces on the wire
Describe an Passive Self Ligating Appliance
Slide mechanisms - passive and places no active force on the archwire
Advantages of Self Ligating Appliances
- Arch circumference increased= wider smiles
*reduced chairside
*Different torques available
*Produce lower friction
*improved OH due to no modules - longer time inbetween appts
Advantages of Buccal Appliances
- Good access
- good finishing and detail
- can now get aesthetic brackets
- quicker than lingual
Disadvantages of Buccal Appliances
- visible
*Decalcification - Aesthetic brackets can fracture
What are the brackets called which are used for Lingual Appliances
Preadjusted Ribbonwise brackets
How are Lingual Brackets different?
They are thicker vertically than horizontally
What are the components of a Lingual Appliance?
- Custom brackets/wires
*indirect bonding - in a jig
Advantages of Lingual Appliances
*Aesthetically pleasing
* less decalcification
* good fro treating overbites as they can act as a bite plane
* indirect bonding with a jig - correct position
Disadvantages of Lingual Appliances
- Speech
*Ulcers - demanding on clinician
- reduced interbracket span
*finishing difficult
*cost - if lost a new bracket needs to be ordered
List Bracket materials
1.Metal
2.Stainless Steel
3. Cobalt - chromium
4. Titanium
5. Ceramic
6. Plastic
List the two materials of Aesthetic brackets
- Plastic
2.Ceramic
List the plastic material used for Aesthetic brackets
*Polyurethane
*polycarbonate reinforced ceramic
*Fiberglass fillers
List the Ceramic material used for Aesthetic brackets
Aluminium oxide either:
1.opaque - Polycrystalline
2.Clear - Monocrystaline
Advantages of Ceramic Brackets
- Visually pleasing
*popular with patients - Better than plastic
Disadvantages of Ceramic Brackets
- Brittle/fracture
- Cause wear on opposing teeth
- enamel fracturing @debond
- increase of friction ( now brackets have a metal slot to prevent)
- expensive
- poor tie wings
List the two ways Brackets are manufactured
- Spot Welded
- Injection Moulded
Describe a spot welded bracket
*Base and bracket separately stuck together
* cheaper and can debond from each other
Describe a Injection moulded bracket
- base and bracket injection moulded together
- Expensive
List the two ways a bracket is bonded
- Direct bonding
- Indirect bonding
What is Direct bonding?
When a bracket is placed individually
What is Indirect bonding?
when a bracket is placed in a positioning tray EG. lingual appliances
Name the two bonding methods
- Mechanical bonding/interlock
- Chemical Bond
What is Mechanical Bonding
- interlocking of molecules
*Phospheric acid applied to the tooth surface - washed and dried
- exposed cystalline structures within the enamel
*allows bond to flow and is increased by mesh base on the bracket
What is Chemical Bond
- Composite and primer
- allows polymerization
( 2 molecules join and share anatomical structures)
