Orthopedics 9% 6Q Flashcards
Point through which the resultant forces must act on an object to produce bodily movement
Center of Resistance
The center of resistance for single root teeth is approximately ___/___ down the root in bone
⅓
The center of resistance for molars is approximately at:
the level of the furcation
Where the tooth tips/rotates around when the line of force does not pass through CR
center of rotation
When the HG line of force is inferior to CR what movement is produced
CW moment
When the HG line of force is superior to CR what movement is produced
CCW moment
The acceptable force for HG is ____g total of ____g per side
800g
400g
In asymmetric HG, the side that is class I will have the ( shorter / longer ) arm and the side that is class II will have the ( shorter / longer ) arm
shorter
longer
In asymmetric HG, the side that is class II will have the longer arm which is also away from the cheek to counteract what side effect? and also has the added benefit of what?
tendency to create cross bite
more distalization
HG with a unilateral FB can create ( buccal / lingual ) crossbite on Class II side and ( buccal / lingual ) crossbite on Class I side
lingual
buccal
what is the effect on A point for patients undergoing high pull HG Tx?
A point remains stationary
With high pull HG Tx, CCW maxillary rotation will be produced if the line of force is _______ or _______ to the center of resistance
above
mesial
With high pull HG Tx, CW maxillary rotation will be produced if the line of force is _______ or _______ to the center of resistance
below
distal
to get distal movement of the molar, the line of force created by high pull HG must go through:
CR of the molar
the line of force produced by HG is influenced by ___________ and ___________ of the outer bow
length
position
T/F: In HPHG, longer outer bow bent up will have the same force as short outer bow bent down
True
You can counteract observed distal tipping due to high pull HG on upper molars with a ___________ and more gingival outer bow
shorter
you can counter the effects of a tip-back bend, or a CW moment, by using high pull headgear with ( shorter / longer) outer bow
shorter
With cervical pull HG, you can prevent molar crown tipping by moving the outer bow _______________
gingivally
With cervical pull HG, you can create molar translation by moving the outer bow _______________
gingivally
With cervical pull HG, by bending the outer bow ______________, you can create distal movement with extrusion of the crowns by moving the roots to a larger arc
down
typical effects if cervical pull HG include: (2)
tipping the palatal plane
mandibular CW rotation
what is the effect of reverse pull HG on SNA?
increase
at what age should reverse pull HG be used?
8-10
what force should be placed on reverse pull HG? in g and lbs
500-1000g
1-2lbs
(250-500g per side)
what is this functional appliance called:
Bionator
A bionator has incisal and occlusal stops control eruption of teeth. Incisal stops can extend to the facial surface to control their position in the ______________ dimension. Occlusal stops can be adjusted to allow _____________________
AP
Mand. posterior eruption
distal positioning of mandible can cause impingement on the ___________ nerve
auricular nerve
what is this functional appliance
MARA
When using a MARA, the bite tends to (open / deepen ) because it allows for extrusion of ( anterior / posterior ) teeth
deepen
anterior
Relapse of OJ and molar relationship seen following Herbst Tx is from:
( anterior / posterior ) movement of (maxillary / mandibular ) molars and incisors
anterior
maxillary
T/F: Functional Appliance increase mandibular length more than fixed appliances
True
What effect do Class II functional appliances have on the lower incisors?
makes them procline
What effect do Class III functional appliances have on the lower incisors?
makes them upright
what is this appliance called?
twin block
According to Prifitt, he effects of the twin block appliance are ___% skeletal and ___% dental. There tends to be a C2E effect.
40%
60%
Class II elastics cause a ( CW / CCW ) rotation of the occlusal plane; C2E (do / do not ) deepen the bite
CW
do NOT
During lip bumper therapy, 50% of the expansion is seen in ___ days
100
___ - ___% of the effect of lip bumper therapy is due to incisor proclination
45-55%
___ - ___% of the effect of lip bumper therapy is due to molar distalization and tipping
35-50%
___ - ___% of the effect of lip bumper therapy is due to an increase in inter canine width
5-10%
in RPE therapy, the effects are greater in the _________ and ________ regions
anterior
inferior
in RPE therapy, it takes ___ - ___ months to re-establish the suture
4-6
in RPE therapy, the limit to expansion is :
the zygomatic arch
in RPE therapy, ( banded / bonded ) helps control the vertical dimension more
bonded
T/F: a TPA can be used to help maintain the AP position or dimension
FALSE
in magnet orthodontic therapy, a decrease in distance of magnets by 50% = ___% increase in force
400
