Labial Bow Flashcards
what is a labial bow
largely horizontal wire labial to incisor teeth
4 actions of a labial bow
- retention: holding up appliance anteriorly
- guiding: of canines during retraction
- active: retract the incisors
- retention/ retaining: holding teeth in new position
what elements of a removable appliance does the labial bow fulfill?
active component
retentive component
(no anchorage or baseplate)
difference between high labial bow and reverse looped bow
- high labial bow: only suited to use as active component
- reverse looped bow: more versatile. loop comes behind where we work
define retention
capacity of an appliance to remain fixed in the mouth
what is the ideal position of the labial bow in relation to the tooth
bottom incisal 1/3 of tooth
how to activate the labial bow
squeeze at the loop
alternative anterior retainers to the labial bow. compare
Southend clasp: rigid wire, engages undercut. commonly used
Adams anterior clasp: less useful
how does a tooth move in response to contact from spring, potential problems of this
at right angles to point of contact of spring.
if line of force does not pass through centre of resistance –> rotation
what thickness of wire should we use for
a. retention of appliance anteriorly
b. guiding a canine
c. retracting incisors
d. retaining tooth position
a. retention of appliance anteriorly: stiff (thick) wire
b. guiding a canine: stiff (thick) wire
c. retracting incisors: flexible wire
d. retaining tooth position: thick (stiff) wire
when may the labial bow be split in to 2 and why
during incisor retraction, to make wire more flexible
width of wire used for labial bow
0.8mm
common faults with labial bow construction
- kinky (at front)
- flyover not high enough –> interferes with canine retraction
