Removable and fixed expanders/ retainers

Question 1

Identify the types of fixed palatal expanders used for the primary dentition (2) and permanent dentition (1)

Answer 1

Early mixed dentition:
• W- arch
• Quad helix

Late mixed dentition/ permanent:
• Bonded rapid maxillary expander

Question 2

Describe bonded rapid maxillary expander in terms of

• How it is used
• How long it should be worn
• Its 3 components (where it is placed)

Answer 2

How it is used:
• Turn 0.2- 0.5 mm a day
• Need to over- expand to account for relapse

How long it is used:
• The expander must be retained for 6 months to minimise relapse

Components:
• Jackscrew
• Bands around molars/ premolars
• A rest on premolar

Question 3

Briefly describe removable expanders in terms of:

• Purpose
• What the active component is
• Who it is most effective for

Answer 3

Removable expanders:
Purpose:
• Corrects an overbite and creates space in causes of maxillary crowding

Active component:
• The active element is a jackscrew
• Its function is to separate sections of the palate
• The screw is open with a key, with 0.2 - 0.5mm of expansion per week

Who it is most effective for:
• Very effective in the early mixed dentition