ortho lab - session 1 Flashcards
what is a TPA constructed in?
0.9mm HSSW
how is a TPA normally attached to FPMs?
using ortho SS bands
attach appliance using spot welding/soldering
why doesn’t a TPA touch the palate?
because the palate would grow over it
uses of a TPA
anchorage - fixates 6s together so they can’t move independently - significantly increases tooth area - need more force to move all of this
rotation
limited widening or contraction
what is a palatal arch with a nance button constructed in?
0.9mm HSSW
construction and adjustment of a palatal arch with a nance button
constructed in a rigid fixed manner and requires minimal adjustment prior to fitting
adjustment ear loops, acrylic button
how is a palatal arch with a nance button attached to FPMs?
use ortho SS bands, attach appliance using spot welding/soldering
uses of a palatal arch with a nance button
anchorage - prevents 6s moving anteriorly
problems with a palatal arch with a nance button
hygiene - can’t remove acrylic (plaque trap, ulcers, candida etc)
some pts unable to tolerate
not good for moving 6s distally
- open ear loops to apply distal force, but then moves band, causes tipping of tooth, roots moved mesially - not an ideal appliance to do this with
quad helix versatility
versatile - can adapt
what is a quad helix constructed in?
0.9mm (1mm) HSSW
construction and adjustment of a quadhelix
constructed in a rigid fixed manner and requires minimal adjustment prior to fitting
how is a quad helix attached to FPMs?
using ortho SS bands, attach appliance to it using spot welding/soldering
uses of a quadhelix
anchorage
bilateral expansion
asymmetrical expansion (moving both sides but to different degrees)
fan style expansion
rotation of molars
expansion in CLP
modified to procline incisors - extend wires, anterior helices
assist in habit breaking - disrupt seal between thumb and roof of mouth
unilateral contraction
on completion of tx the appliance can be made passive and recemented to use as a retainer
quadhelix asymmetric expansion
moving both sides but to different degrees
difficult to achieve because of newtons 3rd law
adjust coil so close to teeth
cut end of wire - moving less teeth with same force
by the time force gets to the other coil the force will have been dissipated by the coils a bit