ortho Flashcards
(179 cards)
1
Q
what can you use to get retention on a removable appliance
A
- adams, delta clasps
- labial bow
2
Q
what elements must be included in the upper removable appliance design
A
- retention
- active components
- anchorage
- base plate modifications
3
Q
what are removable appliances mainly made of
A
acrylic and wire
4
Q
what are removable appliances often used with
A
adjunct to fixed appliance
5
Q
name 4 active components of removable appliances
A
- springs
- biteplanes
- screws
- bows
6
Q
when is a removable appliance passive
A
for retention
7
Q
name 6 types of removable appliances
A
- interceptive appliance
- space maintainer
- pre-surgical orthopaedics
- active plate
- retainer
- functional appliances
8
Q
what why is there less iatrogenic damage with removable appliances
A
pt can remove to brush teeth
9
Q
what is needed from the pt to place removable appliances
A
good compliance
10
Q
what ortho disadvantage is there to removable appliances
A
restricting to tipping movements - very difficult to get bodily movement
11
Q
how many teeth can be moved at one time with removable appliances
A
ideally only a couple at a time
12
Q
what are the four components of removable appliances
A
- active components
- retentive components
- anchorage
- baseplate
13
Q
what is the acronym for remembering the components of removable appliances
A
ARAB
14
Q
what width of wire is used for stainless steel springs in removable appliances`
A
0.5-0.7mm
15
Q
what type of stainless steel is used for springs in removable appliances
A
18/8 austenitic stainless steel
16
Q
what increases with the amount of wire used in a spring
A
greater range of the spring
17
Q
what decreases as the amount and range of the spring increases
A
forces exerted
18
Q
what is the equation for force and deflection in stainless steel springs
A
F = d.r⁴/ l³
19
Q
what does r stand for in the equation for force and deflection in stainless steel springs
A
radius of the wire
20
Q
what does d stand for in equation for force and deflection in stainless steel springs
A
deflection of the wire
21
Q
what is deflection of the wire
A
how far away we are moving from the original shape of the wire
22
Q
what does l stand for in the equation for force and deflection in stainless steel springs
A
length of the spring
23
Q
what does increasing the radius of the wire for stainless steel springs in removable appliances by 2 do?
A
increases the forces applied by 16x
24
Q
what does reducing the length of the stainless steel spring in removable appliances by 2 do
A
reduces force applied by 8 times
25
how is the length of the spring reduced in removable appliances
introducing loops
26
what does a thicker wire in removable appliance springs result in
more force
27
what is the max force that can be applied to one tooth
25-40grams
28
where should the force be applied to in removable appliances to reduce the tipping of the tooth
as close as possible to the gingival margin
29
name 4 springs of removable appliances
- z springs
- t springs
- buccal canine retractors
- palatal finger springs
30
what active components can be embedded into the baseplate of removable appliances
screws
31
how are screws in removable appliances activated
by turning a key
32
what can expansion or distalisation help with in removable appliances
correct cross bites and create space
33
what does one quarter turn of a key in screw of removable appliances equate to
0.25mm of separation
34
how often would a pt usually turn the key for a removable appliance screw
once per week
35
why might the pt not tolerate screws in removable appliances
quite bulky
36
what can also be done to teeth being moved by removable appliances
clasped for retention
37
how many ways can removable appliances expand
2-3
38
what can a pt use to turn the screw in their removable appliance if they lose their key
paper clip
39
why might you not activate a screw in removable appliances until the second visit
to get the pt used to wearing it first
40
what is retention of removable appliances mainly achieved from
clasping of molar/ premolars
41
why are cribs less effective on primary teeth
less undercuts to engage
42
what clasps are used for retention in incisors in removable appliances
south end/ C clasp
43
name 4 types of claps used in removable appliances
- ball hook
- c clasp/ southend
- adams
- delta
44
what are ball hook clasps good for in removable appliances
keeping twinblocks on
45
how thick would an adam/delta SS clasp around a molar be
0.7mm
46
how thick would an adam/delta SS clasp around a premolar be
0.6mm
47
how thick are southend clasps
0.6-0.7mm
48
how thick are ball hooks on removable appliances
0.7mm
49
how do adams clasps work
engage undercuts at mesal and distal aspects
50
how much undercut can adams cribs engage in
1mm
51
what can be soldered onto an adams clasp
- double cribs
- head gear attachment
52
how are adams clasps adjusted
adams pliers
53
what ideology is used when considering anchorage for removable appliances
for every action there is an equal and opposite reaction
54
name 5 ways to increase anchorage of removable appliances
1. clasp more teeth
2. only move 1-2 teeth at a time
3. lighter forces
4. occlusal capping
5. headgear
55
what should you bear in mind if using occlusal capping in removable appliances
if teeth are covered then are difficult to move
56
what should you consider before giving a pt headgear with removable appliances
theoretical risks
57
what does the baseplate of the removable appliance do
connects the components of the appliance
58
what is the the baseplate made from in removable appliances
acrylic
59
how does the baseplate support anchorage in removable appliances
palatal coverage
60
what does a flat anterior bite plane on baseplate allow for
over-eruption posteriorly
61
what does buccal capping do
over-eruption anteriorly
62
what should you tell the lab when prescribing for removable appliances
- what you are trying to do
- retention components
- active components
- baseplate modifications
- pt details
- draw design
- when its required
63
what is the first thing you should do when fitting a removable appliance
check its for the right pt
64
what should you check the labwork for before fitting a removable appliance
any sharp acrylic
65
where does sharp acrylic tend to be in removable appliances
rugae area
66
what might you need to do when fitting a removable appliance
acrylic burs to trim to get it to fit
67
what do you need to decide at the fit appt of removable appliances
whether to activate the clasps and springs at that appt or the next one
68
what should you get the pt to do once fitted the removable appliance
speak to make sure its not dislodging
69
what should you make sure the pt is able to do before leaving with a removable appliance
take it in and out
70
what time frame should you review the pt after fitting a removable appliance
8 weeks
71
why is there a longer time after fitting a removable appliance for the first time than normal review appts
takes longer to act from the fit appt
72
when should you ask the pt to take their removable appliance out
when cleaning and playing sports
73
what should you warn the pt not to do when cleaning their removable appliance
use boiling water - will change shape
74
what will a pt lisping at the review appt of a removable appliance make you think
theyve not been wearing it
75
what should you check the removable appliance for at review appt
wear, tooth imps on bite planes
76
what should you check the mouth for at review appt of removable appliance
- redness of palate
- indentation of appliance on palate
- trauma from springs
77
what should you check aside from the removable appliance at review appt
teeth that are being moved and anchor teeth
78
what will happen if the pt has had XLA and not been wearing removable appliance
anchorage will be lost - wont fit very well
79
how might you know that teeth are moving from pt wearing removable appliance
teeth may be slightly mobile
80
what may be stopping teeth from moving in removable appliance
- acrylic in the way
- insufficient activation of springs
- unerupted teeth
- retained roots
81
how much should you reactivate springs by in removable appliance at review appt
1-2mm
82
how much tooth movement should happen each month with removable appliance
1mm
83
how is tooth movement achieved in aligners
deformation of aligner
84
how many hours a day does a pt need to wear aligners
22 hrs
85
when would fixed ortho be used for primary teeth
interceptive Tx
86
what control do you have with fixed ortho
3D movement
87
what are fixed ortho in comparison to removable appliances
more anchorage demanding
88
what is tipping in fixed ortho
root stays in place but crown placement is altered
89
what is torque in fixed ortho
whole tooth movement
90
which type of movement has the greatest need for anchorage
torque
91
name 5 indications for fixed ortho
- multiple tooth movements needed
- rotations
- bodily movements
- space closure
- lower arch Tx
92
what does fixed ortho do to a pt in terms of oral health impact
high caries risk
93
name 6 risks of fixed ortho
- decalcification
- root resorption
- loss of periodontal support
- TMJ dysfunction
- fail Tx and relapse
- reversible risks
94
who is in a higher risk bracket for root resorption in fixed ortho
trauma pts
95
what should you do for trauma pts undergoing fixed ortho
take Pa every 6 months
96
what should you do if a pt with fixed ortho has trauma mid-Tx
pause Tx for a while
97
what pt is at risk of loss of periodontal support with fixed ortho
thin biotype
98
where does loss of periodontal support tend to happen with fixed ortho
lower incisors
99
what type of movements may cause loss of periodontal support in fixed ortho
lots of expansion
100
what opinion should you get before going ahead with fixed ortho if there is existing TMJ issues
OS/ OM
101
what should you bear in mind before giving fixed ortho to a pt with parafunctional habits
clenching and grinding will be very painful during fixed ortho
102
what is there mild evidence to support with regards to TMj dysfunction and fixed ortho
cross bite being improved with fixed ortho will improve TMJ dysfucntion
103
how might fixed ortho Tx fail or relapse
- ankylosis
- poor Tx planning
- poor compliance
104
name 2 types of fixed attachments
bands
brackets
105
where are bands for fixed ortho ususally used
molars/ premolars or teeth with ceramic crowns
106
what might you warn a pt undergoing fixed ortho who has crowns before Tx
damage to crowns
107
when might bands be placed over molars or premolars
if crowned
108
what do you need to do before you place a band for fixed ortho
separator first to free up contact points
109
what are bands placed with in fixed ortho
GIC
110
what extra benefit migth fixed ortho bands have
GIC fluoride release
111
where do bands go usually if there is orthognathic surgery
last molar
112
what is fixed ortho made up of
brackets, wire, modules
113
what type of bands will be placed for rotated teeth
figure of 8
114
how do figure of 8 bands work
create alot of friction between module, wire and bracket
115
why dont we use figure of 8 bands for closing gaps in fixed ortho
too much friction so teeth are held too tight and wont move
116
what is a long ligature in fixed ortho
tied together to keep the teeth closed
117
what can ceramic brackets on the palatal/lingual aspect of the tooth cause - particularly on lower incisors
wear
118
when would a gold chain be used
impacted teeth eg canine to guide teeth in
119
what are buttons and power chain good for
de-rotating teeth
120
what are self-ligating brackets
have a clip on them so modules arent needed
121
what are self ligating brackets good for
expanding the arch
122
why are self ligating brackets good for expanding the arch
lighter forces, as less friction between modules and bracket/wire
123
what stops the wire sliding out of place in self ligating brackets
little stops between the brackets
124
when might you not use self ligating brackets
if pt prone to calculus - if builds up over the clips then may struggle to get them off
125
what are the white wires used with ceramic brackets made of
metal - coated in ceramic
126
what do ceramic brackets take longer to do
close gaps
127
why do ceramic brackets take longer to close gaps
more friction
128
what must you consider as a dentist when placing lingual brackets
back
129
why is there less wire bending with lingual brackets
custom made to teeth
130
why ortho advantage might lingual brackets have
prop pt open if deep over bite
131
what fixed ortho system do DDH use
NBT system
132
what size of round wire can be used with NBT system
014, 016, 018
133
when do the teeth start to move more in fixed ortho
whe rectangular wire is placed as fully fills the slot
134
what size slot is there for NBT system
022
135
what does every single bracket have for fixed ortho
prescription built into it
136
what does the prescription built into the bracket decide for fixed ortho
what tip and torque we want
137
what does the prescription built into bracket save us
time putting bends into wire
138
which brackets have a prescription built into them
straightwire
139
what do standard archwire brackets require
arch wire bends to produce ideal tip
140
what are the in and out movements of teeth usually caused by in fixed ortho
the base of the bracket
141
why might the base of the bracket have an angle built into it
to keep the wire straight
142
without offset bends, what do standard edgewise brackets not do
align contact points labio-lingually
143
what is it about straightwire brackets that aligns contact points labio-lingually
variation in thickness of bracket bases
144
what provides the torque control for straightwire brackets
bracket slot cut at an angle to base
145
what are the 3 phases of fixed ortho Tx
- levelling and aligning
- major tooth movement
- finishing
146
what is used for the levelling and aligning stage of fixed ortho
round wire and flexible wire NiTi
147
what does the major tooth movement stage of fixed ortho Tx and what does it correct
SS wire to correct overjet/bite and centreline correction
148
what is done in finishing stage of fixed ortho Tx
detailed alignment
149
what does the wire do as the teeth align more
becomes more passive
150
what wires are used in the alignment phase of fixed ortho for initial straightening
014 wire
151
which wire does the hard work in fixed ortho
thinner wire
152
what does the thicker wire NOT having to do much moving mean in fixed ortho
forces dont increase
153
what happens as the wires straighten up and pull teeth into alignment
deformation energy dissipates
154
what does each new wire have more and less of in fixed ortho
- more deformation energy
- less deformation
155
how do you permanently bend NiTi wire
heat it up
156
what properties do NiTi wires have
- high flexibility
- low force over long range
- shape memory
157
which wire is used to do major tooth movements
rigid wires - 1925 SS wire
158
what do rigid SS wires do to the bracket
fill it as much as possible
159
what happens to the wire at each visit when its rigid SS wire
left unchanged
160
what cause sliding of teeth
powerchain
161
what is powerchain used for
close any gaps in teeth
162
what are coil springs used for in fixed ortho
retraction of teeth
163
what are coil springs made out of
NiTi
164
what are coil springs attached to
button in alveolar bone
165
why is only the gingivae numb when placing buttons in alveolar bone
so we know if we've hit the PDL of a tooth
166
what method replaced alot of headgear
coil springs
167
what do you need from the pt to use elastic bands
compliance
168
how can elastic bands be used in fixed ortho
change things anterioposteriorly
169
what alloy makes up SS wires
iron, chromium and nickel
170
what properties do SS wires have
stiff, resist deformation, no memory
171
how can you tell SS and NiTi apart
SS alot more shiny
172
what kind of wires are used in the finishing stage of fixed ortho
lighter wires
173
why are lighter wires used in the finishing stage of fixed ortho
allows settling of occlusion
174
what is done at finishing stage of fixed ortho
detailing of alignment and interdigitation
175
what might the orthodontist do during the finishing stage of fixed ortho
- fine adjustments to brackets
- bends to arch wire
- elastics
176
what instructions are given to pts with fixed ortho
- told how sore teeth will be
- cleaning instructions
- retainer instructions
177
what would you do as a GDP for a broken bracket
remove and make safe
178
what would you do as a GDP for a lost module
replace if available
179
what would you do as a GDP for a protruding archwire
- brace wax
- cut short with a distal end cutter
