Orthodontic Lab Flashcards
What are the benefits of removable retainers
Easier for oral hygiene as can be removed to clean
Capable of being worn part time if required
Responsibility of patient not orthodontist
What are the benefits of fixed retainers
Px doesn’t need to remember to wear it
Useful when result is unstable
What are high risk of relapse cases
Closure of spaced dentition (including median diastema)
Correction of severely rotated teeth
Substantial movement of lower labial segment
Excessive retrooclination/Proclination
Overjet reduced but lips still incompetent
Reduced PDL support cases
What is the other name for conventional removable retainers
hawley retainer
What is the advantages of the hawley retainers
Simple to construct
Reasonably robust
Rigid enough to maintain transverse corrections
Allows more rapid vertical settling than clear plastic retainers due to lack of complete coverage
What are the advantages of clear plastic retainers
Superior aesthetics
Less interference with speech
More economical and quicker to make
Less likely to break
Ease of fabrication
Superior retention in lower arch
Where do fixed retainers usually fail
upper arch due to biting force
What is a transpalatal arch constructed from
0.9mm HSW
What are the uses of the transpalatal arch
anchorage
rotation
limited widening
How does the transpalatal arch work
Teeth are linked together to help prevent/reduce unwanted mesial molar movement
By fixing the intermolar width which aids transverse anchorage, any mesial movement of the molars means that the buccal roots are more likely to come into contact with the cortical plate of bone which resists subsequent mesial tooth movement
What is the use of palatal arch with nance button
anchorage
What is the quadhelix constructed from
0.9mm HSSW
What are the uses of quadhelix
bilateral expansion
asymmetrical expansion
fan style expansion
rotation of molars
expansion in cleft palate
modified to procline incisors
assisting in habit breaking
