9 - Fixed Appliances and innovations in appliances

Question 1

LO

Question 2

The stages in the straight wire appliance treatment are:

Answer 2

• Aligning
• Levelling
• Space closure
• Finishing

Question 3

Don’t need to memorise for BDS

Question 4

Sectioned Mechanics:

Answer 4

• Two archwires
• Bioprogressive
• Rickets
• Burstone t loops

Different to straight wire appliance

Question 5

Andrew’s 6 Keys:

Answer 5

• Molar Relationship
• Tip
• Torque
• Rotation
• Spacing
• Curve of Spee

These are the areas that orthodontic treatment needs to address for successful treatment. It is not always possible to achieve all 6 keys in every patient.

Question 6

Bracket Positioning:

Answer 6

(For straight wire technique, brackets should be placed appropriately)

• Edgewise brackets are placed at determined distance from the occlusal surface.
• Andrews: Midpoint of the long axis of the clinical crown
• FA point
  - Except molars
  - Where is the midpoint? Torque values change with bracket positioning
• MBT: Dougherty gauges

Question 7

Prescriptions

What is this
List 3 main prescriptions
Size of bracket slot can be:

Answer 7

Prescriptions – The bracket slot that is cut in the bracket has different tip torque and rotation. This is known as prescription:
1. Andrews
2. Roth
3. MBT (McLaughlin, Bennet, Trevisi)

Size can be 018 or 022 system

Question 8

What are 1st, 2nd and 3rd order bends?

Answer 8

Movement of the teeth is described as 1st, 2nd and 3rd order bends

1st Order: Movement ‘in/out’ and rotations
2nd Order: Tipping
3rd Order: Torque

Question 9

Torque - expression ‘slop’

Answer 9

When you use wires that go in the bracket slots, the wires increase throughout the treatment.

Throughout treatment, as there is less and less space between the wire and the bracket slots, a phenomenon called slop occurs, where the bracket does not fill the prescription, therefore it will not express the prescription fully

CHAGPT explanation:
- Slop occurs when the wire is smaller than the bracket slot, leaving extra space.
- This prevents the bracket from fully expressing its built-in prescription for tip, torque, and rotation.
- As wires get thicker, slop decreases, and the teeth move closer to the ideal positions.

Question 10

Stages of straight wire appliances - Aligning

1- How are labial and buccal segments aligned?
2- How is de rotation or over rotation managed?
3- How are upper incisors in crossbite with lower incisors managed?

Answer 10

1-
• Labial & buccal segments
– include all teeth initially
– create space first, then include working AW push-coil, ‘pull’ mechanics

2-
• De-rotation/Over-rotation
– Undertie, Overtie, lingual cleats/buttons
– Steiner Wedges, Rotation Wedge

3-
• Upper incisor(s) in x-bite with LLS:
– if bracket in the way, debond and reposition
– ‘back to front’ power chain

Question 11

Wires: Alignment

What type of wires are used in fixed appliances for alignment:

Answer 11

1-

Formable wires:
- Looped wires
- Multi-strand wires - Braided, Coaxial or Three strand twist
- NiTi (Variable force)

Some have Perfect shape memory – Impossible to permanently deform the wire using orthodontic
forces:
- Thermally active NiTi wires
- CuNiTi

Question 12

Question 13

Rotations

What can be used to de rotate teeth?

Answer 13

• Undertie
• Steiner Wedge
• Rotation Wedge

Question 14

For rotations

Question 15

Vertical control: Bite opening

Answer 15

If patient has a deep bite, need to open bite:

• Temporary
• Sectional
• Levelling in the continuous arch
• Elastics

Question 16

Upper Teeth in Crossbite with the Lower Arch

What could happen?
What is the solution?

Answer 16

• Bracket of tooth in crossbite might be bitten off therefore posterior bite opening

• Solution: Back to front power chain

Pt left premolar in cross bite and right lateral incisor is in cross bite - so can put bracket on inside of the incisor and an elastomeric chain

Question 17

What can you see here?

Answer 17

Mixture of fixed and removable appliance

Can see Southend clasps - on upper incisors

But also fixed to align the canines - has been surgically exposed and pulled down by power arm

Question 18

What is this
What is it used for

Answer 18

Bite turbos

Used to open deep bites - Bite opening

Question 19

What is this and its use?

Answer 19

Secondary arch wires
Very thick upper wire on top of the standard wire - can be used to expand or contract

Question 20

What’s this and use?

Answer 20

Rapid maxillary expander

Opens the bite
Screw turned a few times a day so mid palatal suture opened and rapid expansion is achieved in a few weeks

Question 21

Bite opening: as sectional technique

Answer 21

He said just to list not memorise?

Question 22

What’s this?

Answer 22

Secondary arch wire - this case is maxillary arch wire used to open bites

Question 23

Brackets usually placed?

Answer 23

Middle of the tooth
But sometimes may be placed elsewhere eg more incisally on front teeth and more gingival on back teeth can lead to bite opening

Question 24

What’s this

Answer 24

elastic
This is class II elastics- pull upper anterior segment back and push lower posterior segment forward
Can also be sued to treat vertical discrepancy

Question 25

Wires: Space Closure What wire is used to: Move single teeth along an arch wire Space closure and over bite control

Answer 25

Question 26

Space closure: Anchorage, Friction and Frictionless mechanics

Answer 26

Single tooth and blocks of teeth can supply anchorage Single root and smaller roots provide less anchorage than multirooted teeth.

Question 27

What can you see

Answer 27

Question 28

If friction is too great to move segments of teeth for space closure what can be used?

Answer 28

Looped mechanics

Question 29

Friction vs frictionless mechanics - for understanding Unsure if correct- answer is from CHATGPT

Answer 29

In friction mechanics, the tooth moves by sliding along the archwire, creating friction between the wire and the bracket slot or ligature - eg elastics, power chains In frictionless mechanics, there is minimal or no contact between the archwire and bracket during tooth movement, eliminating frictional resistance. • Commonly achieved using loops

Question 30

Finishing

Answer 30

- First order – Rotation/in out - Second – Angulation/tip - Third order – Torque - Vertical – Occlusion - Tooth size and shape

Question 31

Wires used in Finishing:

Answer 31

Could be any below used in an appropriate way

Question 32

Patient at finishing stage - 6 keys have been achieved

Question 33

No spaces No rotations Good tip/ torque and buccal segment relationship 6 keys

Question 34

For improved aesthetics for fixed what can be used?

Answer 34

- Conventional appliances: Improved Aesthetics - Ceramic or composite brackets - Self ligation

Question 35

Overview of orthodontic techniques

Answer 35

- removable - Fixed: 1. Labial - Tip/torque/ rotational/ vertical control - standard edgewise - SW (sectional/ segmental) - Begg - Tip - Edge 2. Lingual - mixed

Question 36

CAD/CAM in Orthodontic Treatment – Simulated Tooth Movement:

Answer 36

- Aligners - Lingual Appliances – Individualised bracket design and indirect bonding

Question 37

Aligners steps What do you need to provide aligners

Answer 37

- Impression (Scan) - Treatment Plan Submission - Postage (Documents) - Clinical Check - Fitting - Attachments - Speech impact? Need: Courses for ‘registration’ and teaching Forms and advices Add set photos and radiographs 0.25mm movement per aligner Question on how effective they are on Torque, Intrusion, Extrusion, and Bodily Movement - may not be suitable for complex

Question 38

Example of pt eligible for aligners Normal occlusoin with good interdigtated class 1 buccal segment relationship LHS, RHS slightly post normal with some irregularity affecting both upper and lower arches Click answer

Answer 38

Question 39

Lingual fixed appliances List the types: List 6 disadvantages

Answer 39

1- - Prefabricated - Wire bending - Individualised - Acrylic interface - Thin (wire bending) - Thick (predetermines wire shape) - Individually cast (CAD/CAM) 2- - Preop costs - Special pliers - Speech problems - Lingual ulcers - Failure rate - Difficulty with repairs

Question 40

Lingual fixed - bonding technique

Answer 40

Bonding technique - indirect Repairs challenging Specific materials needed

Question 41

Lingual fixed Lingual attachments mechanics:

Answer 41

Question 42

Lingual Fixed List 4 issues with individualised lingual fixed:

Answer 42

- cost - upfront charge to operator - chair side time - setup Unsure make slide below part of Q?

Question 43

Prefabricated lingual appliances on the left Individualised lingual appliance on right - smaller than prefabricated

Question 44

Simple treatment : directt lingual

Answer 44

Apply fixed appliance directly with plier For understanding prev FC required lab and CADcam