URA Appliance Design

Question 1

What components make up an appliance design?

Answer 1

ARAB
Aim
Active component
Retentive component
Anchorage
Baseplate

Question 2

What is an active component?

Answer 2

Any component that moves teeth through the application of force (1mm per month)

Question 3

List examples of active components

Answer 3

Finger spring + guard
Z spring
Flapper spring
T spring
Buccal canine retractor
Roberts retractor

Question 4

What is a retentive component?

Answer 4

Resistance to displacement forces (that can dislodge appliance)

Question 5

Examples of retentive components

Answer 5

Adams clasps
Southend clasps
Labial bows

Question 6

Name the 5 main intraoral forces

Answer 6

Tongue
Gravity
Mastication
Speech
Active component

Question 7

What is anchorage?

Answer 7

Resistance to unwanted tooth movement

Question 8

What is the anchorage component?

Answer 8

Baseplate

Question 9

Function of a baseplate

Answer 9

Anchorage - disspates forces
Provides an oral seal (adhesion+ cohesion) and joins all components

Question 10

2 types of cure for a baseplate

Answer 10

Self cure
- Used mostly

Heat cure
- controlled curing
- No residual monomer
- Less shrinkage
- Stronger

Question 11

Gauges of wire for retentive components

Answer 11

Adams
Southend
Labial
ALL 0.7mm HSSW
0.6mm for deciduous

Question 12

Gauges of wire for active components

Answer 12

Finger springs + guard
Z springs
Flapper spring
T spring
ALL 0.5mm HSSW

Buccal canine retractors
Roberts retractors
BOTH 0.5mm HSSW + 0.5mm ID tubing

Question 13

Gauges of wire for passive stops

Answer 13

0.7mm HSSW (flattened)

Question 14

What is the function of passive mesial stops?

Answer 14

Stop canines drifting back after in place

Question 15

List advantages of URA’s (8)

Answer 15

• Tipping of teeth
• Excellent anchorage
• Cheap
• Non destructive (no etch)
• OH easier to maintain
• Less chair side time required
• Less specialised training required
• Can achieve block movements of teeth

Question 16

List disadvantages of URA’s (4)

Answer 16

• Less precise control of tooth movement
• Compliance necessary
• Can only move 1-2 teeth
• Rotations diff to correct

Question 17

Checks when fitting a URA

Answer 17

• Right appliance
• Right patient
• Right design
• No sharp areas
• Check integrity of wirework (cold working/fractures)
• No signs of trauma
• Check posterior retention (check flyovers first then arrowheads - arrowheads equally going into undercuts)
• Check anterior retention
• Activate appliance (1mm/month)
• Demonstrate insertion + removal + get pt to do it
• Review pt every 4-6wks

Question 18

Advice to patient about URA

Answer 18

Mild discomfort
REASSURE:
means appliance working

Big + bulky
REASSURE:
Get used to it after use

Speech affected
REASSURE:
Practice reading will adapt

Salivary response
REASSURE:
Excess common in first 24hrs will pass

PATIENT INSTRUCTION:

1. Wear 24/7 when sleeping + eating
   - Greatest masticatory load when eating
2. Clean w soft brush after every meal
3. Place in case when contact sports
4. Avoid hard/sticky + hot foods

Non compliance will lengthen tx
Emergency details for any issues