Orthodontics- upper removable appliances Flashcards
How does an upper removable appliance work?
It applies pressure to move the teeth through tipping and tilting movements.
Discuss the advantages and disadvantages of an upper removable appliance.
Adv-
Excellent anchorage
easier to maintain oral hygiene
Non-destructive to tooth surfaces.
Disadv-
Patient can remove it
Can only move 2 teeth at once
Rotations are difficult to correct.
Less precise control of movement.
What are the components of stainless steel?
72% Iron
18% Chronium
8% nickel
- 7% Titanium
- 3 % carbon
What does ARAB stand for ?
Active component
Retentive components.
Achorage
Baseplate/
What is the active component?
The part that is moving the teeth through the application of force.
what type of stainless steel wire is used in orthodontic appliances?
Hard circular stainless steel wire.
Name this active component.
Give :
its function.
Its location
the characteristics of the wire.
Finger Spring and guard.
Moves teeth backwards.
Palatally.
0.5mm HSSW.
Name this active component
Give :
its function.
Its location
the characteristics of the wire.
Z spring.
Pushes teeth straight forward
Palatally.
0.5mm HSSW
Name this active component
Give its position
Characteristics of the wire.
Flapper spring.
Palatally
0.5 HSSW
Name this active component
Give :
Its position
The characteristics of the wire.
T spring.
Buccal movement of the teeth.
Palatally.
0.5mm HSSW
Name this active component.
Give :
its function.
Its location
the characteristics of the wire.
Buccal canine retractor
Retract teeth backwards and inwards.
Buccal.
0.5mm HSSW and 0.5mm internal diameterTubing
Name this active component
Give :
its function.
Its location
the characteristics of the wire.
Robert’s retractor
It moves teeth backwards and provides retention.
Buccal
0.5mm HSSW with 0.5mm of internal tubing.
Why do we use tubing?
To give strengtht to the buccally placed active components as the wire is commonly distorted on the buccal side.
Name the 5 intra-oral displacement forces.
Tongue
Gravity
Chewing through mastication
Talking
Active component.
Name this retentive factor.
What is its function.
Discuss the wire characteristic.
Adam’s clasp
Provides posterior retention. (goes into the undercut of the 6s)
0.7mm HSSW.
Name this retentive factor.
What is its function.
Discuss the wire characteristic.
This is the southend clasp.
Provides anterior retention
0.7mm HSSW
Name this retentive factor.
This is the labial bow.
Which posterior teeth do we choose to clasp and why?
6s and the 4s.
6s- they have the biggest roots .
4s-to prevent wire overlapping (which would happen if we chose the 5s and the 6s)
What is anchorage?
This is to ensure that only the teeth that we want to move, move.
What is the function of the baseplate?
- Join the components together
- Helps with achorage
- Helps for retention/adhesion and cohesion.
What material do we make baseplates in and why?
Self cure acrylic as it is finished in 20minutes
Discuss passive components?
This is the stop, which prevents the tooth moving back into their old position (closing the new gap)
It is made of 0.7mm flattened HSSW.
They are positioned on the side of the tooth in the gap.
How do we deal with anterior crowding?
We extract teeth to make space, and move teeth into the space.
How do we treat an overbite?
We use a flat anteiror bite plane to prop open the lower teeth. This causes a posterior open bite resulting in the continued eruption of the posterior teeth.
When the bite plane is removed, the anterior teeth are proped open. This leaves space anteriorly to move the lower teeth back and then the upper.
What is the length of the flat anterior bite plane and why?
Overjet +3mm.
To allow safe movement of the teeth while biting.
How do we correct an anterior crossbite?
Use a posterior biteplane.
This props open the anterior teeth allowing you to push the upper tooth forward.
The teeth can drop down into the correct position when the biteplane is removed.
Why do the posterior teeth need to be against the posterior biteplate?
If they are not, the teeth will continue to erupt causing an anterior open bite when the posterior biteplane is removed.
How do we reduce both the overjet and overbite?
We push the anterior teeth backwards using a robert’s retractor to reduce the OJ.
But we also use a flat anterior bite plane to facilitate the continued eruption of the posterior teeth. This is trimmed at an angle each month to allow the full length of the tooth to tilt back.
How do we get away with using a robert’s retractor to reduce the OJ?
While it is moving 4 teeth, which is more than advised. The anterior teeth have the smallest roots so we get away with it.
How do we rotate teeth using a removable appliance?
We use a Z spring.
By tightening one side more than the other we can push the tooth forward and at a slight angle
How do you expand the upper arch?
We cut the baseplate in half & it is held together by a midline screw that the patient has to activate once or twice a week.
How much tooth movement occurs a week?
0.2-0.25mm of movement.
What is reciprocal anchorage?
The idea that, each side provides resistance for the other.
How would we just expand one quadrant?
Change where we cut on the baseplate.
List the checks for fitting the appliance.
- Is it the right appliance for the patient?
- Is it what you asked for?
- Are there any areas that could cause trauma?
- Any damage
- Any work hardening?
- Try it in (any signs of blanching)
- Check posterior retention
- Check anterior retention.
- Have you shown the patient the correct way to insert and remove the appliance?
What advice should you give to the patient regarding their removable appliance?
- It’s going to feel bulky but you will get used to it
- You will feel a mild discomfort or pressure- this shows that the appliance is working.
- Initially you will have a lisp, so practice talking in it so that your tongue can adapt (the appliance is impinging on tongue space)
- There will be more saliva (this will reduce after 24 hours)
What instructions should be given regarding the removable appliance?
- Wear it at all times
- Do not wear it during high intensity sport, rugby or hockey.
- Wear it when eating (time when teeth are at greatest risk of moving back to their intial space)
- Avoid hard and sticky foods.
- Be careful with hot food and drinks
- Remove and clean the appliance after every meal.
- Give the patient your details to contact in an emergency.
Label this diagram of the adam’s clasp
What is the function of the bridge?
The bridge keeps the cheeks from the component and gives the patients something to grip on when removing the appliance.
What is the function of the arrowhead?
Engage into the undercut for resistance to displacement forces
What is the function of the tag?
To encorporate mechanical retention.
What happens if the flyover is too high?
- The occlusion is propped open.
- Metal fatigue everytime you bite. There is space for the flyover to move and bend, eventually causing fracture.
- Gumstripper- biting down on the flyover could force the arrowhead into the gingiva ripping it.
What part of the adam’s clasp do you adjust first ?
The flyover.
Label the parts of the finger spring.
What is the function of the finger spring’s coil?
This is where the force is exerted from by uncoiling the tooth.
What do you need to do every month to the finger spring?
Adjust the coil.
Tighten the active arm (when the tooth moves, the arm gets looser- if we don’t tighten it, the arm will inadvertently be pushed buccally)
