URA design Flashcards
What does I.O.T.N mean?
- Index of orthodontic treatment need
What is the I.O.T.N?
- Rank malocclusion in terms of significance of various occlusal traits for individuals health and perceived aesthetic impairment
- Identify who would benefit most from ortho treatment
What are the two components of I.O.T.N?
- Aesthetic component (AC)
- Dental health component (DHC)
What are the different types of orthodontics available?
- Fixed ortho
- Conventional removable retainers
- Thermoplastic retainers
- Bonded retainers
What is the aim for URA design?
- Description of what the appliance design is aiming to achieve
What is the anagram of URA design?
A - Active component
R- Retentive
A - Anchorage
B - Base plate
What is the definition of Active component?
- The name of the component or components that will be moving teeth with the application of force
What is the definition of Retentive?
- The resistance to displacement forces
What is the definition of Anchorage?
- The resistance to unwanted tooth movement
What is the definition of Baseplate?
- Connects all the components together as a unit, provides anchorage & assists with retention
How do teeth move?
- Orthodontics based on principle if prolonged force applied to tooth, tooth movement will occur
- Force exerted created pressure
- Causes bone around tooth to remodel
- Remodelling controlled by PDL
- Via osteoclasts and osteoblasts
What is the constituents of stainless steel?
72% - Iron
18% - Chromium
8% - Nickel
1.7% - Titanium
0.3% - Carbon
What are the advantages of removable orthodontics?
- Tipping of teeth
- Excellent Anchorage
- Generally cheaper than fixed
- Shorter chairside time required
- Oral hygiene is easier to maintain
- Non- destructive to tooth surface
- Less specialised training required to manage
- Can be easily adapted for overbite reduction
- Can achieve block movements
What are the disadvantages of removable orthodontics?
- Less precise control of tooth movement
- Can be easily removed by the patient
- Generally only 1-2 teeth can be moved at one time
- Specialist technical staff required to construct the appliances
- Rotations very difficult to correct
When fitting a URA what are the steps you follow?
- Right appliance, right patient
- Check it matches design
- Inspect and run finger over all surfaces for sharp or potentially traumatic areas
- Check integrity of wirework
- Insert into mouth and check for blanching or soft tissue trauma
- Check posterior retention (are clasps engaging undercuts)
- Check anterior retention
- Activate appliance (1mm movement per month)
- Demonstrate correct insertion and removal and ensure patient does this
- Book review appointment for 4-6 weeks
What is the patient info and instructions after URA?
- Appliance will feel big and bulky (this is normal and they will get used to it)
- May cause initial excessive salivation (pass within 24hrs)
- May impinge speech for short period of time (practise reading a book aloud at home and it will subside)
- May cause initial discomfort or ache (normal and indicates appliance is working)
- To be worn 24/7 inc meal and sleep
- Remove after every meal and clean with soft brush
- Remove and store in protective container during active or contact sports
- Avoid hard or stick foods that may damage appliance
- Be cautious with hot or drinks
- Missing appointments and non-compliance will significantly lengthen treatment time
- Provide emergency contact details in case any problem arise
What are the design appliances for Retract canines, 1st Premolars extracted, 6mm Overjet (OJ) + Reduce Overbite (OB)
Aim = Construct URA to retract 13+23 + reduce overbite
A = 13 + 23, Palatal finger springs + guards, 0.5mm HSSW
R = 16 + 26, Adams clasps, 0.7mm HSSW
11 + 21, Southend clasp, 0.7mm HSSW
A = Moving only 2 teeth
B = Self cure PMMA
Flat anterior Bite plane (FABP), OJ +3mm
Why do we add 3mm to whatever the overjet is when doing a FABP?
- If did not add 3 mm
- Lower anterior would retrocline
- Overjet would not be reduced
After we have reduced the overbite what can we do next?
- Make a whole new URA to tip the front teeth back to reduce the overjet
What are some retentive components and their gauges of wire?
Adams clasp = 0.7mm HSSW
Southend clasp = 0.7mm HSSW
Labial bows = 0.7mm HSSW
What are some palatally placed active components?
Finger springs + guard = 0.5mm HSSW
Z-spring = 0.5mm HSSW
Flapper spring = 0.5mm HSSW
T-spring = 0.5mm HSSW
What are some buccally placed active components and their gauges of wire?
Buccal canine retractor = 0.5mm HSSW (sheathed with 0.5mm internal diameter tubing)
Roberts retractor = 0.5mm HSSW (sheathed with 0.5mm internal diameter tubing)
What is the passive component and it’s gauge of wire in URA design?
Stops = 0.7mm hard stainless steel (flattened)
What would the appliance design be for Buccally placed canines, 1st Premolars extracted, 6mm (OJ) + Reduce (OB)
Aim = Pls construct URA to retract buccally placed canines and reduce OB
A = 13+23, buccal canine retractors 0.5mm HSSW + 0.5mm I.D tubing
R = 16 + 26 Adams clasp 0.7mm HSSW
11 + 21 Southend clasp 0.7mm HSSW
A = Moving only 2 teeth
B = Self cure PMMA
FABP, OJ + 3mm
What is the appliance design for URA to correct 12 anterior crossbite?
Aim - Pls construct URA to correct 12 anterior crossbite
A = 12 Z-finger spring 0.5mm HSSW
R = 16 + 26 Adams clasp 0.7mm HSSW
14 + 24 Adams clasp 0.7mm HSSW
A = Moving only 1 tooth
B = Self cure PMMA
Posterior bite plane (PBP)
Why do use a posterior bite plane when correcting anterior crossbite?
- To ensure posterior teeth don’t continue to erupt
- If they did this would cause overbite
What are some different uses of casts in orthodontics?
- Motivation for patient
- Design appliances
- Form of record
- Teaching
- Able to see changes in occlusion
- Pt explanation
