Ortho Lab 1- Retainers, advanced removable

Question 1

What are the types of retainers used in orthodontics?

Answer 1

Hawley- conventional removable (less common)

Thermoplastic

Fixed

Question 2

What happens if you forget to wear retainer for a few days?

Answer 2

Teeth can move- if prolonged periods, retainer will no longer fit and could be damaging to dentition

Question 3

How does Invisalign work?

Answer 3

Successive sets of thermoplastic retainers are given to the patient, each week teeth are moved slightly closer to desired position

Question 4

What are the issues with Invisalign?

Answer 4

Does not replace conventional Ortho
-> teeth may not move each time as expected and next appliance does not fit
-> too much pressure to soon can cause root resorption and necrosis of tooth

Expensive

Question 5

What are the features of transpalatal arch wire?

Answer 5

Made of 0.9 HSSW

Commonly attached to FPM with stainless steel bands (attached via soldering)

Question 6

What is the name of the looped part of the transpalatal arch wire?

Answer 6

Omega loop- adjustment can be made here

Question 7

Why should the omega loop not be in contact with the palate?

Answer 7

As the soft tissue can grow over it

Question 8

What are the uses of the transpalatal arch wire?

Answer 8

Anchorage- keeps 6s in desired position

Reciprocation

Rotation of teeth

Limtited widening or contraction

Question 9

What are the features of the palatal arch with nance button?

Answer 9

Made from 0.9 HSSW

Attached to FPM via SS bands (soldered)

Has acrylic button which contacts palate anteriorly

Question 10

What is the use of PAwNB?

Answer 10

Anchorage

Question 11

What are the drawbacks of PAwNB

Answer 11

Difficult to keep clean- irritation of palate under button can occur

If distalising 6s-
-> coil may need to be opened which can cause rotational movement of teeth and tipping of roots (may impinge on other teeth)
-> equal and opposite force can press on button and cause remodelling in anterior region (seen as step in the bone)

Question 12

What are the features of the quad helix>

Answer 12

Variable appearance- can be adapted for different scenarios

Made of 0.9mm HSSW

Attached to FPMs via SS bands (soldered)

Has 4 coils (can be bi/tri)

Question 13

What are the uses of the quad helix?

Answer 13

Bilateral expansion

Asymmetrical expansion

Fan style expansion

Rotation of Molars

Expansion in cleft palate (often have narrow arch)

Modified to procline incisors

Assist in habit breaking

Question 14

How is assymetircal expansion achieved?

Answer 14

True unilateral is difficult due to anchorage BECAUSE:

If you apply force to the coil which moves the tooth you want, an opposing force will still travel through other coils but is mostly absorbed by them (less movement)

-> Resulting in more expansion on one side than the other

Question 15

What is fan style expansion?

Answer 15

More expansion in anteriors than posteriors or VV

Question 16

How can a quad helix be used as a habit breaker in thumb sucking?

Answer 16

Can be fitted passively and be used to disrupt seal between thumb and palate
-> extra wire can be soldered on with added rake (spikes)

Question 17

Why is it important to break the habit of thumb sucking?

Answer 17

It is associated with narrowing of arch

Question 18

What are the steps in repairing a broken fixed retainer?

Answer 18

 Check every bond on a regular bases to check if bond has come away
 Issues with debonding- plaque accumulation, difficulty cleaning, relapse
To repair
 remove composite using diamond or tungsten carbide bur (thin down until wire is exposed- be careful not to damage this)
 Should be able to pick the composite away after thinning it down (get as much off as possible
 Check for caries, integrity of wire work, check that wire is passive against the tooth (it may be distorted, so moving it back would move tooth)
 Add adhesive primer on, and add composite as before