fixed appliances Flashcards
What is an fixed appliance and what does it consist of
An appliance which is fixed to the teeth and cannot be
removed by the patient that consists of; brackets, archwires and auxillaries
What are the differences between fixed and removable appliances
Fixed gives complex tooth movements and 3D control of teeth whereas URA only provide simple tooth movements such as tipping
Fixed aplliances allow the control of root movement whereas URA give none
Fixed appliances are less dependant on Pt compliance compared to URA
Fixed has a risk of iatrogenic damage whereas URA have less of a risk
Fixed appliances give poor intrinsic anchorage whereas URA gives good intrinsic anchorage
When would you use fixed appliances
Correction of mild to moderate skeletal discrepancies
Alignment of teeth
Correction of rotations
Correction of centrelines
Overbite/jet reduction
Closure/creation of spaces
Vertical movement of teeth
What is the main Tx goal of ortho
To achieve andrews six keys
What are Andrews 6 keys
Tight approximal contacts with no rotations
Class 1 incisors
Class 1 Molars
Flat occlusal plane or slight curve of spee
Long axis of tooth slight mesial inclination, exceot from the lower incisors
The crowns of the canines back to the molards have a lingual inclination
what are the components of a fixed appliance
Bracket/ Tube
Band
Archwire
Modules
Auxillaries
Anchorage components
Force generating components
What are the components of a bracket
Bracket slot
Tie wings
Bracket base
What materials are normally used for brackets
Metal- SS, CoCr, Ti, Au
Polymers
Ceramics
How are brackets/tubes bonded to teeth
Composite via acid etch technique
How are molar bands bonded to teeth
GI
What materials commonly used for arch wires
SS
NiTi
CoCr
What are the properties of a NiTi arch wire that makes it good
Flexible
Light continous force
Shape memory
-returns to its og shape and cannot bend
Higher friction than SS
What are the properties of a SS archwire that makes it good
Low friction to slide teeth
Formable
-bends and loops
What are the force generating components in fixed appliances
Elasatic power chain
NiTi coils
Intra-oral elastics
Active ligatures
What different forms of anchorage are there im fixed appliances
Simple
Compound
Reciprocal
What is simple anchorage
Pits one tooth against another as they move together
the resistance of the anchorage unit to tipping is utilized to move another tooth with the anchorage tooth combined root surface area two times that of the teeth to be moved
What is compound anchorage
the type of anchorage where more than one tooth with greater anchorage potential are used to move a tooth/group of teeth with lesser support
What is reciprocal anchorage
the resistance offered by two malposed units, when the dissipation of equal and opposite forces tends to move each unit towards a more normal occlusion
How is absolute anchorage achieved
Temporary anchorage devices (TADS)
-Non osseointegrating mini screw
What do cortical plates provide
increased resistance to tooth movement and maintains intermolar width
What features have a high relapse potential
Diastema/ space closure
Rotations
Palatally ectopic canines
Proclination of lower incisors
Anterior open bite
Instanding upper lateral incisors
When would a fixed ortho retainer be used
Space closure
Diastema
Proclination of lower labial segment
Perio cases
Ectopic canines
Instanding upper 2’s
What are the main risks of fixed appliances
Decalcification
root resorption
Relapse
What is true is true in relation to torque and fixed appliances
Torque is the angulation of the tooth in a bucco-lingual direction
